WorkflowDesignerMessageFilter.OnKeyDown(KeyEventArgs) 方法

protected:
 virtual bool OnKeyDown(System::Windows::Forms::KeyEventArgs ^ eventArgs);

protected virtual bool OnKeyDown (System.Windows.Forms.KeyEventArgs eventArgs);

abstract member OnKeyDown : System.Windows.Forms.KeyEventArgs -> bool
override this.OnKeyDown : System.Windows.Forms.KeyEventArgs -> bool

Protected Overridable Function OnKeyDown (eventArgs As KeyEventArgs) As Boolean

参数

返回

如果消息已处理，则为 true；否则为 false。

示例

下面的代码示例演示如何重写 OnKeyDown 方法，以便自定义从工作流设计图面中移除活动的方式。

此代码示例摘自 DesignerShell.cs 文件中的基本设计器宿主 SDK 示例。 有关详细信息，请参阅 Basic Designer Hosting。

protected override bool OnKeyDown(KeyEventArgs eventArgs)
{
    if (eventArgs.KeyCode == Keys.Delete)
    {
        ISelectionService selectionService = (ISelectionService)serviceProvider.GetService(typeof(ISelectionService));
        if (selectionService != null && selectionService.PrimarySelection is CodeActivity)
        {
            CodeActivity codeActivityComponent = (CodeActivity)selectionService.PrimarySelection;
            CompositeActivity parentActivity = codeActivityComponent.Parent;
            if (parentActivity != null)
            {
                parentActivity.Activities.Remove(codeActivityComponent);
                this.ParentView.Update();
            }
            loader.RemoveActivityFromDesigner(codeActivityComponent);
        }
    }
    return true;
}

Protected Overrides Function OnKeyDown(ByVal eventArgs As KeyEventArgs) As Boolean
    If eventArgs.KeyCode = Keys.Delete Then
        Dim selectionService As ISelectionService = CType(serviceProvider.GetService(GetType(ISelectionService)), ISelectionService)
        If selectionService IsNot Nothing AndAlso TypeOf selectionService.PrimarySelection Is CodeActivity Then
            Dim codeActivityComponent As CodeActivity = CType(selectionService.PrimarySelection, CodeActivity)
            Dim parentActivity As CompositeActivity = codeActivityComponent.Parent
            If parentActivity IsNot Nothing Then
                parentActivity.Activities.Remove(codeActivityComponent)
                Me.ParentView.Update()
            End If
            loader.RemoveActivityFromDesigner(codeActivityComponent)
        End If
    End If
    Return True
End Function

注解

在特定对象具有焦点的情况下按下某个键时发生 OnKeyDown。

适用于

另请参阅

• 基本Designer托管