如何使用关联程序打开一个文件？
比如一个叫aaa.dat的文件，WINDOWS默认是打不开的，你双击会弹出一个框，问你用什么程序打开，这个如何用程序做？

简单的说，如何对一个文件调用“打开方式”对话框？

[解决办法]
ShellExecute 0, vbNullString, "rundll32.exe ", "shell32.dll,OpenAs_RunDLL ", "c:\a.bmp\ ", 10

[解决办法]
sorry 参数写错了
ShellExecute 0, vbNullString, "rundll32.exe ", "shell32.dll,OpenAs_RunDLL c:\a.bmp ", " ", 10

[解决办法]
Declare Function ShellExecuteA Lib "shell32.dll " (ByVal hWnd As Long, _
ByVal lpOperation As String, _
ByVal lpFile As String, _
ByVal lpParameters As String, _
ByVal lpDirectory As String, _
ByVal nShowCmd As Long) As Long
Function ShellDoc(strFile As String)
Const SE_ERR_NOASSOC = 31
Dim lngRet As Long
lngRet = ShellExecuteA(0&, "open ", strFile, vbNullString, vbNullString, vbNormalFocus)
If lngRet = SE_ERR_NOASSOC Then
'示打方式窗口
Call ShellExecuteA(0&, vbNullString, "RUNDLL32.EXE ", "shell32.dll,OpenAs_RunDLL " _
& strFile, vbNullString, vbNormalFocus)
End If
End Function