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 Handling and Raising Events.

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
Available since 1.1
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