Icon.FromHandle(IntPtr) 方法

定义

从图标的指定 Windows 句柄 (Icon) 创建 GDI+ HICONCreates a GDI+ Icon from the specified Windows handle to an icon (HICON).

public:
 static System::Drawing::Icon ^ FromHandle(IntPtr handle);
public static System.Drawing.Icon FromHandle (IntPtr handle);
static member FromHandle : nativeint -> System.Drawing.Icon
Public Shared Function FromHandle (handle As IntPtr) As Icon

参数

handle
IntPtr

图标的 Windows 句柄。A Windows handle to an icon.

返回

Icon

此方法创建的 IconThe Icon this method creates.

示例

下面的代码示例旨在与 Windows 窗体一起使用,并且它需要作为 PaintEventArgs e Paint 事件处理程序的参数。The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the Paint event handler. 此代码执行以下操作:The code performs the following actions:

  • 创建一个 BitmapCreates a Bitmap.

  • 在屏幕上绘制该对象。Draws that object to the screen.

  • 获取的图标句柄 BitmapGets an icon handle for the Bitmap.

  • Form.Icon 窗体的属性设置为从该句柄创建的图标。Sets the Form.Icon attribute of the form to an icon created from the handle.

  • 调用 Windows API 函数 DestroyIcon 以释放资源。Calls the Windows API function DestroyIcon to release resources.

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 );
   }

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

private void GetHicon_Example(PaintEventArgs e)
{

    // Create a Bitmap object from an image file.
    Bitmap myBitmap = new 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. 
    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 accessible through the Form.Icon property.
    DestroyIcon(newIcon.Handle);
}
<System.Runtime.InteropServices.DllImportAttribute("user32.dll")> _
    Private Shared Function DestroyIcon(ByVal handle _ 
    As IntPtr) As Boolean 
    End Function

   Private Sub GetHicon_Example(ByVal e As PaintEventArgs)

        ' Create a Bitmap object from an image file.
        Dim myBitmap As New Bitmap("c:\FakePhoto.jpg")

        ' Draw myBitmap to the screen.
        e.Graphics.DrawImage(myBitmap, 0, 0)

        ' Get an Hicon for myBitmap.
        Dim HIcon As IntPtr = myBitmap.GetHicon()
    
        ' Create a new icon from the handle.
        Dim newIcon As Icon = System.Drawing.Icon.FromHandle(HIcon)

        ' Set the form Icon attribute to the new icon.
        Me.Icon = newIcon

        ' You can now destroy the icon, since the form creates its 
        ' own copy of the icon accessible through the Form.Icon property.
    DestroyIcon(newIcon.Handle)
    End Sub

注解

使用此方法时,必须使用 Windows API 中的方法释放原始图标, DestroyIcon 以确保释放资源。When using this method, you must dispose of the original icon by using the DestroyIcon method in the Windows API to ensure that the resources are released.

适用于