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Old April 8th, 2004, 04:39 PM
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Default Variable Path in web.Config Connection String?

I am accustomed to using Server.MapPath in connection strings as below
     objConn.Open "Driver={Microsoft Access Driver (*.mdb)};" &_
             "DBQ=" & Server.MapPath("DB\Volume.mdb")

Now in .NET applications, I am able to use the web.config file, to provide a global connection string:
      <add key = "JBulletin"
           value = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=c:\Bulletin\DB\Volume.mdb;" />

However, is there any way to leave the path 'variable' in the web.config file, as with the MapPath method of the Server object (realizing of course that the web.config is XML and not asp script)


Old April 9th, 2004, 01:50 PM
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You can retrieve a connection string in your app as:

objConn.Open(ConfigurationSettings.AppSettings("Co nnString") & Server.MapPath("DataSource"))

You can't trigger a server.mappath in appsettings, but you can store the path as a separate variable.
Old April 9th, 2004, 05:23 PM
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Here's a clever solution that seems to work...

In your config file you store the path like this:

     Data Source={0}\DB\Volume.mdb

Then where you use the path in code, you map the root of the virtual directory and use that as the source of the replacement in String.Format:

String.Format(sPath, Server.MapPath("~"))

The ~ represents the virtual directory path. You can use this to establish a "root" reference to a resource. I.e. if you try to reference something with "/myResource" and you are running in virtual directory path "myWebApp" the resource url will reference "myServer/myResource" instead of the correct "myServer/myWebApp/myResource". ASP.net automatically fills in the ~.

So now, regardless of where the virtual directory lives on the physical machine, the {0} in the path will get replaced with the virtual directory's physical path.

Work smarter, not harder
Old April 12th, 2004, 04:58 PM
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Thanks for the help. The solution I am employing is a simplistic version of those you both provided. Essentially, I am storing the database name in one variable (or "key") in web.config and then the sub-folder tree structure in a second web.config key (could as easily store them as one, but I like the separation).

This leaves the ability to change both the folder and database name centrally. In the code-behind, I use MapPath and concatenate the subfolder structure then the filename, and acheive the separability and independence betweem code and filename/folder maintenance I was looking for.

Thank you very much for the prompt and helpful replies.


Old June 21st, 2004, 05:44 PM
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Could you please post the code that you ended up using? I'd like to see the solution. Thanks.

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