GetWindowText沒有任何返回

Question

在我的一個項目中，我必須得到前臺窗口的標題，所以我調用GetForegroundWindow（）入口點窗體User32.dll獲取窗口句柄，然後我稱爲GetWindowText（）爲標題一切都會出錯少但輸出什麼也沒有，這裏是我在我的VB.NET程序中使用的代碼。

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

我找到了自己的解決方案，這是爲它必須是IntPtr程序的正常運作hWnd參數爲Long值故障。新的正確代碼看起來像這樣。

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