Csharp/C Sharp by API/System.Windows.Forms/CheckedListBox

CheckedListBox.CheckOnClick

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.CheckState.Checked

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.CheckState.Indeterminate

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.GetItemCheckState

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.GetItemText

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.ItemCheck

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.Items

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.Items.Add

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.Items.AddRang

<source lang="csharp"> using System; using System.Collections.Generic; using System.ruponentModel; using System.Data; using System.Drawing; using System.Windows.Forms;

class Form1 : Form {

   public Form1() {
       InitializeComponent();
       this.checkedListBoxPossibleValue.Items.Add("Ten");
   }
   private void buttonMove_Click(object sender, EventArgs e) {
       if (this.checkedListBoxPossibleValue.CheckedItems.Count > 0) {
           this.listBoxSelected.Items.Clear();
           foreach (string item in this.checkedListBoxPossibleValue.CheckedItems) {
               this.listBoxSelected.Items.Add(item.ToString());
           }
           for (int i = 0; i < this.checkedListBoxPossibleValue.Items.Count; i++)
               this.checkedListBoxPossibleValue.SetItemChecked(i, false);
       }
   }
   private void InitializeComponent() {
       this.checkedListBoxPossibleValue = new System.Windows.Forms.CheckedListBox();
       this.buttonMove = new System.Windows.Forms.Button();
       this.listBoxSelected = new System.Windows.Forms.ListBox();
       this.SuspendLayout();
       this.checkedListBoxPossibleValue.CheckOnClick = true;
       this.checkedListBoxPossibleValue.FormattingEnabled = true;
       this.checkedListBoxPossibleValue.Items.AddRange(new object[] {
           "One",
           "Two",
           "Three",
           "Four",
           "Five",
           "Six",
           "Seven",
           "Eight",
           "Nine"});
       this.checkedListBoxPossibleValue.Location = new System.Drawing.Point(13, 13);
       this.checkedListBoxPossibleValue.Name = "checkedListBoxPossibleValue";
       this.checkedListBoxPossibleValue.Size = new System.Drawing.Size(187, 242);
       this.buttonMove.Location = new System.Drawing.Point(207, 129);
       this.buttonMove.Text = "Move";
       this.buttonMove.Click += new System.EventHandler(this.buttonMove_Click);
       this.listBoxSelected.FormattingEnabled = true;
       this.listBoxSelected.Location = new System.Drawing.Point(288, 13);
       this.listBoxSelected.SelectionMode = System.Windows.Forms.SelectionMode.MultiExtended;
       this.listBoxSelected.Size = new System.Drawing.Size(187, 238);
       this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
       this.ClientSize = new System.Drawing.Size(492, 273);
       this.Controls.Add(this.listBoxSelected);
       this.Controls.Add(this.buttonMove);
       this.Controls.Add(this.checkedListBoxPossibleValue);
       this.Text = "List Boxes";
       this.ResumeLayout(false);
   }
   private System.Windows.Forms.CheckedListBox checkedListBoxPossibleValue;
   private System.Windows.Forms.Button buttonMove;
   private System.Windows.Forms.ListBox listBoxSelected;
   [STAThread]
   static void Main() {
       Application.EnableVisualStyles();
       Application.Run(new Form1());
   }

}

 </source>

CheckedListBox.MultiColumn

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.ScrollAlwaysVisible

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.SelectedIndexChanged

<source lang="csharp"> using System; using System.Windows.Forms; using System.Drawing; using System.ruponentModel;

public class CheckedListBoxDemo:Form{

 CheckedListBox FavLangs;
 GroupBox grpControls;
 Button AddValue;
 Button EditValue;
 Button DeleteValue;
 Button ShowValues;
 TextBox OldValue;
 TextBox NewValue;
 Label OldCaption;
 Label NewCaption;
 CheckBox chkAll;

 public CheckedListBoxDemo(){
   grpControls=new GroupBox();
   grpControls.Text="CheckedListBox Demo";

   AddValue=new Button();
   AddValue.Text="&Add";
   AddValue.Click+=new EventHandler(Add_Click);
   
   EditValue=new Button();
   EditValue.Text="&Edit";
   EditValue.Click+=new EventHandler(Edit_Click);
   
   DeleteValue=new Button();
   DeleteValue.Text="&Delete";
   DeleteValue.Click+=new EventHandler(Delete_Click);
   
   ShowValues=new Button();
   ShowValues.Text="&Show";
   //ShowValues.Click+=new EventHandler(ShowValues_Click);
   ShowValues.Click+=new EventHandler(Checked_Changed);
   
   OldValue=new TextBox();
   OldValue.ReadOnly=true;
   NewValue=new TextBox();

   OldCaption=new Label();
   OldCaption.Text="Old Value:";
   NewCaption=new Label();
   NewCaption.Text="New Value:";
   chkAll=new CheckBox();
   chkAll.Text="Check/UnCheck All";
   chkAll.CheckedChanged+= new EventHandler(Checked_Changed);
   chkAll.Width=175;

   OldCaption.Location=new Point(15,15);
   PositionControl(OldCaption,OldValue,true);
   PositionControl(OldCaption,NewCaption,false);
   PositionControl(OldValue,NewValue,false);
   PositionControl(NewCaption,AddValue,false);
   PositionControl(AddValue,EditValue,true);
   PositionControl(EditValue,DeleteValue,true);
   PositionControl(DeleteValue,ShowValues,true);
   PositionControl(AddValue,chkAll,false);

   grpControls.Controls.AddRange(new Control[]{OldCaption,OldValue,NewCaption,NewValue,AddValue,EditValue,DeleteValue,ShowValues,chkAll});
   grpControls.Size=new Size(450,200);

   FavLangs=new CheckedListBox();
   FavLangs.Location=new Point(10,10);
   FavLangs.SelectedIndexChanged+=new EventHandler(SelectedIndex_Changed);

   grpControls.Location=new Point(FavLangs.Left+FavLangs.Width+20,FavLangs.Top);
   this.Controls.AddRange(new Control[]{FavLangs,grpControls});
 }

 private void PositionControl(Control source,Control destination,bool CanPlaceHorizontal)
 {
   if(CanPlaceHorizontal){
     destination.Location=new Point(source.Left+source.Width+20,source.Top);
   }else{
     destination.Location=new Point(source.Left,source.Top+source.Height+20);      
   }
 }

 private void Add_Click(object sender,EventArgs e){
   ((Button)sender).Text = "aaa";
   
   if(NewValue.Text.Trim()!=""){
     FavLangs.Items.Add(NewValue.Text);
   }else{
     MessageBox.Show("Enter a Value to Add");
   }
 }

 private void SelectedIndex_Changed(object sender,EventArgs e){
   OldValue.Text=FavLangs.Items[FavLangs.SelectedIndex].ToString();
 }

 private void Edit_Click(object sender,EventArgs e){
   if(FavLangs.SelectedIndex==-1){
     MessageBox.Show("Select a Item to Edit");
   } else{
    if(NewValue.Text.Trim()!=""){
       FavLangs.Items[FavLangs.SelectedIndex]=NewValue.Text;
    }
     else
     {
       MessageBox.Show("Enter a Value to Edit");
     }            
   }
 }

 private void Delete_Click(object sender,EventArgs e)
 {
   if(FavLangs.SelectedIndex!=-1)
   {
     FavLangs.Items.RemoveAt(FavLangs.SelectedIndex);
   }
   else
   {
     MessageBox.Show("Select a Item to Delete");
   }
 }

 private void ShowValues_Click(object sender,EventArgs e){
   string SelectedValues="The following value(s) are Selected:\n" + new String("-",48) + "\n";
   for(int i=0;i<FavLangs.CheckedItems.Count;i++){
     SelectedValues+=FavLangs.CheckedItems[i].ToString() + "\n";
   }
   MessageBox.Show(SelectedValues);
 }

 private void Checked_Changed(object sender,EventArgs e){
     for(int i=0;i<FavLangs.Items.Count;i++){
         FavLangs.SetItemChecked(i,chkAll.Checked);
     }    
 }

 public static void Main(){
     Application.Run(new CheckedListBoxDemo());
 }

}

 </source>

CheckedListBox.SetItemCheckState

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>

CheckedListBox.ThreeDCheckBoxes

<source lang="csharp">

using System; using System.Drawing; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class CheckedListBoxes : Form {

 CheckedListBox clb;
 Button btnToggle;
 Button btnClear;
 String str;
 public CheckedListBoxes()
 {
   Size = new Size(300,400);
   this.Load += new EventHandler(this_Load);
   clb = new CheckedListBox();
   clb.Parent = this;
   clb.Location = new Point(10,10);
   clb.Size = new Size(ClientSize.Width - 20, Height - 240);
   clb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
   clb.BorderStyle = BorderStyle.Fixed3D;
   clb.MultiColumn = true;
   clb.ScrollAlwaysVisible = true;
   clb.ThreeDCheckBoxes = true;  
   clb.CheckOnClick = true;
   clb.ItemCheck += new ItemCheckEventHandler(clb_ItemCheck);
   btnToggle = new Button();
   btnToggle.Parent = this;
   btnToggle.Text = "Toggle Indeterminate";
   btnToggle.Size = new Size((int)(Font.Height * .75) * btnToggle.Text.Length, Font.Height + 10);
   btnToggle.Location = new Point( clb.Left, clb.Bottom + 10);
   btnToggle.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnToggle.Click += new System.EventHandler(btnToggle_Click);
   btnClear = new Button();
   btnClear.Parent = this;
   btnClear.Text = "Clear All";
   btnClear.Size = new Size((int)(Font.Height * .75) * btnClear.Text.Length, Font.Height + 10);
   btnClear.Location = new Point(btnToggle.Left, btnToggle.Bottom + 10);
   btnClear.Anchor = AnchorStyles.Left | AnchorStyles.Bottom;
   btnClear.Click += new System.EventHandler(btnClear_Click);
   clb.Items.Add("12345");
     clb.Items.Add("67890");      
     clb.Items.Add("7890");      
     clb.Items.Add("890");            
 }  
 static void Main() 
 {
   Application.Run(new CheckedListBoxes());
 }
 private void btnToggle_Click(object sender, EventArgs e)
 {
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     if (clb.GetItemCheckState(i) == CheckState.Checked)
     {
       clb.SetItemCheckState(i, CheckState.Indeterminate);  
     }
     else if (clb.GetItemCheckState(i) == CheckState.Indeterminate)
     {
       clb.SetItemCheckState(i, CheckState.Checked);  
     }
   }  
 }
 private void btnClear_Click(object sender, EventArgs e)
 {
   clb.ClearSelected();
   for (int i = 0; i <= (clb.Items.Count - 1); i++)
   {
     clb.SetItemChecked(i, false);  
   }
 }
 private void clb_ItemCheck(object sender, ItemCheckEventArgs e)
 {
   Console.WriteLine("Current Item:" + clb.GetItemText(clb.Items[e.Index]));
   Console.WriteLine("Current Index:" + e.Index.ToString() );
   Console.WriteLine("Current Value:" + e.CurrentValue.ToString() );
   Console.WriteLine("New Value:" + e.NewValue.ToString() );
 }
 private void clb_SelectedIndexChanged(object sender, EventArgs e)
 {
   Console.WriteLine("Selected Items:" + clb.SelectedItems.Count.ToString() );
   Console.WriteLine("Checked Items:" + clb.CheckedItems.Count.ToString() );
 }
 private void this_Load(object sender, EventArgs e)
 {
   clb.SelectedIndexChanged += new EventHandler(clb_SelectedIndexChanged);
 }

}

 </source>