It is very common that you come across scenario when at run time you need to change the database server and so the connection string is used in your LINQ. This may come as requirement, if you are moving your application from dev server to staging and from staging to production.

There are two ways you can change connection string on fly

  1. Edit config file
  2. Build connection string to pass as constructor of DataContext.

Edit config file

You can do it in two ways. Open the configuration file and edit connection string here.


In other way, you can change connection string is open DBML file and right click then select Properties


In properties tab create on Connection and click on Connection String


In connection properties dialog box you can change the connection so the connection string.


Editing Connection String in code

Assuming you is creating a function to return connection string. Crete function that it takes server name as input parameter. Your function should be like below.


You can pass server name to this function to create connection string and use output of this function in constructor of DataContext


So here you can pass any server name to create DataContext as of server.

For reference code is as below ,

 static string GetConnectionString(string serverName)

            System.Data.SqlClient.SqlConnectionStringBuilder builder =
                           new System.Data.SqlClient.SqlConnectionStringBuilder();
            builder["Data Source"] = serverName;
            builder["integrated Security"] = true;
            builder["Initial Catalog"] = "Sample2";
            return builder.ConnectionString;


I hope this post was useful. Thanks for reading.  Smile

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