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LayoutEventHandler Delegate
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LayoutEventHandler Delegate

Represents the method that will handle the Layout event of a Control.

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

public delegate void LayoutEventHandler(
	Object^ sender, 
	LayoutEventArgs^ e
)

Parameters

sender
Type: System::Object
The source of the event.
e
Type: System.Windows.Forms::LayoutEventArgs
A LayoutEventArgs that contains the event data.

When you create a LayoutEventArgs delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Events and Delegates.


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, 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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