如何：呈现视觉样式元素

更新：2007 年 11 月

System.Windows.Forms.VisualStyles 命名空间公开了表示由视觉样式支持的 Windows 用户界面 (UI) 元素的 VisualStyleElement 对象。本主题演示如何使用 VisualStyleRenderer 类呈现表示“开始”菜单中的“注销”和“关机”按钮的 VisualStyleElement。

呈现视觉样式元素

1. 创建一个 VisualStyleRenderer 并将其设置为您想绘制的元素。请注意 Application.RenderWithVisualStyles 属性和 VisualStyleRenderer.IsElementDefined 方法的使用；如果视觉样式被禁用或某个元素未定义，则 VisualStyleRenderer 构造函数将引发异常。

   Private renderer As VisualStyleRenderer = Nothing
   Private element As VisualStyleElement = _
       VisualStyleElement.StartPanel.LogOffButtons.Normal
   
   Public Sub New()
       Me.Location = New Point(50, 50)
       Me.Size = New Size(200, 200)
       Me.BackColor = SystemColors.ActiveBorder
   
       If Application.RenderWithVisualStyles And _
           VisualStyleRenderer.IsElementDefined(element) Then
               renderer = New VisualStyleRenderer(element)
       End If
   End Sub
   

   private VisualStyleRenderer renderer = null;
   private readonly VisualStyleElement element =
       VisualStyleElement.StartPanel.LogOffButtons.Normal;
   
   public CustomControl()
   {
       this.Location = new Point(50, 50);
       this.Size = new Size(200, 200);
       this.BackColor = SystemColors.ActiveBorder;
   
       if (Application.RenderWithVisualStyles &&
           VisualStyleRenderer.IsElementDefined(element))
       {
           renderer = new VisualStyleRenderer(element);
       }
   }
   

   private:
       VisualStyleRenderer^ renderer;
       VisualStyleElement^ element;
   
   public:
       CustomControl()
       {
           this->Location = Point(50, 50);
           this->Size = System::Drawing::Size(200, 200);
           this->BackColor = SystemColors::ActiveBorder;
           this->element = 
               VisualStyleElement::StartPanel::LogOffButtons::Normal;
           if (Application::RenderWithVisualStyles &&
               VisualStyleRenderer::IsElementDefined(element))
           {
               renderer = gcnew VisualStyleRenderer(element);
           }
       }
   

2. 调用 DrawBackground 方法呈现 VisualStyleRenderer 当前所表示的元素。

   Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
       ' Draw the element if the renderer has been set.
       If (renderer IsNot Nothing) Then
           renderer.DrawBackground(e.Graphics, Me.ClientRectangle)
   
       ' Visual styles are disabled or the element is undefined, 
       ' so just draw a message.
       Else
           Me.Text = "Visual styles are disabled."
           TextRenderer.DrawText(e.Graphics, Me.Text, Me.Font, _
               New Point(0, 0), Me.ForeColor)
       End If
   End Sub
   

   protected override void OnPaint(PaintEventArgs e)
   {
       // Draw the element if the renderer has been set.
       if (renderer != null)
       {
           renderer.DrawBackground(e.Graphics, this.ClientRectangle);
       }
   
       // Visual styles are disabled or the element is undefined, 
       // so just draw a message.
       else
       {
           this.Text = "Visual styles are disabled.";
           TextRenderer.DrawText(e.Graphics, this.Text, this.Font,
               new Point(0, 0), this.ForeColor);
       }
   }
   

   protected:
       virtual void OnPaint(PaintEventArgs^ e) override
       {
           // Draw the element if the renderer has been set.
           if (renderer != nullptr)
           {
               renderer->DrawBackground(e->Graphics, this->ClientRectangle);
           }
   
           // Visual styles are disabled or the element is undefined,
           // so just draw a message.
           else
           {
               this->Text = "Visual styles are disabled.";
               TextRenderer::DrawText(e->Graphics, this->Text, this->Font,
                   Point(0, 0), this->ForeColor);
           }
       }
   

编译代码

此示例需要：

• 派生自 Control 类的自定义控件。

• 承载该自定义控件的 Form。

• 对 System、System.Drawing、System.Windows.Forms 和 System.Windows.Forms.VisualStyles 命名空间的引用。

请参见

概念

使用视觉样式呈现控件