Question

vb.net中SendMessager的问题

Public Class Form1
Private Declare Auto Function FindWindow Lib "user32" (ByVal lpClassName As String, ByVal lpWindowName As String) As Integer
Private Declare Function FindWindowEx Lib "user32.dll" Alias "FindWindowExA" (ByVal hWnd1 As Int32, ByVal hWnd2 As Int32, ByVal lpsz1 As String, ByVal lpsz2 As String) As Int32
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As String, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As String) As Long
Private Const WM_SETTEXT = &HC
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Call GetWindowTitle()
End Sub
Private Sub GetWindowTitle()
Dim hWnd As Integer
Dim RichEdit As String
hWnd = FindWindow("Notepad", "无标题 - 记事本")
MsgBox(hWnd)
RichEdit = FindWindowEx(hWnd, 0, "Edit", vbNullString)
MsgBox(RichEdit)
SendMessage(RichEdit, WM_SETTEXT, 0, "hhhhhhhh")
End Sub
End Class

这个程序中最后的那个SendMessage老是出错，不知道什么问题呀，本人初学，那个SendMessage中的参数怎么定义的呀，我网上找了半天也没一个看的懂的说

Answer 1

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As String, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As String) As Long

改为

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As String, ByVal wMsg As integer, ByVal wParam As integer , ByVal lParam As String) As integer

再试试，
可能你的声明使用vb6。0 复制过来的，long 全部改成integer

Answer 2

很不正常！
VB6自带了这个函数，为什么要去申明API！
这个函数的用法：
SendMessage 要发送的字符串