Csharp/CSharp Tutorial/GUI Windows Forms/Control Event
Cancel (eat) event
<source lang="csharp">using System; using System.Drawing; using System.Collections; using System.ruponentModel; using System.Windows.Forms; using System.Data; public class TextCancelEventKeyEvent : System.Windows.Forms.Form {
private System.Windows.Forms.Label label1; private System.Windows.Forms.TextBox txtInput; private System.Windows.Forms.Label label2; private System.Windows.Forms.Label lblTrue; private System.Windows.Forms.Label label3; private System.Windows.Forms.Label lblCheck; private System.Windows.Forms.Label lblResults; public TextCancelEventKeyEvent() { InitializeComponent(); } private void InitializeComponent() { this.label1 = new System.Windows.Forms.Label(); this.txtInput = new System.Windows.Forms.TextBox(); this.label2 = new System.Windows.Forms.Label(); this.lblTrue = new System.Windows.Forms.Label(); this.label3 = new System.Windows.Forms.Label(); this.lblCheck = new System.Windows.Forms.Label(); this.lblResults = new System.Windows.Forms.Label(); this.SuspendLayout(); // // label1 // this.label1.Font = new System.Drawing.Font("Tahoma", 14.25F, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic), System.Drawing.GraphicsUnit.Point, ((System.Byte)(0))); this.label1.Location = new System.Drawing.Point(48, 16); this.label1.Name = "label1"; this.label1.Size = new System.Drawing.Size(176, 23); this.label1.TabIndex = 0; this.label1.Text = "ISBN Validation"; // // txtInput // this.txtInput.Location = new System.Drawing.Point(72, 64); this.txtInput.Name = "txtInput"; this.txtInput.TabIndex = 1; this.txtInput.Text = ""; this.txtInput.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.txtInput_KeyPress); this.txtInput.Validating += new System.ruponentModel.CancelEventHandler(this.handleCancleEvent); // // label2 // this.label2.Location = new System.Drawing.Point(24, 104); this.label2.Name = "label2"; this.label2.Size = new System.Drawing.Size(80, 23); this.label2.TabIndex = 2; this.label2.Text = "True Number:"; // // lblTrue // this.lblTrue.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.lblTrue.Location = new System.Drawing.Point(112, 104); this.lblTrue.Name = "lblTrue"; this.lblTrue.TabIndex = 3; // // label3 // this.label3.Location = new System.Drawing.Point(32, 152); this.label3.Name = "label3"; this.label3.Size = new System.Drawing.Size(72, 23); this.label3.TabIndex = 4; this.label3.Text = "Check Digit:"; // // lblCheck // this.lblCheck.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.lblCheck.Location = new System.Drawing.Point(112, 152); this.lblCheck.Name = "lblCheck"; this.lblCheck.TabIndex = 5; // // lblResults // this.lblResults.Location = new System.Drawing.Point(56, 192); this.lblResults.Name = "lblResults"; this.lblResults.Size = new System.Drawing.Size(152, 24); this.lblResults.TabIndex = 8; // // TextCancelEventKeyEvent // this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.ClientSize = new System.Drawing.Size(264, 293); this.Controls.AddRange(new System.Windows.Forms.Control[] { this.lblResults, this.lblCheck, this.label3, this.lblTrue, this.label2, this.txtInput, this.label1}); this.ResumeLayout(false); } [STAThread] static void Main() { Application.Run(new TextCancelEventKeyEvent()); } private void handleCancleEvent(object sender, System.ruponentModel.CancelEventArgs e) { TextBox tb = (TextBox)sender; string strInput = tb.Text; Console.WriteLine(strInput); } private void txtInput_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e) { char keyChar; keyChar = e.KeyChar; if(!Char.IsDigit(keyChar) // 0 - 9 && keyChar != 8 // backspace && keyChar != 13 // enter && keyChar != "x" && keyChar != 45 // dash/minus ){ // Do not display the keystroke e.Handled = true; } }
}</source>
Label"s Generic event
<source lang="csharp">using System; using System.Drawing; using System.Collections; using System.ruponentModel; using System.Windows.Forms; using System.Data; public class LabelWithGenericEvent : System.Windows.Forms.Form {
private System.Windows.Forms.Label lblTitle; public LabelWithGenericEvent() { InitializeComponent(); } private void InitializeComponent() { this.lblTitle = new System.Windows.Forms.Label(); this.SuspendLayout(); // // lblTitle // this.lblTitle.Location = new System.Drawing.Point(40, 24); this.lblTitle.Name = "lblTitle"; this.lblTitle.Size = new System.Drawing.Size(150, 25); this.lblTitle.TabIndex = 0; this.lblTitle.Text = "Events Demonstrator"; this.lblTitle.Click += new System.EventHandler(this.GenericEventHandler); this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.ClientSize = new System.Drawing.Size(242, 173); this.Controls.AddRange(new System.Windows.Forms.Control[] { this.lblTitle}); this.ResumeLayout(false); } [STAThread] static void Main() { Application.Run(new LabelWithGenericEvent()); } private void GenericEventHandler(object sender, EventArgs e) { MessageBox.Show("Generic event handler","Event Demo"); }
}</source>