How to rewrite Webconfig connection string at runtime

Question

How to rewrite Webconfig connection string at runtime.I have input textbox for Server,UserName and Password.Is it Possible to read from these textbox?

Answer 1

It depends how you are creating your connection but sure it is possible.

Have a look at this site for the connection string particular to the db you are connecting to..

ConnectionStrings.com

For a SQL connection string you'd do something like

 Imports System.Data.SqlClient
 ...
 ...
 Dim conn As SqlConnection = New SqlConnection("Data Source=myServerAddress;Initial  Catalog=myDataBase;User Id=myUsername;Password=myPassword;")
 conn.Open

Replace the bits you want to change with the values from your text box

e.g

 Dim conn As SqlConnection = New SqlConnection("Data Source=" & txtServerAddr.Text & ";Initial  Catalog=" & txtDBName.Text & ";User Id=" & txtUser.Text & ";Password=" & txtPassword.Text & ";")

EDIT following edit to your question

Ahh makes more sense now.

OK, you have two alternatives now. If you have a limited number of connection strings that you are connecting to (maybe Live, Test, Live#2) it would make more sense to add additional connection strings into your web.config and then offer them as a drop down as you enter your web app.

You can read more on how to pull named connection strings out of web.config here.. Microsoft How to: Read Connection Strings from the Web.config File

If you have an unlimited number of possible connection strings then I would avoid web.config completely and build your connection string on the fly as in my original answer

ADDITION

"It's not a good idea to edit web.config at runtime. Realize that any change you make to web.config will result in the application being restarted on your webserver."