平时使用VB编程时需要用到"打开文件"类似的对话框时我们一般需要添加一个commondialogue的控件。使用这个控件能完成如“打开”，“另存”，“颜色”，“打印”等众多的功能，但是如果一个功能很简单的程序，使用这个控件却也造成了一些不必要的麻烦。一个是需要安装，再个增加了发布文件包的体积。
下面介绍如何使用Window API显示一个“打开”的对话框：
General.bas:
Declare Function GetOpenFileName Lib "comdlg32.dll" Alias _
"GetOpenFileNameA" (pOpenfilename As OPENFILENAME) As Long

Type OPENFILENAME
lStructSize As Long
hwndOwner As Long
hInstance As Long
lpstrFilter As String
lpstrCustomFilter As String
nMaxCustFilter As Long
nFilterIndex As Long
lpstrFile As String
nMaxFile As Long
lpstrFileTitle As String
nMaxFileTitle As Long
lpstrInitialDir As String
lpstrTitle As String
flags As Long
nFileOffset As Integer
nFileExtension As Integer
lpstrDefExt As String
lCustData As Long
lpfnHook As Long
lpTemplateName As String

End Type
在调用对话框的按钮的click事件输入下面代码：
Private Sub FileOpen_Click()
Dim ofn As OPENFILENAME
Dim rtn As String
ofn.lStructSize = Len(ofn)
ofn.hwndOwner = Me.hWnd
ofn.hInstance = App.hInstance
ofn.lpstrFilter = "所有文件"
ofn.lpstrFile = Space(254)
ofn.nMaxFile = 255
ofn.lpstrFileTitle = Space(254)
ofn.nMaxFileTitle = 255
ofn.lpstrInitialDir = App.Path
ofn.lpstrTitle = "打开文件"
ofn.flags = 6148
rtn = GetOpenFileName(ofn)
If rtn >= 1 Then
msgbox ofn.lpstrFile
Else
msgbox "Cancel Was Pressed"
End If
End Sub