InkCollectorMouseDownEventHandler 委托

项目
11/04/2008

表示处理 InkCollector 对象的 MouseDown 事件的方法。

命名空间： Microsoft.Ink
程序集： Microsoft.Ink（在 Microsoft.Ink.dll 中）

语法

声明
Public Delegate Sub InkCollectorMouseDownEventHandler ( _
    sender As Object, _
    e As CancelMouseEventArgs _
)
用法
Dim instance As New InkCollectorMouseDownEventHandler(AddressOf HandlerMethod)

public delegate void InkCollectorMouseDownEventHandler(
    Object sender,
    CancelMouseEventArgs e
)

public delegate void InkCollectorMouseDownEventHandler(
    Object^ sender, 
    CancelMouseEventArgs^ e
)

/** @delegate */
public delegate void InkCollectorMouseDownEventHandler(
    Object sender,
    CancelMouseEventArgs e
)

JScript 不支持委托。

参数

sender
类型：System.Object
此事件的源 InkCollector 对象。

e
类型：Microsoft.Ink.CancelMouseEventArgs
包含事件数据的 CancelMouseEventArgs 对象。

备注

创建 InkCollectorMouseDownEventHandler 委托时，需要标识将处理该事件的方法。若要将该事件与事件处理程序关联，请将该委托的一个实例添加到事件中。除非移除了该委托，否则每当发生该事件时就会调用此事件处理程序。出于性能方面的原因，默认事件关注在托管代码 中处于关闭状态，但如果添加事件处理程序，它将自动打开。

若要提高实时墨迹性能，请在墨迹书写时隐藏鼠标光标。为此，请在 MouseDown 事件处理程序中隐藏鼠标光标，并在 MouseUp 事件处理程序中显示鼠标光标。

备注

某些控件依赖于 MouseDown、MouseMove 和 MouseUp 事件之间的特定关系。取消这些事件可能获得意外的结果。

示例

在此示例中，当 MouseDown 事件激发时，将检查 EditingMode 是否设置为 Select。如果是，则调用 HitTestSelection 方法来确定已命中哪部分所选内容（如果有）。如果命中发生在由 SelectionHitResult 枚举所指定的四个主要罗盘方向的任一方向上，则所选择的笔画对象更改为另一种颜色。

Private Sub mInkObject_MouseDown(ByVal sender As Object, ByVal e As CancelMouseEventArgs)

    If InkOverlayEditingMode.Select = mInkObject.EditingMode Then
        Select Case mInkObject.HitTestSelection(e.X, e.Y)
            Case SelectionHitResult.North
                ChangeSelectionColor(Color.Green)
            Case SelectionHitResult.East
                ChangeSelectionColor(Color.Red)
            Case SelectionHitResult.South
                ChangeSelectionColor(Color.Purple)
            Case SelectionHitResult.West
                ChangeSelectionColor(Color.Blue)
        End Select
    End If
End Sub

Private Sub ChangeSelectionColor(ByVal color As Color)
    Dim DA As DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone()
    DA.Color = color
    mInkObject.Selection.ModifyDrawingAttributes(DA)
    Using G As Graphics = CreateGraphics()
        ' Get the bounding box of the selection. The default is
        ' to include the width of the strokes in the calculation.
        ' The returned rectangle is measured in ink units.
        Dim rInkUnits As Rectangle = mInkObject.Selection.GetBoundingBox()

        ' In selection mode, the selected strokes are drawn inflated
        ' GetBoundingBox() does not take this into account
        ' Rectangle rInkUnits is inflated to compensate
        rInkUnits.Inflate(53, 53)

        Dim topLeft As Point = rInkUnits.Location
        Dim bottomRight As Point = rInkUnits.Location + rInkUnits.Size

        ' get a Renderer object to make the conversion
        Dim R As Renderer = New Renderer()

        ' convert the points to pixels
        R.InkSpaceToPixel(G, topLeft)
        R.InkSpaceToPixel(G, bottomRight)

        ' create a rectangle that is in pixels
        Dim rPixelUnits As Rectangle = _
            New Rectangle(topLeft, New Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y))

        ' Redraw the strokes
        mInkObject.Draw(rPixelUnits)

    End Using
End Sub

private void mInkObject_MouseDown(object sender, CancelMouseEventArgs e)
{
    if (InkOverlayEditingMode.Select == mInkObject.EditingMode)
    {
        switch (mInkObject.HitTestSelection(e.X, e.Y))
        {
            case SelectionHitResult.North:
                ChangeSelectionColor(Color.Green);
                break;
            case SelectionHitResult.East:
                ChangeSelectionColor(Color.Red);
                break;
            case SelectionHitResult.South:
                ChangeSelectionColor(Color.Purple);
                break;
            case SelectionHitResult.West:
                ChangeSelectionColor(Color.Blue);
                break;
        }
    }
}

private void ChangeSelectionColor(Color color)
{
    DrawingAttributes DA = mInkObject.DefaultDrawingAttributes.Clone();
    DA.Color = color;
    mInkObject.Selection.ModifyDrawingAttributes(DA);
    using (Graphics G = CreateGraphics())
    {
        // Get the bounding box of the selection. The default is
        // to include the width of the strokes in the calculation.
        // The returned rectangle is measured in ink units.
        Rectangle rInkUnits = mInkObject.Selection.GetBoundingBox();

        // In selection mode, the selected strokes are drawn inflated
        // GetBoundingBox() does not take this into account
        // Rectangle rInkUnits is inflated to compensate
        rInkUnits.Inflate(53, 53);

        Point topLeft = rInkUnits.Location;
        Point bottomRight = rInkUnits.Location + rInkUnits.Size;

        // get a Renderer object to make the conversion
        Renderer R = new Renderer();

        // convert the points to pixels
        R.InkSpaceToPixel(G, ref topLeft);
        R.InkSpaceToPixel(G, ref bottomRight);

        // create a rectangle that is in pixels
        Rectangle rPixelUnits =
            new Rectangle(topLeft, new Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y));

        // Redraw the strokes
        mInkObject.Draw(rPixelUnits);

    } 
}