WPF, What's the best way to store a constant to be used at startup?

Question

I have a WPF application that accesses a database instance. I develop on my personal machine and the application will run on another machine and database instance. Is there a way or best practice for storing the instance name outside of the WPF application that I can read upon app startup? Currently I have comment and uncomment the database instance name as I move from machine to machine. I would like to have something stored on the local machine that I can just read when the application is launched.

Here is what I currently do:

try
        {
            if (sqlConn != null)
            {
                sqlConn.Close();
            }

            strConnection = "Data Source=" + strDBInstance + "; Initial Catalog=NBFoodPantry;Integrated Security=true; MultipleActiveResultSets = True";
            //strConnection = "Data Source=CASS-LAPTOP\\SQLEXPRESS; Initial Catalog=NBFoodPantry;Integrated Security=true; MultipleActiveResultSets = True";
            //strConnection = "Data Source=KENTS-WORK-PC\\CASS_SQLEXPRESS; Initial Catalog=NBFoodPantry;Integrated Security=true; MultipleActiveResultSets = True";

            sqlConn = new SqlConnection(@strConnection);
            try
            {
                sqlConn.Open();
            }
            catch (Exception ex)
            {
                string strMsg;

                WriteErrorLog(strErrorLogFile, "ConnectToDatabase", ex.Message, false);
                strMsg = "ConnectToDatabase: SQL Open failed.  Please make sure that you database ";
                strMsg += "instance and name are correct.  Also make sure that the SQL engine is running.";
                System.Windows.MessageBox.Show(strMsg);
            }
        }
        catch (Exception ex)
        {
            string strMsg;

            WriteErrorLog(strErrorLogFile, "ConnectToDatabase", ex.Message, false);
            strMsg = " ConnectToDatabase: failed with error, " + ex.Message + ".";
            System.Windows.MessageBox.Show(strMsg);
        }

Answer 1

This is what application settings are designed to handle. Under the properties node in your project, open the settings. This has built in support for connection strings:

Then you can access the settings in your code by its name:

Properties.Settings.Default.ConnectionString

All of this is stored in your App.config, which you can modify on various machines to have different values.