API SendMessage（）不適用於外部應用程序對話框

Question

我創建了一個具有2個按鈕的窗體。一個按鈕彈出一個msgbox，另一個按照下面列出的frmAPI（代碼如下）運行。如果我打開msgbox並將其保持打開狀態，然後運行frmAPI，它將列出msgbox及其文本，然後關閉它。這是我期望它做的。如果我打開另一個應用程序並在該應用程序中生成msgbox，並且我的frmAPI仍在運行，它實際上會列出其他應用程序msgbox和文本，但它不會從另一個應用程序關閉msgbox。如果Irun來自其他應用程序的frmAPI並執行相同的測試，則結果會相反。簡而言之，它只會關閉同一個應用程序中的對話框。

我希望能夠從任何應用程序關閉對話框，基於它是一個對話框，並具有符合我的標準的文本。任何幫助我做錯了什麼？

感謝

Imports System.Runtime.InteropServices 
Imports System.Text 

Partial Public Class TestMSgBoxStuff 
    Inherits Form 
    Public Sub New() 
     InitializeComponent() 
    End Sub 

    <DllImport("user32.dll", SetLastError:=True)> _ 
    Private Shared Function FindWindow(lpClassName As String, lpWindowName As String) As IntPtr 
    End Function 

    <DllImport("user32.dll", SetLastError:=True)> _ 
    Private Shared Function FindWindowEx(hwndParent As IntPtr, hwndChildAfter As IntPtr, lpszClass As String, lpszWindow As String) As IntPtr 
    End Function 

    <DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _ 
    Private Shared Function GetWindowText(hWnd As IntPtr, lpString As StringBuilder, nMaxCount As Integer) As Integer 
    End Function 

    <DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _ 
    Private Shared Function GetWindowTextLength(hWnd As IntPtr) As Integer 
    End Function 

    <DllImport("user32.dll", SetLastError:=True)> _ 
    Private Shared Function SendMessage(hWnd As HandleRef, Msg As UInteger, wParam As IntPtr, lParam As IntPtr) As IntPtr 
    End Function 
    <DllImport("user32", CharSet:=Runtime.InteropServices.CharSet.Auto, SetLastError:=True, ExactSpelling:=True)> 
    Private Shared Function SetForegroundWindow(ByVal hwnd As IntPtr) As IntPtr 
    End Function 


    Private Const WM_IME_NOTIFY As Integer = &H282 
    Private Const WM_DESTROY As Integer = &H2 
    Private Const WM_NCDESTROY As Integer = &H82 
    Private Const WM_CLOSE As Integer = &H10 
    Private Const IMN_CLOSESTATUSWINDOW As Integer = &H1 
    Private Const WM_KILLFOCUS As Integer = &H8 
    Private Const WM_COMMAND As Integer = &H11 



    Private Sub TestMSgBoxStuff_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load 
     Dim timer As New Timer() 
     Timer1.Interval = 10000 
     'detect the MessageBox every seconds 
     'Timer1.Tick += New EventHandler(Timer1_Tick) 
     Timer1.Start() 
    End Sub 

    Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick 
     'Get the MessageBox handle 
     Dim handle As IntPtr = FindWindow("#32770", Nothing) 
     Me.RichTextBox1.AppendText("Handle: " + handle.ToString() + vbLf) 

     'Get the Text window handle 
     Dim txtHandle As IntPtr = FindWindowEx(handle, IntPtr.Zero, "Static", Nothing) 
     Me.RichTextBox1.AppendText(vbTab & "text handle: " + txtHandle.ToString() + vbLf) 
     Dim len As Integer = GetWindowTextLength(txtHandle) 
     Dim sb As New StringBuilder() 

     'Get the text 
     GetWindowText(txtHandle, sb, len + 1) 
     Me.RichTextBox1.AppendText(vbTab & "text: " + sb.ToString() + vbLf & vbLf) 
     Me.RichTextBox1.ScrollToCaret() 

     SetForegroundWindow(handle) 

     'close the messagebox WM_CLOSE 
     Dim lResults As Integer = SendMessage(New HandleRef(Nothing, handle), WM_NCDESTROY, IntPtr.Zero, IntPtr.Zero) 

    End Sub 
End Class 

Answer 1

您可能正在運行到User Interface Privilege Isolation。這會阻止您的消息進入更高的權限流程。另請參見ChangeWindowsMessageFilter()

我建議嘗試發送一個WM_COMMAND而不是WM_CLOSE;系統通常會更輕鬆地對待WM_COMMAND，並且可能會通過。使用BN_CLICKED作爲WPARAM和IDOK的高位字作爲低位字（假設它具有OK按鈕）以及LPARAM中的OK按鈕的句柄。其他按鈕消息是here。