How to add connection string in Config File in WPF Application

Question

I am a beginner and learning WPF Application. I have a simple project and in that I want to read DB Configuration string from App.Config File. But I am not able to do so. Below is my attempt:

APP.Config File:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
    </startup>
  <connectionStrings>
    <add name="DBCS" connectionString="Data Source=.\;Initial Catalog=Connect;Integrated Security=SSPI" providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

CS Code:

    public static void GetDataFromDB()
            {
                //var CS = @"Data Source=.\;Initial Catalog=Connect;Integrated Security=SSPI";
               // ABOVE CODE WORKS FINE
                string CS = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
                using (SqlConnection con = new SqlConnection(CS))
                {
                    con.Open();
                    SqlDataAdapter da = new SqlDataAdapter("Select * from tblTenant", con);
                    DataSet ds = new DataSet();
                    da.Fill(ds);
                }
            } 

Edit:

Answer 1

You need to put the connnection string in the App.config of the running WPF application and not in the DAL or any other class library.

The ConfigurationManager class reads the configuration file of the running executable.