TrackBarRenderer.GetTopPointingThumbSize(Graphics, TrackBarThumbState) 方法

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

返回指向上方的跟踪条滑块（又称滚动块）的大小，以像素为单位。

public:
 static System::Drawing::Size GetTopPointingThumbSize(System::Drawing::Graphics ^ g, System::Windows::Forms::VisualStyles::TrackBarThumbState state);

public static System.Drawing.Size GetTopPointingThumbSize (System.Drawing.Graphics g, System.Windows.Forms.VisualStyles.TrackBarThumbState state);

static member GetTopPointingThumbSize : System.Drawing.Graphics * System.Windows.Forms.VisualStyles.TrackBarThumbState -> System.Drawing.Size

Public Shared Function GetTopPointingThumbSize (g As Graphics, state As TrackBarThumbState) As Size

参数

g

Graphics

此操作将使用的 Graphics。

state

TrackBarThumbState

TrackBarThumbState 值之一，指定滑块的可视状态。

返回

Size

一个 Size，以像素为单位指定滑块的大小。

例外

InvalidOperationException

操作系统不支持视觉样式。

• 或 -

用户在操作系统中禁用视觉样式。

• 或 -

视觉样式不应用于应用程序窗口的工作区。

示例

下面的代码示例使用 GetTopPointingThumbSize 该方法来确定该方法用于 DrawTopPointingThumb 绘制滑块的矩形的大小。 此代码示例是为类提供的大型示例的 TrackBarRenderer 一部分。

    // Calculate the sizes of the bar, thumb, and ticks rectangle.
private:
    void SetupTrackBar()
    {
        if (!TrackBarRenderer::IsSupported)
        {
            return;
        }

        Graphics^ g = this->CreateGraphics();

        // Calculate the size of the track bar.
        trackRectangle.X = ClientRectangle.X + 2;
        trackRectangle.Y = ClientRectangle.Y + 28;
        trackRectangle.Width = ClientRectangle.Width - 4;
        trackRectangle.Height = 4;

        // Calculate the size of the rectangle in which to
        // draw the ticks.
        ticksRectangle.X = trackRectangle.X + 4;
        ticksRectangle.Y = trackRectangle.Y - 8;
        ticksRectangle.Width = trackRectangle.Width - 8;
        ticksRectangle.Height = 4;

        tickSpace = ((float)ticksRectangle.Width - 1) /
            ((float)numberTicks - 1);

        // Calculate the size of the thumb.
        thumbRectangle.Size =
            TrackBarRenderer::GetTopPointingThumbSize(g,
            TrackBarThumbState::Normal);

        thumbRectangle.X = CurrentTickXCoordinate();
        thumbRectangle.Y = trackRectangle.Y - 8;
    }

// Calculate the sizes of the bar, thumb, and ticks rectangle.
private void SetupTrackBar()
{
    if (!TrackBarRenderer.IsSupported)
        return;

    using (Graphics g = this.CreateGraphics())
    {
        // Calculate the size of the track bar.
        trackRectangle.X = ClientRectangle.X + 2;
        trackRectangle.Y = ClientRectangle.Y + 28;
        trackRectangle.Width = ClientRectangle.Width - 4;
        trackRectangle.Height = 4;

        // Calculate the size of the rectangle in which to 
        // draw the ticks.
        ticksRectangle.X = trackRectangle.X + 4;
        ticksRectangle.Y = trackRectangle.Y - 8;
        ticksRectangle.Width = trackRectangle.Width - 8;
        ticksRectangle.Height = 4;

        tickSpace = ((float)ticksRectangle.Width - 1) /
            ((float)numberTicks - 1);

        // Calculate the size of the thumb.
        thumbRectangle.Size =
            TrackBarRenderer.GetTopPointingThumbSize(g,
            TrackBarThumbState.Normal);

        thumbRectangle.X = CurrentTickXCoordinate();
        thumbRectangle.Y = trackRectangle.Y - 8;
    }
}

' Calculate the sizes of the bar, thumb, and ticks rectangle.
Private Sub SetupTrackBar()
    If Not TrackBarRenderer.IsSupported Then
        Return
    End If
    Using g As Graphics = Me.CreateGraphics()
        ' Calculate the size of the track bar.
        trackRectangle.X = ClientRectangle.X + 2
        trackRectangle.Y = ClientRectangle.Y + 28
        trackRectangle.Width = ClientRectangle.Width - 4
        trackRectangle.Height = 4

        ' Calculate the size of the rectangle in which to 
        ' draw the ticks.
        ticksRectangle.X = trackRectangle.X + 4
        ticksRectangle.Y = trackRectangle.Y - 8
        ticksRectangle.Width = trackRectangle.Width - 8
        ticksRectangle.Height = 4

        tickSpace = (CSng(ticksRectangle.Width) - 1) / _
            (CSng(numberTicks) - 1)

        ' Calculate the size of the thumb.
        thumbRectangle.Size = _
            TrackBarRenderer.GetTopPointingThumbSize( _
            g, TrackBarThumbState.Normal)

        thumbRectangle.X = CurrentTickXCoordinate()
        thumbRectangle.Y = trackRectangle.Y - 8
    End Using
End Sub

注解

滑块的大小由操作系统的当前视觉样式决定。

在调用此方法之前，应验证属性的值 IsSupported 是否为 true。