StylusPlugIn.OnStylusDown(RawStylusInput) 方法

定义

命名空间:

System.Windows.Input.StylusPlugIns

程序集:

PresentationCore.dll

当触笔接触数字化仪时，在笔线程池中的线程上发生。

protected:
 virtual void OnStylusDown(System::Windows::Input::StylusPlugIns::RawStylusInput ^ rawStylusInput);

protected virtual void OnStylusDown (System.Windows.Input.StylusPlugIns.RawStylusInput rawStylusInput);

abstract member OnStylusDown : System.Windows.Input.StylusPlugIns.RawStylusInput -> unit
override this.OnStylusDown : System.Windows.Input.StylusPlugIns.RawStylusInput -> unit

Protected Overridable Sub OnStylusDown (rawStylusInput As RawStylusInput)

参数

rawStylusInput

RawStylusInput

一个包含有关笔输入信息的 RawStylusInput。

示例

下面的示例演示如何重写 OnStylusDown 方法。 若要创建将墨迹限制为特定区域的控件 StylusPlugIn ，请参阅 StylusPlugIn 概述。

protected override void OnStylusDown(RawStylusInput rawStylusInput)
{
    // Run the base class before modifying the data
    base.OnStylusDown(rawStylusInput);

    // Get the StylusPoints that have come in
    StylusPointCollection stylusPoints = rawStylusInput.GetStylusPoints();

    // Modify the (X,Y) data to move the points 
    // inside the acceptable input area, if necessary
    for (int i = 0; i < stylusPoints.Count; i++)
    {
        StylusPoint sp = stylusPoints[i];
        if (sp.X < 50) sp.X = 50;
        if (sp.X > 250) sp.X = 250;
        if (sp.Y < 50) sp.Y = 50;
        if (sp.Y > 250) sp.Y = 250;
        stylusPoints[i] = sp;
    }

    // Copy the modified StylusPoints back to the RawStylusInput
    rawStylusInput.SetStylusPoints(stylusPoints);
}

Protected Overrides Sub OnStylusDown(ByVal rawStylusInput As RawStylusInput) 
    ' Run the base class before we modify the data
    MyBase.OnStylusDown(rawStylusInput)
    
    ' Get the StylusPoints that have come in
    Dim stylusPoints As StylusPointCollection = rawStylusInput.GetStylusPoints()
    
    ' Modify the (X,Y) data to move the points 
    ' inside the acceptable input area, if necessary.
    Dim i As Integer

    For i = 0 To stylusPoints.Count - 1

        Dim sp As StylusPoint = stylusPoints(i)

        If sp.X < 50 Then
            sp.X = 50
        End If

        If sp.X > 250 Then
            sp.X = 250
        End If

        If sp.Y < 50 Then
            sp.Y = 50
        End If

        If sp.Y > 250 Then
            sp.Y = 250
        End If

        stylusPoints(i) = sp
    Next i
    
    ' Copy the modified StylusPoints back to the RawStylusInput
    rawStylusInput.SetStylusPoints(stylusPoints)

End Sub

注解

此方法在笔线程上发生，因此尽量减少此方法中的工作，以避免影响性能。