LayoutEventArgs Class
Assembly: System.Windows.Forms (in system.windows.forms.dll)
Changes to a control such as resizing, showing or hiding child controls, and adding or removing child controls make it necessary for a control to layout its child controls. A LayoutEventArgs specifies the child control that has been changed and its affected property. For example, if a control has been made visible since the last layout operation, the Visible property is affected.
The AffectedControl and AffectedProperty properties are set to a null reference (Nothing in Visual Basic) if no values were provided when the PerformLayout method was called.
For more information about handling events, see Consuming Events.
The following code example uses the AffectedProperty and AffectedControl properties as LayoutEventHandler arguments to coordinate the size of a Windows form and its controls with various property changes to both the Windows form and the controls.
Public Class Form1 Inherits System.Windows.Forms.Form Private WithEvents textBox1 As System.Windows.Forms.TextBox Private label1 As System.Windows.Forms.Label Private layoutButton As System.Windows.Forms.Button Private components As System.ComponentModel.Container = Nothing Public Sub New() InitializeComponent() End Sub Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean) If disposing Then If Not (components Is Nothing) Then components.Dispose() End If End If MyBase.Dispose(disposing) End Sub Private Sub InitializeComponent() Me.layoutButton = New System.Windows.Forms.Button() Me.textBox1 = New System.Windows.Forms.TextBox() Me.label1 = New System.Windows.Forms.Label() Me.SuspendLayout() ' ' layoutButton ' Me.layoutButton.Anchor = System.Windows.Forms.AnchorStyles.Bottom Me.layoutButton.Location = New System.Drawing.Point(72, 88) Me.layoutButton.Name = "layoutButton" Me.layoutButton.Size = New System.Drawing.Size(150, 23) Me.layoutButton.TabIndex = 0 Me.layoutButton.Text = "Hello" ' ' textBox1 ' Me.textBox1.Anchor = System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left Or System.Windows.Forms.AnchorStyles.Right Me.textBox1.Location = New System.Drawing.Point(24, 40) Me.textBox1.Name = "textBox1" Me.textBox1.Size = New System.Drawing.Size(248, 20) Me.textBox1.TabIndex = 1 Me.textBox1.Text = "Hello" ' ' label1 ' Me.label1.Location = New System.Drawing.Point(24, 16) Me.label1.Name = "label1" Me.label1.TabIndex = 2 Me.label1.Text = "Button's Text:" ' ' Form1 ' Me.ClientSize = New System.Drawing.Size(292, 129) Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.label1, Me.textBox1, Me.layoutButton}) Me.Name = "Form1" Me.Text = "Layout Sample" Me.ResumeLayout(False) End Sub ' This method ensures that the form's width is the preferred size of 300 pixels ' or the size of the button plus 50 pixels, whichever amount is less. Private Sub Form1_Layout(ByVal sender As Object, ByVal e As System.Windows.Forms.LayoutEventArgs) Handles MyBase.Layout ' This event is raised once at startup with the AffectedControl ' and AffectedProperty properties on the LayoutEventArgs as null. ' The event provides size preferences for that case. If Not (e.AffectedControl Is Nothing) And Not (e.AffectedProperty Is Nothing) Then ' Ensure that the affected property is the Bounds property ' of the form. If e.AffectedProperty.ToString() = "Bounds" Then ' If layoutButton's width plus a padding of 50 pixels is greater than the preferred ' size of 300 pixels, increase the form's width. If Me.layoutButton.Width + 50 > 300 Then Me.Width = Me.layoutButton.Width + 50 ' If not, keep the form's width at 300 pixels. Else Me.Width = 300 End If ' Center layoutButton on the form. Me.layoutButton.Left = (Me.ClientSize.Width - Me.layoutButton.Width) / 2 End If End If End Sub ' This method sets the Text property of layoutButton to the Text property ' of textBox1. If the new text plus a padding of 20 pixels is larger than ' the preferred size of 150 pixels, increase layoutButton's Width property. Private Sub textBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles textBox1.TextChanged ' Set the Text property of layoutButton. Me.layoutButton.Text = Me.textBox1.Text ' Get the width of the text using the proper font. Dim textWidth As Integer = CInt(Me.CreateGraphics().MeasureString(layoutButton.Text, layoutButton.Font).Width) ' If the width of the text plus a padding of 20 pixels is greater than the preferred size of ' 150 pixels, increase layoutButton's width. If textWidth + 20 > 150 Then ' Setting the size property on any control raises ' the Layout event for its container. Me.layoutButton.Width = textWidth + 20 ' If not, keep layoutButton's width at 150 pixels. Else Me.layoutButton.Width = 150 End If End Sub End Class
public class Form1 extends System.Windows.Forms.Form
{
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Button layoutButton;
private System.ComponentModel.Container components = null;
public Form1()
{
InitializeComponent();
} //Form1
protected void Dispose(boolean disposing)
{
if (disposing) {
if (components != null) {
components.Dispose();
}
}
super.Dispose(disposing);
} //Dispose
private void InitializeComponent()
{
this.layoutButton = new System.Windows.Forms.Button();
this.textBox1 = new System.Windows.Forms.TextBox();
this.label1 = new System.Windows.Forms.Label();
this.SuspendLayout();
//
// layoutButton
//
this.layoutButton.set_Anchor(System.Windows.Forms.AnchorStyles.Bottom);
this.layoutButton.set_Location(new System.Drawing.Point(72, 88));
this.layoutButton.set_Name("layoutButton");
this.layoutButton.set_Size(new System.Drawing.Size(150, 23));
this.layoutButton.set_TabIndex(0);
this.layoutButton.set_Text("Hello");
//
// textBox1
//
this.textBox1.set_Anchor(System.Windows.Forms.AnchorStyles.Top
| System.Windows.Forms.AnchorStyles.Left | System.Windows.Forms.
AnchorStyles.Right);
this.textBox1.set_Location(new System.Drawing.Point(24, 40));
this.textBox1.set_Name("textBox1");
this.textBox1.set_Size(new System.Drawing.Size(248, 20));
this.textBox1.set_TabIndex(1);
this.textBox1.set_Text("Hello");
this.textBox1.add_TextChanged(new System.EventHandler(this.
textBox1_TextChanged));
//
// label1
//
this.label1.set_Location(new System.Drawing.Point(24, 16));
this.label1.set_Name("label1");
this.label1.set_TabIndex(2);
this.label1.set_Text("Button\'s Text:");
//
// Form1
//
this.set_ClientSize(new System.Drawing.Size(292, 129));
this.get_Controls().AddRange(new System.Windows.Forms.Control[] { this.
label1, this.textBox1, this.layoutButton });
this.set_Name("Form1");
this.set_Text("Layout Sample");
this.add_Layout(new System.Windows.Forms.LayoutEventHandler(this.
Form1_Layout));
this.ResumeLayout(false);
} //InitializeComponent
/** @attribute STAThread()
*/
public static void main(String[] args)
{
Application.Run(new Form1());
} //main
// This method ensures that the form's width is the preferred size of 300 pixels
// or the size of the button plus 50 pixels, whichever amount is less.
private void Form1_Layout(Object sender,
System.Windows.Forms.LayoutEventArgs e)
{
// This event is raised once at startup with the AffectedControl
// and AffectedProperty properties on the LayoutEventArgs as null.
// The event provides size preferences for that case.
if (e.get_AffectedControl() != null
&& e.get_AffectedProperty() != null) {
// Ensure that the affected property is the Bounds property
// of the form.
if ((e.get_AffectedProperty().ToString()).Equals("Bounds")) {
// If layoutButton's width plus a padding of 50 pixels is greater
// than the preferred size of 300 pixels, increase the form's width.
if (this.layoutButton.get_Width() + 50 > 300) {
this.set_Width(this.layoutButton.get_Width() + 50);
}
// If not, keep the form's width at 300 pixels.
else {
this.set_Width(300);
}
// Center layoutButton on the form.
this.layoutButton.set_Left((this.get_ClientSize().get_Width()
- this.layoutButton.get_Width()) / 2);
}
}
} //Form1_Layout
// This method sets the Text property of layoutButton to the Text property
// of textBox1. If the new text plus a padding of 20 pixels is larger than
// the preferred size of 150 pixels, increase layoutButton's Width property.
private void textBox1_TextChanged(Object sender, System.EventArgs e)
{
// Set the Text property of layoutButton.
this.layoutButton.set_Text(this.textBox1.get_Text());
// Get the width of the text using the proper font.
int textWidth = (int)(this.CreateGraphics().MeasureString(layoutButton.
get_Text(), layoutButton.get_Font()).get_Width());
// If the width of the text plus a padding of 20 pixels is greater than the preferred size of
// 150 pixels, increase layoutButton's width.
if (textWidth + 20 > 150){
// Setting the size property on any control raises
// the Layout event for its container.
this.layoutButton.set_Width(textWidth + 20);
}
// If not, keep layoutButton's width at 150 pixels.
else{
this.layoutButton.set_Width(150);
}
} //textBox1_TextChanged
} //Form1
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.