Bitmap::GetHicon Method ()

 

Returns the handle to an icon.

Namespace:   System.Drawing
Assembly:  System.Drawing (in System.Drawing.dll)

public:
[SecurityPermissionAttribute(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::UnmanagedCode)]
IntPtr GetHicon()

Return Value

Type: System::IntPtr

A Windows handle to an icon with the same image as the Bitmap.

Exception Condition
Exception

The operation failed.

Initially, an icon created from the handle will have the same size as the original bitmap.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the Paint event handler. The code performs the following actions:

  • Creates a Bitmap.

  • Draws that object to the screen.

  • Gets an icon handle for the Bitmap.

  • Sets the Form::Icon attribute of the form to an icon created from the handle.

private:
   [System::Runtime::InteropServices::DllImportAttribute("user32.dll",CharSet=CharSet::Auto)]
   static bool DestroyIcon( IntPtr handle );

private:
   [SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
   void GetHicon_Example( PaintEventArgs^ e )
   {

      // Create a Bitmap object from an image file.
      Bitmap^ myBitmap = gcnew Bitmap( "c:\\FakePhoto.jpg" );

      // Draw myBitmap to the screen.
      e->Graphics->DrawImage( myBitmap, 0, 0 );

      // Get an Hicon for myBitmap.
      IntPtr Hicon = myBitmap->GetHicon();

      // Create a new icon from the handle. 
      System::Drawing::Icon^ newIcon = ::Icon::FromHandle( Hicon );

      // Set the form Icon attribute to the new icon.
      this->Icon = newIcon;

      // You can now destroy the Icon, since the form creates
      // its own copy of the icon accesible through the Form.Icon property.
      DestroyIcon( newIcon->Handle );
   }

SecurityPermission

for calling into unmanaged code. Related enumeration: UnmanagedCode

.NET Framework
Available since 1.1
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