矩形孔尺寸不等于我电脑屏幕上的真实鼠标位置

Question

我在网上搜索过如何在 Form 上画一个矩形孔，我发现 this 用 Delphi 语言写的很好的例子，然后我尝试在 VB.NET 中重现这个例子, 直到现在我已经成功地在窗体上绘制了矩形孔，但是这个矩形的尺寸与我电脑屏幕上的真实鼠标位置不对应

并且相对于 Delphi 示例，我的示例难以适应 ClientToScreen 函数，这可能是解决此问题的方法。

有人可以帮我解决这个问题吗？

这是我最后一次尝试：

 <DllImport("user32.dll")> _
    Private Shared Function ClientToScreen(ByVal hWnd As IntPtr, ByRef lpPoint As Point) As Boolean
    End Function

    Dim mRect As Rectangle

    Private Sub Form1_MouseDown(sender As Object, e As MouseEventArgs) Handles MyBase.MouseDown
        mRect = New Rectangle(e.X, e.Y, 0, 0)
        Me.Invalidate()
    End Sub

    Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)

        If e.Button = Windows.Forms.MouseButtons.Left Then

            Dim gp As New System.Drawing.Drawing2D.GraphicsPath

            gp.AddRectangle(New Rectangle(0, 0, Me.Width, Me.Height))

            mRect = New Rectangle(mRect.Left, mRect.Top, e.X - mRect.Left, e.Y - mRect.Top)

            gp.AddRectangle(mRect)

            Me.Region = New Region(gp)

            Me.Invalidate()
        End If
    End Sub

    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        Using pen As New Pen(Color.Red, 3)
            e.Graphics.DrawRectangle(pen, mRect)
        End Using
    End Sub

产生以下结果：result

Answer 1

选项 1

您可以使用Me.PointToClient(Me.Location)计算窗体左上点和其客户区左上点之间的距离，并在您要计算位置时使用它：

代码

Public Class HoleForm
    Dim mRect As Rectangle
    Dim d
    Private Sub Form1_MouseDown(sender As Object, e As MouseEventArgs) Handles MyBase.MouseDown
        mRect = New Rectangle(e.X - d.x, e.Y - d.y, 0, 0)
        Me.Invalidate()
    End Sub

    Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)

        If e.Button = Windows.Forms.MouseButtons.Left Then

            Dim gp As New System.Drawing.Drawing2D.GraphicsPath

            gp.AddRectangle(New Rectangle(0, 0, Me.Width, Me.Height))

            mRect = New Rectangle(mRect.Left, mRect.Top, e.X - d.x - mRect.Left, e.Y - d.y - mRect.Top)

            gp.AddRectangle(mRect)

            Me.Region = New Region(gp)

            Me.Invalidate()
        End If
    End Sub

    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        Dim mRect2 = New Rectangle(mRect.Location, mRect.Size)
        mRect2.Offset(d)
        Using pen As New Pen(Color.Red, 3)
            e.Graphics.DrawRectangle(pen, mRect2)
        End Using
    End Sub

    Private Sub HoleForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        d = Me.PointToClient(Me.Location)
    End Sub
End Class

截图

选项2

您可以使用Me.TransparencyKey= Color.Red并用红色填充矩形，然后它就是您期望的洞。

代码

Public Class HoleForm
    Public Sub New()

        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        Me.TransparencyKey = Color.Red
    End Sub
    Dim mRect As Rectangle
    Protected Overrides Sub OnMouseDown(e As MouseEventArgs)
        mRect = New Rectangle(e.X, e.Y, 0, 0)
        Me.Invalidate()
        MyBase.OnMouseDown(e)
    End Sub
    Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)

        If e.Button = Windows.Forms.MouseButtons.Left Then
            mRect = New Rectangle(mRect.Left, mRect.Top, e.X - mRect.Left, e.Y - mRect.Top)
            Me.Invalidate()
        End If
    End Sub

    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        Using HoleBrush As New SolidBrush(Me.TransparencyKey)
            e.Graphics.FillRectangle(HoleBrush, mRect)
        End Using
        Using BorderPen As New Pen(Color.Blue, 3)
            e.Graphics.DrawRectangle(BorderPen, mRect)
        End Using
    End Sub
End Class

截图

矩形孔尺寸不等于我电脑屏幕上的真实鼠标位置

Rectangular hole dimensions isn't equals to real mouse position on my computer screen

vb.net

winforms

mouse-position

选项 1

选项2