Connection String issues in WPF - sql-server

Question

I have just completed my first project in WPF using C# and MS SQL 2008 express. I have used Visual Studio 2010. What I have right now is a class `conn.cs' that has a method that returns me the connection string as and when I require. Also I just noticed that I have an App.Config file that also has a connection string defined there (both strings refer to the same database).
My conn.cs
class conn
{
public string get_connection()
{
string conn_string = #"Data Source=.\sqlexpress;Initial Catalog=msp;Integrated Security=True;Pooling=False";
return conn_string;
}
}
App.Config
<connectionStrings>
<add name="msp.Properties.Settings.mspConnectionString" connectionString="Data Source=.\sqlexpress;Initial Catalog=msp;Integrated Security=True;Pooling=False" providerName="System.Data.SqlClient"/>
</connectionStrings>
I want to know two things now.
How can I fetch the Connection String from the App.Config? I need to do this then, I will fetch the string in my conn.cs from there, and then, I will just change the connection string in the app.config as and when required.
Also tell me, is it possible to set connection string at run time? I want the user to browse to the database (.mdf) file on First Run and then the connection string should get generated and saved in app.config. I can then easily pick it up from there and use.
Please provide suggestions.

Answer 1

You should be able to get access your connection string using this:
string connString = Properties.Settings.Default.mspConnectionString;
(when typing Properties.Settings.Default you should automatically see your choices in the Member List)
You can of course set the connection string at runtime; it is basically just another string. I would not recommend hard-coding the connection string; though.
You might want to give the SqlConnectionStringBuilder class a try; see this MSDN article for example. But actually I never used it so far except for a few experiments here and there although I literally only do database-driven software...