vb.netrect的简单介绍

vb.net中GetClientRect()函数的问题

对不起vb.netrect，vb.netrect我没有学过vb.netvb.netrect，但是学过vb，希望这个可以

解决您程序的毛病。首先您注意以下两种GetClientRect

声明的方法vb.netrect：

Option Explicit

Private Declare Function GetClientRect Lib "user32" ( _

ByVal hwnd As Long, _

ByRef lpRect As RECT _

) As Long

Private Type RECT

Left As Long

Top As Long

Right As Long

Bottom As Long

End Type

Private Sub Form_Load()

Dim r As RECT

Me.AutoRedraw = True

GetClientRect Me.hwnd, r

Print r.Left

Print r.Right

Print r.Top

Print r.Bottom

End Sub

----------------------------------------------------------------------------

Option Explicit

Private Declare Function GetClientRect Lib "user32" ( _

ByVal hwnd As Long, _

ByVal lpRect As Long _

) As Long

Private Type RECT

Left As Long

Top As Long

Right As Long

Bottom As Long

End Type

Private Sub Form_Load()

Dim r As RECT

Me.AutoRedraw = True

GetClientRect Me.hwnd, VarPtr(r)

Print r.Left

Print r.Right

Print r.Top

Print r.Bottom

End Sub

看出问题了没有，就在GetClientRect的第二个参数上：

一个是按地址传递，另一个是按值传递：

ByRef lpRect As RECT 用 GetClientRect Me.hwnd, r

ByVal lpRect As Long 用 GetClientRect Me.hwnd, VarPtr(r)

据我所知vb.net按值传递的比较多，应该用VarPtr获取RECT类型

(结构体)的指针，然后传递。

希望能对你有所帮助。

相关问答

Q1: VB.NET我要用鼠标轨迹画一个矩形框 然后选中控件。就像星际和魔兽争霸里对部队单位的选中一样~等大神回答

这个类继承自Panelvb.netrect，把它加到vb.netrect你vb.netrect的项目里面vb.netrect，先运行一下，然后从工具箱里把它拖到窗体上，然后再向里面添加其它控件就可以vb.netrect了，支持Shift加选，Alt减选

Imports System.Linq

Imports System.Collections

Public Class MyPanel

    Inherits Panel

    ' 选择模式，相交还是包含

    Enum SelectMode

        Intersects

        Contains

    End Enum

    Dim down As New Point(-1, -1)

    Dim rect As Rectangle

    Dim selected As New List(Of Control)

    Dim editting As IEnumerable(Of Control)

    Dim mode As SelectMode = SelectMode.Contains

    Dim shift, alt As Boolean

    Public Sub New()

        Me.DoubleBuffered = True

    End Sub

    Protected Overrides Sub OnMouseDown(e As MouseEventArgs)

        MyBase.OnMouseDown(e)

        down = e.Location

        editting = selected.ToArray().ToList()

        OnMouseMove(e)

    End Sub

    Protected Overrides Sub OnMouseMove(e As MouseEventArgs)

        MyBase.OnMouseMove(e)

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

            Dim loc As New Point(Math.Min(down.X, e.X), Math.Min(down.Y, e.Y))

            Dim size As New Size(Math.Abs(down.X - e.X), Math.Abs(down.Y - e.Y))

            rect = New Rectangle(loc, size)

            Dim cs As New List(Of Control)

            For Each c In Controls

                cs.Add(c)

            Next

            Dim a = cs.Where(Function(n As Control) (mode = SelectMode.Contains And rect.Contains(n.Bounds)) Or (mode = SelectMode.Intersects And rect.IntersectsWith(n.Bounds)))

            If shift Then editting = a.Union(selected) Else If alt Then editting = selected.Except(a) Else editting = a

            Invalidate()

        End If

    End Sub

    Protected Overrides Sub OnMouseUp(e As MouseEventArgs)

        MyBase.OnMouseUp(e)

        down = New Point(-1, -1)

        selected = editting.ToList()

        editting = Nothing

        Invalidate()

    End Sub

    Protected Overrides Function ProcessKeyPreview(ByRef m As Message) As Boolean

        Dim KeyCode As Keys = CInt(m.WParam) And CInt(Keys.KeyCode)

        Dim d As Boolean

        If m.Msg = H100 Or m.Msg = H104 Then d = True Else If m.Msg = H101 Or m.Msg = H105 Then d = False Else Return MyBase.ProcessKeyPreview(m)

        If KeyCode = Keys.ShiftKey Then

            shift = d

        ElseIf KeyCode = Keys.Menu Then

            alt = d

        End If

        Return MyBase.ProcessKeyPreview(m)

    End Function

    Protected Overrides Sub OnPaint(e As PaintEventArgs)

        MyBase.OnPaint(e)

        For Each c As Control In IIf(editting Is Nothing, selected, editting)

            e.Graphics.DrawRectangle(New Pen(Color.Gray) With {.DashStyle = Drawing2D.DashStyle.DashDot}, c.Left - 1, c.Top - 1, c.Width + 1, c.Height + 1)

        Next

        If (down.X  0) Then e.Graphics.DrawRectangle(New Pen(Color.Gray) With {.DashStyle = Drawing2D.DashStyle.DashDot}, rect)

    End Sub

End Class

Q2: VB.net GetWindowRect 问题

把这个函数改成这样就好vb.netrect了Declare Function GetWindowRect Lib "user32" Alias "GetWindowRect" (ByVal hwnd As Integer, ByRef lpRect As RECT) As Integer

Q3: vb.net，dim rects as rectangle（）（）=｛a，b，c，d，e，f｝ 我忘了双小括号的

Dim a As New System.Drawing.Rectangle(2，1，20,40)

Dim b As New System.Drawing.Rectangle(4，4，40,30)

Dim c As New System.Drawing.Rectangle(6，7，60,20)

Dim d  As New  System.Drawing.Rectangle(8，10,80,10)

Dim rectabcd = {a, b, c, d} ''数组(a、b、c、d)

Public Sub 调用组()

rectabcd.GetValue(2) ''获取rectabcd{c}返回值 Object。

……ListRect.Item(2).Height

rectabcd.ToList.Item(0)  ''获取或设置rectabcd.ToList[a]的值。

End Sub

Public ListRect As List(Of Drawing.Rectangle) = {New Rectangle(0, 0, 10, 10), New Rectangle(10, 1, 20, 20)}.ToList ''ListRect共2个Rectangle。

Q4: VB.NET想用GetWindowRECT获取某窗口的坐标，但测试结果是L,T,R,B显示都是0,0,0,0

很简单，原因有二。第一，VB里long是32位，但是VB.NET里是64位，Dim ksWND As Integer才对。第二，VB在API里默认传址，而VB.NET默认传值，所以API里要添加Private Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long,添加"ByRef" lpRect As RECT) As Integer

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Private Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long,byref lpRect As RECT) As Integer

Private Structure RECT

Dim Left As Integer

Dim Top As Integer

Dim Right As Integer

Dim Bottom As Integer

End Structure

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

Dim ksWND As integer

Dim ksTitle As String

Dim winS As RECT

If TextBox1.Text "" Then

ksTitle = TextBox1.Text

ksWND = FindWindow(vbNullString, ksTitle)

GetWindowRect(ksWND, winS)

MsgBox("左上角坐标(" winS.Left "," winS.Top ")" vbCrLf "右下角坐标(" winS.Right "," winS.Bottom ")" vbCrLf "窗口高" winS.Bottom - winS.Top "窗口宽" winS.Right - winS.Left)

Else

MsgBox("请填写窗口名称")

End If

End Sub

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