要關閉其他程式，有些網友會以為用DestroyWindow這API函數，但是這個函數只限於關閉自己程式的視窗，因此我要要用SendMessage，以下是範例：
請先準備Text1，Command1各一個，再輸入：
Option Explicit
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Const WM_CLOSE = &H10
Private Sub Command1_Click()
Dim MhWnd As Long
MhWnd = FindWindow(vbNullString, Text1.Text)
If MhWnd = 0 Then
MsgBox "找不到視窗!"
Exit Sub
End If
SendMessage MhWnd, WM_CLOSE, ByVal 0&, ByVal 0&
End Sub
範例的用法是：
首先在Text1輸入某視窗的標題，然後按Command1，那麼那個視窗就會被關閉了！