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VB如何使你的程序同文件扩展名建立关联?

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VB如何使你的程序同文件扩展名建立关联?



如果你的程序是同文件操作有关,比如说你自定义了一个文件类型,用你的程序才能打开它并查看其中的内容。你有没有想过在你的文件同你的程序之间建立关联,这样不必每次都要先启动程序,再打开文件了。用户可直接点选你的文件,而不必每次都要面对一个“打开方式”对话框。其实要做到这一点,只须调用API函数就行了。下面的代码向你演示如何实现这一功能。


首先在窗体的通用声明段中加入下面的代码:


Option Explicit

Private Declare Function RegCreateKey Lib "advapi32.dll" Alias "RegCreateKeyA" (ByVal hKey As Long, _
ByVal lpSubKey As String, phkResult As Long) As Long
Private Declare Function RegSetValue Lib "advapi32.dll" Alias "RegSetValueA" (ByVal hKey As Long, _
ByVal lpSubKey As String, ByVal dwType As Long, ByVal lpData As String, ByVal cbData As Long) As Long

' Return codes from Registration functions.
Const ERROR_SUCCESS = 0&
Const ERROR_BADDB = 1&
Const ERROR_BADKEY = 2&
Const ERROR_CANTOPEN = 3&
Const ERROR_CANTREAD = 4&
Const ERROR_CANTWRITE = 5&
Const ERROR_OUTOFMEMORY = 6&
Const ERROR_INVALID_PARAMETER = 7&
Const ERROR_ACCESS_DENIED = 8&

Private Const HKEY_CLASSES_ROOT = &H80000000
Private Const MAX_PATH = 260&
Private Const REG_SZ = 1

在窗体的Click事件中加入下面的代码
Private Sub Form_Click()

Dim sKeyName As String 'Holds Key Name in registry.
Dim sKeyValue As String 'Holds Key Value in registry.
Dim ret& 'Holds error status if any from API calls.
Dim lphKey& 'Holds created key handle from RegCreateKey.

'This creates a Root entry called "MyApp".
sKeyName = "MyApp"
sKeyValue = "My Application"
ret& = RegCreateKey&(HKEY_CLASSES_ROOT, sKeyName, lphKey&)
ret& = RegSetValue&(lphKey&, "", REG_SZ, sKeyValue, 0&)

'This creates a Root entry called .BAR associated with "MyApp".
sKeyName = ".BAR"
sKeyValue = "MyApp"
ret& = RegCreateKey&(HKEY_CLASSES_ROOT, sKeyName, lphKey&)
ret& = RegSetValue&(lphKey&, "", REG_SZ, sKeyValue, 0&)

'This sets the command line for "MyApp".
sKeyName = "MyApp"
sKeyValue = "c:\mydir\my.exe %1"
ret& = RegCreateKey&(HKEY_CLASSES_ROOT, sKeyName, lphKey&)
ret& = RegSetValue&(lphKey&, "shell\open\command", REG_SZ, _
sKeyValue, MAX_PATH)
End Sub
按F5运行程序并在窗体上点击一下鼠标,然后退出程序.


从开始菜单中运行REGEDIT,你可在HKEY_CLASSES_ROOT下找到.bar和MyApp两个子项,结构如下所示:

.bar = MyApp
MyApp = My Application
|
-- Shell
|
-- open
|
-- command = c:\mydir\my.exe %1


你可以查看关于RegCreateKey和RegSetValue的用法说明。

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