GetWindowText没有任何返回

Question

在我的一个项目中，我必须得到前台窗口的标题，所以我调用GetForegroundWindow（）入口点窗体User32.dll获取窗口句柄，然后我称为GetWindowText（）为标题一切都会出错少但输出什么也没有，这里是我在我的VB.NET程序中使用的代码。

Imports System.Runtime.InteropServices 

Public Class Form1 

<DllImport("user32.dll")> _ 
Private Shared Function GetForegroundWindow() As IntPtr 

End Function 

<DllImport("user32.dll")> _ 
Private Shared Function GetWindowText(ByVal hwnd As Long, ByVal lpString As System.Text.StringBuilder, ByVal cch As Long) As Integer 

End Function 


Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
End Sub 

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick 
    Dim hWnd As IntPtr 
    hWnd = GetForegroundWindow() 
    Dim title As New System.Text.StringBuilder(256) 
    GetWindowText(hWnd, title, title.Capacity) 
    Me.Text = title.ToString 
End Sub 
End Class 

Answer 1

我找到了自己的解决方案，这是为它必须是IntPtr程序的正常运作hWnd参数为Long值故障。新的正确代码看起来像这样。

Imports System.Runtime.InteropServices 

Public Class Form1 

<DllImport("user32.dll")> _ 
Private Shared Function GetForegroundWindow() As IntPtr 

End Function 

<DllImport("user32.dll")> _ 
Private Shared Function GetWindowText(ByVal hwnd As IntPtr, ByVal lpString As System.Text.StringBuilder, ByVal cch As Long) As Integer 

End Function 


Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
End Sub 

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick 
    Dim hWnd As IntPtr 
    hWnd = GetForegroundWindow() 
    Dim title As New System.Text.StringBuilder(256) 
    GetWindowText(hWnd, title, title.Capacity) 
    Me.Text = title.ToString 


End Sub 
End Class