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

Материал из .Net Framework эксперт
Перейти к: навигация, поиск

ComboBox.AutoCompleteMode

 

using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
public class Form1 : Form
{
    private System.Windows.Forms.ruboBox lstColors;
  public Form1() {
        InitializeComponent();
        string[] colorNames;
        colorNames = System.Enum.GetNames(typeof(KnownColor));
        lstColors.Items.AddRange(colorNames);
  }
    private void InitializeComponent()
    {
        this.lstColors = new System.Windows.Forms.ruboBox();
        this.SuspendLayout();
        this.lstColors.AutoCompleteMode = ((System.Windows.Forms.AutoCompleteMode)((System.Windows.Forms.AutoCompleteMode.Suggest | System.Windows.Forms.AutoCompleteMode.Append)));
        this.lstColors.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.ListItems;
        this.lstColors.FormattingEnabled = true;
        this.lstColors.Location = new System.Drawing.Point(13, 13);
        this.lstColors.Name = "lstColors";
        this.lstColors.Size = new System.Drawing.Size(267, 21);
        this.lstColors.TabIndex = 0;
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);
        this.ClientSize = new System.Drawing.Size(296, 82);
        this.Controls.Add(this.lstColors);
        this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
        this.Name = "Form1";
        this.Text = "AutoComplete";
        this.ResumeLayout(false);
    }
  [STAThread]
  static void Main()
  {
    Application.EnableVisualStyles();
    Application.Run(new Form1());
  }
}


ComboBox.AutoCompleteSource

 
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
public class Form1 : Form
{
    private System.Windows.Forms.ruboBox lstColors;
  public Form1() {
        InitializeComponent();
        string[] colorNames;
        colorNames = System.Enum.GetNames(typeof(KnownColor));
        lstColors.Items.AddRange(colorNames);
  }
    private void InitializeComponent()
    {
        this.lstColors = new System.Windows.Forms.ruboBox();
        this.SuspendLayout();
        this.lstColors.AutoCompleteMode = ((System.Windows.Forms.AutoCompleteMode)((System.Windows.Forms.AutoCompleteMode.Suggest | System.Windows.Forms.AutoCompleteMode.Append)));
        this.lstColors.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.ListItems;
        this.lstColors.FormattingEnabled = true;
        this.lstColors.Location = new System.Drawing.Point(13, 13);
        this.lstColors.Name = "lstColors";
        this.lstColors.Size = new System.Drawing.Size(267, 21);
        this.lstColors.TabIndex = 0;
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);
        this.ClientSize = new System.Drawing.Size(296, 82);
        this.Controls.Add(this.lstColors);
        this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
        this.Name = "Form1";
        this.Text = "AutoComplete";
        this.ResumeLayout(false);
    }
  [STAThread]
  static void Main()
  {
    Application.EnableVisualStyles();
    Application.Run(new Form1());
  }
}


ComboBox.DrawItem

  

using System;
using System.Drawing;
using System.Collections;
using System.ruponentModel;
using System.Windows.Forms;
using System.Data;
public class Form1 : System.Windows.Forms.Form {
    private System.Windows.Forms.ruboBox comboBox1 = new System.Windows.Forms.ruboBox();
    private System.Windows.Forms.Label label1 = new System.Windows.Forms.Label();
    private System.Windows.Forms.ruboBox comboBox2 = new System.Windows.Forms.ruboBox();
    private System.Windows.Forms.Label label2 = new System.Windows.Forms.Label();
    ArrayList colorArray = new ArrayList();
    ArrayList fontArray = new ArrayList();
    public Form1() {
        this.SuspendLayout();
        this.ruboBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable;
        this.ruboBox1.ItemHeight = 25;
        this.ruboBox1.Location = new System.Drawing.Point(16, 40);
        this.ruboBox1.Size = new System.Drawing.Size(264, 31);
        this.ruboBox1.SelectedIndexChanged += new System.EventHandler(this.MyItemSelected);
        this.ruboBox1.MeasureItem += new System.Windows.Forms.MeasureItemEventHandler(this.ruboBox1_MeasureItem);
        this.ruboBox1.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.ruboBox1_DrawItem);
        this.label1.Location = new System.Drawing.Point(16, 16);
        this.label1.Size = new System.Drawing.Size(100, 16);
        this.label1.Text = "Font Combo Box";
        this.ruboBox2.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;
        this.ruboBox2.DropDownStyle = System.Windows.Forms.ruboBoxStyle.DropDownList;
        this.ruboBox2.ItemHeight = 20;
        this.ruboBox2.Location = new System.Drawing.Point(16, 104);
        this.ruboBox2.Size = new System.Drawing.Size(264, 26);
        this.ruboBox2.SelectedIndexChanged += new System.EventHandler(this.MyItemSelected);
        this.ruboBox2.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.ruboBox2_DrawItem);
        this.label2.Location = new System.Drawing.Point(24, 80);
        this.label2.Text = "Color Combo Box";
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
        this.ClientSize = new System.Drawing.Size(312, 157);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                      this.label2,
                                      this.label1,
                                      this.ruboBox1,
                                      this.ruboBox2});
        this.Load += new System.EventHandler(this.Form1_Load);
        this.ResumeLayout(false);
    }
    [STAThread]
    static void Main() {
        Application.Run(new Form1());
    }
    private void Form1_Load(object sender, System.EventArgs e) {
        colorArray.Add(new SolidBrush(Color.Yellow));
        colorArray.Add(new SolidBrush(Color.Black));
        colorArray.Add(new SolidBrush(Color.Azure));
        colorArray.Add(new SolidBrush(Color.Firebrick));
        colorArray.Add(new SolidBrush(Color.DarkMagenta));
        comboBox2.Items.Add("A");
        comboBox2.Items.Add("B");
        comboBox2.Items.Add("C");
        comboBox2.Items.Add("D");
        comboBox2.Items.Add("E");
        fontArray.Add(new Font("Ariel", 15, FontStyle.Bold));
        fontArray.Add(new Font("Courier", 12, FontStyle.Italic));
        fontArray.Add(new Font("Veranda", 14, FontStyle.Bold));
        fontArray.Add(new Font("System", 10, FontStyle.Strikeout));
        fontArray.Add(new Font("Century SchoolBook", 15, FontStyle.Underline));
        comboBox1.Items.Add("W");
        comboBox1.Items.Add("H");
        comboBox1.Items.Add("P");
        comboBox1.Items.Add("D");
        comboBox1.Items.Add("L");
    }
    private void comboBox1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e) {
        Graphics g = e.Graphics;
        Rectangle r = e.Bounds;
        Font fn = null;
        if (e.Index >= 0) {
            fn = (Font)fontArray[e.Index];
            string s = (string)comboBox1.Items[e.Index];
            StringFormat sf = new StringFormat();
            sf.Alignment = StringAlignment.Near;
            e.Graphics.DrawRectangle(new Pen(new SolidBrush(Color.Black), 2), r);
            if (e.State == (DrawItemState.NoAccelerator | DrawItemState.NoFocusRect)) {
                e.Graphics.FillRectangle(new SolidBrush(Color.White), r);
                e.Graphics.DrawString(s, fn, new SolidBrush(Color.Black), r, sf);
                e.DrawFocusRectangle();
            } else {
                e.Graphics.FillRectangle(new SolidBrush(Color.LightBlue), r);
                e.Graphics.DrawString(s, fn, new SolidBrush(Color.Red), r, sf);
                e.DrawFocusRectangle();
            }
        }
    }
    private void comboBox2_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e) {
        Graphics g = e.Graphics;
        Rectangle r = e.Bounds;
        if (e.Index >= 0) {
            Rectangle rd = r;
            rd.Width = 100;
            Rectangle rt = r;
            SolidBrush b = (SolidBrush)colorArray[e.Index];
            g.FillRectangle(b, rd);
            StringFormat sf = new StringFormat();
            sf.Alignment = StringAlignment.Near;
            Console.WriteLine(e.State.ToString());
            e.Graphics.DrawRectangle(new Pen(new SolidBrush(Color.Black), 2), r);
            if (e.State == (DrawItemState.NoAccelerator | DrawItemState.NoFocusRect)) {
                e.Graphics.FillRectangle(new SolidBrush(Color.White), r);
                e.Graphics.DrawString(b.Color.Name, new Font("Ariel", 8, FontStyle.Bold), new SolidBrush(Color.Black), r, sf);
                e.DrawFocusRectangle();
            } else {
                e.Graphics.FillRectangle(new SolidBrush(Color.LightBlue), r);
                e.Graphics.DrawString(b.Color.Name, new Font("Veranda", 12, FontStyle.Bold), new SolidBrush(Color.Red), r, sf);
                e.DrawFocusRectangle();
            }
        }
    }
    private void MyItemSelected(object sender, System.EventArgs e) {
        ComboBox cb = null;
        if (sender.Equals(comboBox1))
            cb = comboBox1;
        else
            cb = comboBox2;
        int x = cb.SelectedIndex;
        if (sender.Equals(comboBox1)) {
            Console.WriteLine("Item Selected is = " + (string)cb.Items[x]);
        } else {
            SolidBrush br = (SolidBrush)colorArray[x];
            Console.WriteLine("Color Selected is = " + br.Color.Name);
        }
    }
    private void comboBox1_MeasureItem(object sender, System.Windows.Forms.MeasureItemEventArgs e) {
        if (e.Index % 2 == 0) {
            e.ItemHeight = 45;
            e.ItemWidth = 20;
        } else {
            e.ItemHeight = 25;
            e.ItemWidth = 10;
        }
    }
}


ComboBox.FormattingEnabled

 
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
public class Form1 : Form
{
    private System.Windows.Forms.ruboBox lstColors;
  public Form1() {
        InitializeComponent();
        string[] colorNames;
        colorNames = System.Enum.GetNames(typeof(KnownColor));
        lstColors.Items.AddRange(colorNames);
  }
    private void InitializeComponent()
    {
        this.lstColors = new System.Windows.Forms.ruboBox();
        this.SuspendLayout();
        this.lstColors.AutoCompleteMode = ((System.Windows.Forms.AutoCompleteMode)((System.Windows.Forms.AutoCompleteMode.Suggest | System.Windows.Forms.AutoCompleteMode.Append)));
        this.lstColors.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.ListItems;
        this.lstColors.FormattingEnabled = true;
        this.lstColors.Location = new System.Drawing.Point(13, 13);
        this.lstColors.Name = "lstColors";
        this.lstColors.Size = new System.Drawing.Size(267, 21);
        this.lstColors.TabIndex = 0;
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);
        this.ClientSize = new System.Drawing.Size(296, 82);
        this.Controls.Add(this.lstColors);
        this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
        this.Name = "Form1";
        this.Text = "AutoComplete";
        this.ResumeLayout(false);
    }
  [STAThread]
  static void Main()
  {
    Application.EnableVisualStyles();
    Application.Run(new Form1());
  }
}


ComboBox.Items

   
using System;
using System.Drawing;
using System.Windows.Forms;
public class Select : Form {
  private Button draw = new Button();
  private ComboBox color = new ComboBox();
  public Select( ) {
    draw.Text = "Draw";
    color.Text = "Choose a color";
    Size = new Size(500,250);
    int w = 20;
    draw.Location = new Point(20,30);
    color.Location = new Point(w += 10 + color.Width, 30);
    color.Items.Add("Red");
    color.Items.Add("Green");
    color.Items.Add("Blue");
    Controls.Add(draw);
    Controls.Add(color);
    draw.Click += new EventHandler(Draw_Click);
  } 
  protected void Draw_Click(Object sender, EventArgs e) {
    if (color.SelectedItem.ToString() == "Red" )
      Console.WriteLine("It is red.");
    else if (color.SelectedItem.ToString() == "Green")
      Console.WriteLine("It is green.");
    else
      Console.WriteLine("It is blue.");
  }
  static void Main() {
    Application.Run(new Select());
  }
}


ComboBox.Leave

  
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;
public class ComboBoxes : Form
{
  ComboBox cmb;
  Button btnDisplay;
  Button btnInsert;
  Button btnSelect;
  Label lblEdit;
  TextBox txtDisplay;
  Boolean boolChange = false;
  Boolean boolProcessed = false;
  public ComboBoxes()
  {
    Size = new Size(300,400);
    this.Load += new EventHandler(this_Load);
    cmb = new ComboBox();
    cmb.Parent = this;
    cmb.Location = new Point(10,10);
    cmb.Size = new Size(ClientSize.Width / 2, Height - 200);
    cmb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
    cmb.DropDownStyle = ComboBoxStyle.DropDown;    
    cmb.DropDownStyle = ComboBoxStyle.Simple;
    cmb.DropDownWidth = (int)(cmb.Width * 1.5);
    cmb.MaxDropDownItems = 12;
    cmb.MaxLength = 20;
    cmb.SelectionChangeCommitted += new EventHandler(cmb_SelectionChangeCommitted);
    cmb.Leave += new EventHandler(cmb_Leave);
    btnInsert = new Button();
    btnInsert.Parent = this;
    btnInsert.Text = "&Insert Item";
    btnInsert.Size = new Size((int)(Font.Height * .75) * btnInsert.Text.Length, cmb.Height);
    btnInsert.Location = new Point(cmb.Right + 10, cmb.Top);
    btnInsert.Click += new System.EventHandler(btnInsert_Click);
    lblEdit = new Label();
    lblEdit.Parent = this;
    lblEdit.BorderStyle = BorderStyle.Fixed3D;
    lblEdit.Location = new Point(cmb.Left, cmb.Bottom + 10);
    lblEdit.BackColor = Color.LightGray;
    lblEdit.Text = "";
    lblEdit.Size = new Size(cmb.DropDownWidth, Font.Height * 2);
    btnDisplay = new Button();
    btnDisplay.Parent = this;
    btnDisplay.Text = "&Display Items";
    btnDisplay.Size = new Size((int)(Font.Height * .75) * btnDisplay.Text.Length, cmb.Height);
    btnDisplay.Location = new Point(lblEdit.Left, lblEdit.Bottom + 10);
    btnDisplay.Click += new System.EventHandler(btnDisplay_Click);
    txtDisplay = new TextBox();
    txtDisplay.Parent = this;
    txtDisplay.Location = new Point(btnDisplay.Left, btnDisplay.Bottom + 10);
    txtDisplay.Multiline = true;
    txtDisplay.ReadOnly = true;
    txtDisplay.BackColor = Color.LightGray;
    txtDisplay.ScrollBars = ScrollBars.Vertical;
    txtDisplay.Text = "";
    txtDisplay.Size = new Size(cmb.DropDownWidth, 200);
    
    btnSelect = new Button();
    btnSelect.Parent = this;
    btnSelect.Text = "&Select 4";
    btnSelect.Size = new Size((int)(Font.Height * .75) * btnSelect.Text.Length, cmb.Height);
    btnSelect.Location = new Point(btnDisplay.Right + 10, btnDisplay.Top);
    btnSelect.Click += new System.EventHandler(btnSelect_Click);
      cmb.Items.Add("A");
      cmb.Items.Add("B");
      cmb.Items.Add("C");
      cmb.Items.Add("D");
      cmb.Items.Add("E");                        
    cmb.SelectedIndex = 0;   
  }
  static void Main() 
  {
    Application.Run(new ComboBoxes());
  }
  private void this_Load(object sender, EventArgs e)
  {
    cmb.TextChanged += new EventHandler(cmb_TextChanged);
    cmb.SelectedIndexChanged += new EventHandler(cmb_SelectedIndexChanged);
  }
  private void cmb_TextChanged(object sender, EventArgs e)
  {
    if (!boolProcessed)
      lblEdit.Text = cmb.Text;
    boolChange = true;
  }    
  private void cmb_SelectedIndexChanged(object sender, EventArgs e)
  {
    if (boolChange)
    {
      boolChange = false;
      boolProcessed = false;
    }
  }
  private void cmb_SelectionChangeCommitted(object sender, EventArgs e)
  {
    if (boolChange)
      ProcessChange();
  }    
  private void cmb_Leave(object sender, EventArgs e)
  {
    if (boolChange)
    {
      ProcessChange();
      boolChange = false;
    }
  }    
  private void ProcessChange()
  {
    lblEdit.Text = "Edited: " + cmb.Text;
    boolProcessed = true;
  }
  private void btnDisplay_Click(object sender, EventArgs e)
  {
    string str = DateTime.Now.ToString() + "\r\n";
    foreach (object item in cmb.Items)
    {
      str += item.ToString() + "\r\n";
    }
    txtDisplay.Text = str;
  }    
  private void btnSelect_Click(object sender, EventArgs e)
  {
    cmb.Select(1,2);
  }    
  private void btnInsert_Click(object sender, EventArgs e)
  {
    if (cmb.FindStringExact(cmb.Text) != -1)
    {
      MessageBox.Show(""" + cmb.Text + "" already exists in the list.\r\n" + 
          "Will not be added again.",
          "Already Exists!");
    }
    else if (cmb.Text == "")
    {
      MessageBox.Show("There is nothing to add.","Nothing There");
    }
    else
    {
      cmb.Items.Add(cmb.Text);
    }
  }
}


ComboBox.SelectedIndexChanged

   
using System;
using System.Drawing;
using System.Windows.Forms;

public class Test : Form {
 
  private RadioButton square = new RadioButton();
  private RadioButton circle = new RadioButton();
  private ComboBox color = new ComboBox();
 
  private Color c = Color.Red;
 
  public Test( ) {
    Text = "Select Item";
    square.Text = "Square";
    circle.Text = "Circle";
    color.Text = "Choose a color";
 
    Size = new Size(400,250);
 
    int w = 20;
    square.Location = new Point(w, 30);
    circle.Location = new Point(w += 10 + square.Width, 30);
    color.Location = new Point(w += 10 + circle.Width, 30);
 
    color.Items.Add("Red");
    color.Items.Add("Green");
    color.Items.Add("Blue");
 
    Controls.Add(square);
    Controls.Add(circle);
    Controls.Add(color);
 
    square.CheckedChanged += new EventHandler(Checked_Changed); 
    circle.CheckedChanged += new EventHandler(Checked_Changed); 
    color.SelectedIndexChanged += new EventHandler(Selected_Index); 
  }
 
  protected override void OnPaint(PaintEventArgs e){
    Graphics g = e.Graphics;
    Brush brush = new SolidBrush(c);
    if (square.Checked)
      g.FillRectangle(brush,100,100,100,100);
    else
      g.FillEllipse(brush,100,100,100,100);
    base.OnPaint( e );
  }
 
  protected void Selected_Index(Object sender, EventArgs e){
    if (color.SelectedItem.ToString() == "Red" )
      c = Color.Red;
    else if (color.SelectedItem.ToString() == "Green")
      c = Color.Green;
    else
      c = Color.Blue;
    Invalidate();
  }
 
  protected void Checked_Changed(Object sender, EventArgs e) {
    Invalidate();
  }
  static void Main() {
    Application.Run(new Test());
  }
}


ComboBox.SelectedItem

   

using System;
using System.Drawing;
using System.Windows.Forms;
public class Select : Form {
  private Button draw = new Button();
  private ComboBox color = new ComboBox();
  public Select( ) {
    draw.Text = "Draw";
    color.Text = "Choose a color";
    Size = new Size(500,250);
    int w = 20;
    draw.Location = new Point(20,30);
    color.Location = new Point(w += 10 + color.Width, 30);
    color.Items.Add("Red");
    color.Items.Add("Green");
    color.Items.Add("Blue");
    Controls.Add(draw);
    Controls.Add(color);
    draw.Click += new EventHandler(Draw_Click);
  } 
  protected void Draw_Click(Object sender, EventArgs e) {
    if (color.SelectedItem.ToString() == "Red" )
      Console.WriteLine("It is red.");
    else if (color.SelectedItem.ToString() == "Green")
      Console.WriteLine("It is green.");
    else
      Console.WriteLine("It is blue.");
  }
  static void Main() {
    Application.Run(new Select());
  }
}


ComboBox.SelectionChangeCommitted

  
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;
public class ComboBoxes : Form
{
  ComboBox cmb;
  Button btnDisplay;
  Button btnInsert;
  Button btnSelect;
  Label lblEdit;
  TextBox txtDisplay;
  Boolean boolChange = false;
  Boolean boolProcessed = false;
  public ComboBoxes()
  {
    Size = new Size(300,400);
    this.Load += new EventHandler(this_Load);
    cmb = new ComboBox();
    cmb.Parent = this;
    cmb.Location = new Point(10,10);
    cmb.Size = new Size(ClientSize.Width / 2, Height - 200);
    cmb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
    cmb.DropDownStyle = ComboBoxStyle.DropDown;    
    cmb.DropDownStyle = ComboBoxStyle.Simple;
    cmb.DropDownWidth = (int)(cmb.Width * 1.5);
    cmb.MaxDropDownItems = 12;
    cmb.MaxLength = 20;
    cmb.SelectionChangeCommitted += new EventHandler(cmb_SelectionChangeCommitted);
    cmb.Leave += new EventHandler(cmb_Leave);
    btnInsert = new Button();
    btnInsert.Parent = this;
    btnInsert.Text = "&Insert Item";
    btnInsert.Size = new Size((int)(Font.Height * .75) * btnInsert.Text.Length, cmb.Height);
    btnInsert.Location = new Point(cmb.Right + 10, cmb.Top);
    btnInsert.Click += new System.EventHandler(btnInsert_Click);
    lblEdit = new Label();
    lblEdit.Parent = this;
    lblEdit.BorderStyle = BorderStyle.Fixed3D;
    lblEdit.Location = new Point(cmb.Left, cmb.Bottom + 10);
    lblEdit.BackColor = Color.LightGray;
    lblEdit.Text = "";
    lblEdit.Size = new Size(cmb.DropDownWidth, Font.Height * 2);
    btnDisplay = new Button();
    btnDisplay.Parent = this;
    btnDisplay.Text = "&Display Items";
    btnDisplay.Size = new Size((int)(Font.Height * .75) * btnDisplay.Text.Length, cmb.Height);
    btnDisplay.Location = new Point(lblEdit.Left, lblEdit.Bottom + 10);
    btnDisplay.Click += new System.EventHandler(btnDisplay_Click);
    txtDisplay = new TextBox();
    txtDisplay.Parent = this;
    txtDisplay.Location = new Point(btnDisplay.Left, btnDisplay.Bottom + 10);
    txtDisplay.Multiline = true;
    txtDisplay.ReadOnly = true;
    txtDisplay.BackColor = Color.LightGray;
    txtDisplay.ScrollBars = ScrollBars.Vertical;
    txtDisplay.Text = "";
    txtDisplay.Size = new Size(cmb.DropDownWidth, 200);
    
    btnSelect = new Button();
    btnSelect.Parent = this;
    btnSelect.Text = "&Select 4";
    btnSelect.Size = new Size((int)(Font.Height * .75) * btnSelect.Text.Length, cmb.Height);
    btnSelect.Location = new Point(btnDisplay.Right + 10, btnDisplay.Top);
    btnSelect.Click += new System.EventHandler(btnSelect_Click);
      cmb.Items.Add("A");
      cmb.Items.Add("B");
      cmb.Items.Add("C");
      cmb.Items.Add("D");
      cmb.Items.Add("E");                        
    cmb.SelectedIndex = 0;   
  }
  static void Main() 
  {
    Application.Run(new ComboBoxes());
  }
  private void this_Load(object sender, EventArgs e)
  {
    cmb.TextChanged += new EventHandler(cmb_TextChanged);
    cmb.SelectedIndexChanged += new EventHandler(cmb_SelectedIndexChanged);
  }
  private void cmb_TextChanged(object sender, EventArgs e)
  {
    if (!boolProcessed)
      lblEdit.Text = cmb.Text;
    boolChange = true;
  }    
  private void cmb_SelectedIndexChanged(object sender, EventArgs e)
  {
    if (boolChange)
    {
      boolChange = false;
      boolProcessed = false;
    }
  }
  private void cmb_SelectionChangeCommitted(object sender, EventArgs e)
  {
    if (boolChange)
      ProcessChange();
  }    
  private void cmb_Leave(object sender, EventArgs e)
  {
    if (boolChange)
    {
      ProcessChange();
      boolChange = false;
    }
  }    
  private void ProcessChange()
  {
    lblEdit.Text = "Edited: " + cmb.Text;
    boolProcessed = true;
  }
  private void btnDisplay_Click(object sender, EventArgs e)
  {
    string str = DateTime.Now.ToString() + "\r\n";
    foreach (object item in cmb.Items)
    {
      str += item.ToString() + "\r\n";
    }
    txtDisplay.Text = str;
  }    
  private void btnSelect_Click(object sender, EventArgs e)
  {
    cmb.Select(1,2);
  }    
  private void btnInsert_Click(object sender, EventArgs e)
  {
    if (cmb.FindStringExact(cmb.Text) != -1)
    {
      MessageBox.Show(""" + cmb.Text + "" already exists in the list.\r\n" + 
          "Will not be added again.",
          "Already Exists!");
    }
    else if (cmb.Text == "")
    {
      MessageBox.Show("There is nothing to add.","Nothing There");
    }
    else
    {
      cmb.Items.Add(cmb.Text);
    }
  }
}


extends ComboBox

  
/*
Revised from cdoe 
Visual C# 2005 Recipes A Problem-Solution Approach
# By Allen Jones
Matthew MacDonald
Rakesh Rajan
# ISBN: 1590595890
# ISBN-13: 9781590595893
# 592 pp.
# Published: Jan 2006
*/
using System;
using System.IO;
using System.Drawing;
using System.Windows.Forms;
public partial class ComboBoxHolder : Form
{
    public ComboBoxHolder()
    {
        this.SuspendLayout();
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(292, 266);
        this.Name = "ComboBoxHolder";
        this.Text = "ComboBoxHolder";
        this.ResumeLayout(false);

    }
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        AutoCompleteComboBox combo = new AutoCompleteComboBox();
        combo.Location = new Point(10, 10);
        this.Controls.Add(combo);
        combo.Items.Add("word");
        combo.Items.Add("world");
        combo.Items.Add("wording");
        combo.Items.Add("worse");
        
    }
    [STAThread]
    public static void Main(string[] args)
    {
        Application.Run(new ComboBoxHolder());
    }
}
public class AutoCompleteComboBox : ComboBox
{
    private bool controlKey = false;
    protected override void OnKeyPress(System.Windows.Forms.KeyPressEventArgs e)
    {
        base.OnKeyPress(e);
        if (e.KeyChar == (int)Keys.Escape)
        {
            this.SelectedIndex = -1;
            this.Text = "";
            controlKey = true;
        } else if (Char.IsControl(e.KeyChar)) {
            controlKey = true;
        } else {
            controlKey = false;
        }
    }
    protected override void OnTextChanged(System.EventArgs e)
    {
        base.OnTextChanged(e);
        if (this.Text != "" && !controlKey)
        {
            string matchText = this.Text;
            int match = this.FindString(matchText);
            if (match != -1)
            {
                this.SelectedIndex = match;
                this.SelectionStart = matchText.Length;
                this.SelectionLength = this.Text.Length - this.SelectionStart;
            }
        }
    }
}