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LayoutEventArgs Class

Provides data for the Layout event. This class cannot be inherited.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)
public sealed class LayoutEventArgs : EventArgs

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 null 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 : 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();
   }

   protected override void Dispose( bool disposing )
   {
      if( disposing )
      {
         if (components != null) 
         {
            components.Dispose();
         }
      }
      base.Dispose( disposing );
   }

   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.Anchor = System.Windows.Forms.AnchorStyles.Bottom;
      this.layoutButton.Location = new System.Drawing.Point(72, 88);
      this.layoutButton.Name = "layoutButton";
      this.layoutButton.Size = new System.Drawing.Size(150, 23);
      this.layoutButton.TabIndex = 0;
      this.layoutButton.Text = "Hello";
      //  
      // textBox1 
      //  
      this.textBox1.Anchor = ((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
         | System.Windows.Forms.AnchorStyles.Right);
      this.textBox1.Location = new System.Drawing.Point(24, 40);
      this.textBox1.Name = "textBox1";
      this.textBox1.Size = new System.Drawing.Size(248, 20);
      this.textBox1.TabIndex = 1;
      this.textBox1.Text = "Hello";
      this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
      //  
      // label1 
      //  
      this.label1.Location = new System.Drawing.Point(24, 16);
      this.label1.Name = "label1";
      this.label1.TabIndex = 2;
      this.label1.Text = "Button\'s Text:";
      //  
      // Form1 
      //  
      this.ClientSize = new System.Drawing.Size(292, 129);
      this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                   this.label1,
                                                                   this.textBox1,
                                                                   this.layoutButton});
      this.Name = "Form1";
      this.Text = "Layout Sample";
      this.Layout += new System.Windows.Forms.LayoutEventHandler(this.Form1_Layout);
      this.ResumeLayout(false);

   }

   [STAThread]
   static void Main() 
   {
      Application.Run(new Form1());
   }

   // 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.AffectedControl != null) && (e.AffectedProperty != null))
      {
         // Ensure that the affected property is the Bounds property 
         // of the form. 
         if (e.AffectedProperty.ToString() == "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.Width + 50) > 300) 
            {
               this.Width = this.layoutButton.Width + 50;
            }
               // If not, keep the form's width at 300 pixels. 
            else 
            {
               this.Width = 300;
            }

            // Center layoutButton on the form. 
            this.layoutButton.Left = (this.ClientSize.Width - this.layoutButton.Width) / 2;
         }
      }
   }

   // 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.Text = this.textBox1.Text;
      // Get the width of the text using the proper font. 
      int textWidth = (int)this.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)
      {
         // Setting the size property on any control raises  
         // the Layout event for its container. 
         this.layoutButton.Width = textWidth + 20;
      }
         // If not, keep layoutButton's width at 150 pixels. 
      else 
      {
         this.layoutButton.Width = 150;
      }
   }
}
System.Object
  System.EventArgs
    System.Windows.Forms.LayoutEventArgs
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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