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LayoutEventArgs.AffectedProperty Property

Gets the property affected by the change.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public string AffectedProperty { get; }

Property Value

Type: System.String
The property affected by the change.

If a child control has been made visible since the last layout operation, the Visible property is affected. The AffectedProperty property is set to null if no value was provided when the PerformLayout method was called.

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;
      }
   }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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