LayoutEventArgs Class


The .NET API Reference documentation has a new home. Visit the .NET API Browser on to see the new experience.

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

System_CAPS_pubmethodLayoutEventArgs(Control, String)

Initializes a new instance of the LayoutEventArgs class with the specified control and property affected.

System_CAPS_pubmethodLayoutEventArgs(IComponent, String)

Initializes a new instance of the LayoutEventArgs class with the specified component and property affected.


Gets the Component affected by the layout change.


Gets the child control affected by the change.


Gets the property affected by the change.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Returns a string that represents the current object.(Inherited from Object.)

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 Handling and Raising 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()

   protected override void Dispose( bool disposing )
      if( disposing )
         if (components != null) 
      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();
      // 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.Name = "Form1";
      this.Text = "Layout Sample";
      this.Layout += new System.Windows.Forms.LayoutEventHandler(this.Form1_Layout);


   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.
               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.
         this.layoutButton.Width = 150;

.NET Framework
Available since 1.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Return to top