title: Modifying connection string with variables
body: <p>so my goal is to have a "settings form" which allows users to edit the connection string (by changing the database name / server location.</p>
  
  <p>The reason for this is that it it needs to be able to changed when the server locations changes shortly by someone who may not have any C# experience (Front-End GUI).</p>
  
  <p>I've created the connection strings in app.config but cannot find a way to assign variables inside the conn string that can be changed? I've created some application wide settings using the project properties. This is my app.config</p>
  
  <pre><code>&lt;connectionStrings&gt;
      &lt;add name="xxxx"
          connectionString="Data Source=ServerIP;Initial Catalog=DBName;Persist Security Info=True;User ID=user;Password=password"
          providerName="System.Data.SqlClient" /&gt;
  &lt;/connectionStrings&gt;
  &lt;applicationSettings&gt;
      &lt;xxx.Properties.Settings&gt;
          &lt;setting name="ServerIP" serializeAs="String"&gt;
              &lt;value /&gt;
          &lt;/setting&gt;
          &lt;setting name="DBName" serializeAs="String"&gt;
              &lt;value /&gt;
          &lt;/setting&gt;
      &lt;/xxx.Properties.Settings&gt;
  &lt;/applicationSettings&gt;
  </code></pre>