用SendMessage 模拟鼠标点击指定位置坐标出错

[lmhcs]

用SendMessage发送WM_LBUTTONDOWN，并在lparam指定坐标位置。但接受放接受到位置严重出错。不知道错误哪里。知道c#高手多，特来c#这边发帖，请教！贴代码

 Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
        '测试发送鼠标点击
        Dim res As Integer
        Win.SetForegroundWindow(hwnd) '窗体激活
        '测试鼠标窗体点击
        Dim x As Int16 = 58
        Dim y As Int16 = 155
        Dim pt As New Point(x, y)
        Dim lp As Int32 = Helper.ToLParam(x, y)
        lp = 10158138 '低16位58，高16位155
        MSG.SetCursorPos(x, y) '在网上看到SetCursorPos可以模拟点击制定位置，但本测试不行）
        res = MSG.SendMessage(hwnd, WM.WM_LBUTTONDOWN, MouseMK.MK_LBUTTON, lp)
        Threading.Thread.Sleep(200)
        res = MSG.SendMessage(hwnd, WM.WM_LBUTTONUP, MouseMK.MK_LBUTTON, lp)
    End Sub

上例发打算发送x=58，y=155坐标位置，但被模拟点击的程序收到的是：在 WndProc 方法lparam接受到是165864560，即x=58480，y=2530，这个坐标跟发送的坐标严重不一致。
api声明

Public Class MSG
    <DllImport("user32", SetLastError:=True)>
    Public Shared Function PostMessage(hWnd As IntPtr, Msg As UInteger, wParam As Integer, lParam As Integer) As Boolean
    End Function
    <DllImport("user32.dll", EntryPoint:="SendMessage", CharSet:=CharSet.Auto)>
    Public Shared Function SendMessage(hwnd As IntPtr, wMsg As Integer, wParam As Int32, ByRef lParam As Int32) As Int32
    End Function
    ''' <summary>
    ''' 成功返回非0
    ''' </summary>
    ''' <param name="x"></param>
    ''' <param name="y"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    <DllImport("user32.dll", EntryPoint:="SetCursorPos")>
    Public Shared Function SetCursorPos(x As Int32, y As Int32) As Int32
    End Function
End Class

'按键消息
Public Enum WM
    WM_LBUTTONDOWN = &H201
    WM_LBUTTONUP = &H202
    BM_CLICK = &HF5
End Enum

Public Enum MouseMK

    ''' <summary>
    ''' 鼠标左键
    ''' </summary>
    ''' <remarks></remarks>
    MK_LBUTTON = &H1
    ''' <summary>
    ''' 鼠标右键
    ''' </summary>
    ''' <remarks></remarks>
    MK_RBUTTON = &H2
    ''' <summary>
    ''' 鼠标中键
    ''' </summary>
    ''' <remarks></remarks>
    MK_MBUTTON = &H10 '

    MK_SHIFT = &H4
    ''' <summary>
    ''' 键盘Ctrl键
    ''' </summary>
    ''' <remarks></remarks>
    MK_CONTROL = &H8
End Enum



Public Class Helper
    ''' <summary>
    ''' y右移16位
    ''' </summary>
    ''' <param name="x"></param>
    ''' <param name="y"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function ToLParam(x As Int32, y As Int32) As Int32
        ' Return (y << 16) Or (x And &HFFFF)
        Return x + (y << 16)
    End Function

    ''' <summary>
    ''' 返回低16位
    ''' </summary>
    ''' <param name="lp"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function LoWord(lp As Int32) As Int16
        Dim mask As Int32 = &HFFFF
        Return (lp And mask)
    End Function
    ''' <summary>
    ''' 返回高16位
    ''' </summary>
    ''' <param name="lp"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function HiWord(lp As Int32) As Int16
        Dim mask As Int32 = &HFFFF
        Return (lp >> 16) And mask
    End Function

End Class

[lmhcs]

添加接受程序代码

    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        MyBase.WndProc(m)
        If m.Msg = WM_LBUTTONUP Then
            Console.WriteLine(m.LParam)
            Label1.Text = m.LParam
            Label2.Text = LoWord(m.LParam) & " " & HiWord(m.LParam)

        End If
    End Sub

[Jason_Mao1]

屏幕的坐标的分辨率 还有 DPI 有一定的关系，你多看看这方面的东西 。希望能帮助到你。

[秋的红果实]

 ''' y右移16位 Public Shared Function ToLParam(x As Int32, y As Int32) As Int32         ' Return (y << 16) Or (x And &HFFFF)         Return x + (y << 16)     End Function ==> 不知道你要将传递的数据变成什么形式？貌似将x坐标放到一个32位整数的高位部分，y放到低位部分 但是，看注解，y向右移，应该写：y>>16 调用函数时，lp = 10158138，这个值你是怎么来的？ 另外，输出sendMessage函数返回值是多少，验证是不是执行成功 另外可以尝试PostMessage函数，这个立刻返回。不过最后一个参数，也要定义为Byref的

[秋的红果实]

在 WndProc 方法lparam接受到是165864560，即x=58480，y=2530 ==> 这个转换是怎么进行的？ 发送的x，y编码成一个数lp，接收到后，再还原为坐标，规则必须是一样的 平时用win32 API的毕竟少，只能帮到这里了

[lmhcs]

to From_TaiWan 朋友： WM_LBUTTONDOWN消息，wparam参数是指示鼠标按键参数，lparam是坐标信息。其中x坐标为lp的低16位，高16位为y坐标 Public Shared Function ToLParam(x As Int32, y As Int32) As Int32 ' Return (y << 16) Or (x And &HFFFF) Return x + (y << 16) End Function 这个函数应该没有错吧？！我把x坐标放在低16位，y坐标左移16位后。即高十六位啊。 我在网上百度很久，网上差不多都用这种方法。但我测试就不能发送成功，不知道是不是 64位系统的缘故。我是win7 64位。 至于10158138，是我拦截消息是的鼠标坐标值， Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message) MyBase.WndProc(m) If m.Msg = WM_LBUTTONUP Then Console.WriteLine(m.LParam) Label1.Text = m.LParam Label2.Text = LoWord(m.LParam) & " " & HiWord(m.LParam) End If End Sub 当lp=10158138，x坐标就是58，y坐标就是155。

[xuzuning]

鼠标位置是相对控件左上角的，你考虑到这点了吗？

[真相重于对错]

The WM_LBUTTONDOWN message is posted when the user presses the left mouse button while the cursor is in the client area of a window. If the mouse is not captured, the message is posted to the window beneath the cursor. Otherwise, the message is posted to the window that has captured the mouse.

[zzyhost]

推荐你用SendInput，很好很强大

[lmhcs]

结帖。上面的错误是sendmessage声明错误。郁闷死。一直没有发现。。。。 在vb中正确声明， <DllImport("user32.dll", EntryPoint:="SendMessage", CharSet:=CharSet.Unicode)> Public Shared Function SendMessage(hwnd As IntPtr, wMsg As Integer, wParam As IntPtr, ByVal lParam As IntPtr) As Int32 End Function

[srgcc]

遇到同样的问题，楼主知道为什么CharSet:=CharSet.Unicode这样就可以吗？ 是不是64位的系统就需要这样声明？