MenuItem.DrawItem 事件
重要
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当菜单项的 OwnerDraw 属性设置为 true 并且发出绘制菜单项的请求时发生。
public:
event System::Windows::Forms::DrawItemEventHandler ^ DrawItem;C#
public event System.Windows.Forms.DrawItemEventHandler DrawItem;member this.DrawItem : System.Windows.Forms.DrawItemEventHandler Public Custom Event DrawItem As DrawItemEventHandler 下面的代码示例演示如何处理 DrawItem 事件。 此示例使用 Brush 和 Font绘制菜单项，然后在菜单项周围绘制 Rectangle 。 绘图通过 Graphics 对象执行，该对象将传递给 参数中的 DrawItemEventArgs 事件处理程序。 此示例要求已将项的 属性初始化 OwnerDraw 为 true。 对于 C# 示例，请在 窗体的构造函数的 后面 InitializeComponent添加以下代码，以挂接 事件：
this.menuItem1.DrawItem += new DrawItemEventHandler(menuItem1_DrawItem);
// The DrawItem event handler.
private:
void menuItem1_DrawItem( Object^ /*sender*/, System::Windows::Forms::DrawItemEventArgs^ e )
{
String^ myCaption = "Owner Draw Item1";
// Create a Brush and a Font with which to draw the item.
Brush^ myBrush = System::Drawing::Brushes::AliceBlue;
System::Drawing::Font^ myFont = gcnew System::Drawing::Font( FontFamily::GenericSerif,14,FontStyle::Underline,GraphicsUnit::Pixel );
SizeF mySizeF = e->Graphics->MeasureString( myCaption, myFont );
// Draw the item, and then draw a Rectangle around it.
e->Graphics->DrawString( myCaption, myFont, myBrush, (float)e->Bounds.X, (float)e->Bounds.Y );
e->Graphics->DrawRectangle( Pens::Black, Rectangle(e->Bounds.X,e->Bounds.Y,Convert::ToInt32( mySizeF.Width ),Convert::ToInt32( mySizeF.Height )) );
}
C#
// The DrawItem event handler.
private void menuItem1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
{
string myCaption = "Owner Draw Item1";
// Create a Brush and a Font with which to draw the item.
Brush myBrush = System.Drawing.Brushes.AliceBlue;
Font myFont = new Font(FontFamily.GenericSerif, 14, FontStyle.Underline, GraphicsUnit.Pixel);
SizeF mySizeF = e.Graphics.MeasureString(myCaption, myFont);
// Draw the item, and then draw a Rectangle around it.
e.Graphics.DrawString(myCaption, myFont, myBrush, e.Bounds.X, e.Bounds.Y);
e.Graphics.DrawRectangle(Pens.Black, new Rectangle(e.Bounds.X, e.Bounds.Y, Convert.ToInt32(mySizeF.Width), Convert.ToInt32(mySizeF.Height)));
}
' The DrawItem event handler.
Private Sub MenuItem1_DrawItem(ByVal sender As Object, ByVal e As System.Windows.Forms.DrawItemEventArgs) Handles MenuItem1.DrawItem
Dim MyCaption As String = "Owner Draw Item1"
' Create a Brush and a Font with which to draw the item.
Dim MyBrush As System.Drawing.Brush = System.Drawing.Brushes.AliceBlue
Dim MyFont As New Font(FontFamily.GenericSerif, 14, FontStyle.Underline, GraphicsUnit.Pixel)
Dim MySizeF As SizeF = e.Graphics.MeasureString(MyCaption, MyFont)
' Draw the item, and then draw a Rectangle around it.
e.Graphics.DrawString(MyCaption, MyFont, MyBrush, e.Bounds.X, e.Bounds.Y)
e.Graphics.DrawRectangle(Drawing.Pens.Black, New Rectangle(e.Bounds.X, e.Bounds.Y, MySizeF.Width, MySizeF.Height))
End Sub
DrawItemEventArgs传递给DrawItem事件处理程序的参数提供了一个 Graphics 对象，使你能够在菜单项的图面上执行绘图和其他图形操作。 可以使用此事件处理程序创建满足应用程序需求的自定义菜单。 有关处理事件的详细信息，请参阅 处理和引发事件。
| 产品 | 版本 |
|---|---|
| .NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| Windows Desktop | 3.0, 10 |
