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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:
property String^ AffectedProperty {
	String^ 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 nullptr 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 ref class Form1: public System::Windows::Forms::Form
{
private:
   System::Windows::Forms::TextBox^ textBox1;
   System::Windows::Forms::Label ^ label1;
   System::Windows::Forms::Button^ layoutButton;
   System::ComponentModel::Container^ components;

public:
   Form1()
   {
      InitializeComponent();
   }

protected:
   ~Form1()
   {
      if ( components != nullptr )
      {
         delete components;
      }
   }

private:
   void InitializeComponent()
   {
      this->layoutButton = gcnew System::Windows::Forms::Button;
      this->textBox1 = gcnew System::Windows::Forms::TextBox;
      this->label1 = gcnew System::Windows::Forms::Label;
      this->SuspendLayout();

      //  
      // layoutButton 
      //  
      this->layoutButton->Anchor = System::Windows::Forms::AnchorStyles::Bottom;
      this->layoutButton->Location = System::Drawing::Point( 72, 88 );
      this->layoutButton->Name = "layoutButton";
      this->layoutButton->Size = System::Drawing::Size( 150, 23 );
      this->layoutButton->TabIndex = 0;
      this->layoutButton->Text = "Hello";

      //  
      // textBox1 
      //  
      this->textBox1->Anchor = static_cast<System::Windows::Forms::AnchorStyles>(System::Windows::Forms::AnchorStyles::Top | System::Windows::Forms::AnchorStyles::Left | System::Windows::Forms::AnchorStyles::Right);
      this->textBox1->Location = System::Drawing::Point( 24, 40 );
      this->textBox1->Name = "textBox1";
      this->textBox1->Size = System::Drawing::Size( 248, 20 );
      this->textBox1->TabIndex = 1;
      this->textBox1->Text = "Hello";
      this->textBox1->TextChanged += gcnew System::EventHandler( this, &Form1::textBox1_TextChanged );

      //  
      // label1 
      //  
      this->label1->Location = System::Drawing::Point( 24, 16 );
      this->label1->Name = "label1";
      this->label1->TabIndex = 2;
      this->label1->Text = "Button's Text:";

      //  
      // Form1 
      //  
      this->ClientSize = System::Drawing::Size( 292, 129 );
      array<System::Windows::Forms::Control^>^temp0 = {this->label1,this->textBox1,this->layoutButton};
      this->Controls->AddRange( temp0 );
      this->Name = "Form1";
      this->Text = "Layout Sample";
      this->Layout += gcnew System::Windows::Forms::LayoutEventHandler( this, &Form1::Form1_Layout );
      this->ResumeLayout( false );
   }

   // 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. 
   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 != nullptr) && (e->AffectedProperty != nullptr) )
      {
         // Ensure that the affected property is the Bounds property 
         // of the form. 
         if ( e->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->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. 
   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;
      }
   }
};

[STAThread]
int main()
{
   Application::Run( gcnew Form1 );
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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