Question

Some quick questions:

So I have this LogInWindow dialog that I use to collect all the SQL login info and then pass the constructed connection string to the ServiceManager.InitializeContext() method, which initializes my entities context with a specific provider connection.

It’s all working fine. But I would like to initialize the LogInWindow dialog with the values that are defined in the App.config configuration file.

Is there a preferred method for doing this initial setup? i.e., should I resort to instantiating a dummy EntityContext using the default constructor just for the sheer purpose of fetching the default provider connection? Is there a “cleaner” way?

By the way, would you consider it a “safe” practice to do this type of Form.Close() invocation inside a handler to the Form.Shown event? I read on MSDN that it is not advisable to call Form.Close() inside a handler to the Form.Load event.

public partial class MainWindow : Form {

    private void MainWindow_Shown(object sender, EventArgs e) {
        using (var logInWindow = new LogInWindow()) {
            if (logInWindow.ShowDialog(this) == DialogResult.OK) {
                this.serviceManager.InitializeContext(logInWindow.ConnectionString);
            } else {
                this.Close();
            }
        }
    }
}


public sealed class ServiceManager : IDisposable {

    public void InitializeContext(string connectionString) {
        if (this.EntityContext != null)
            throw new InvalidOperationException("EntityContext cannot be initialized multiple times.");

        var entityConnectionString = new EntityConnectionStringBuilder();
        entityConnectionString.ProviderConnectionString = connectionString;
        entityConnectionString.Provider = "System.Data.SqlClient";
        entityConnectionString.Metadata = "res://*/EntityModel.EntityModel.csdl|res://*/EntityModel.EntityModel.ssdl|res://*/EntityModel.EntityModel.msl";

        this.EntityContext = new EntityContext(entityConnectionString.ConnectionString);
        this.EntityContext.ObjectMaterialized += EntityContext_ObjectMaterialized;
    }
}

Answer 1

You can access all parts of your App.config using System.Configuration class

Example:

var connectString = ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;

var stringBuilder = new SqlConnectionStringBuilder(connectString);

string UserID = stringBuilder.UserID;
string Password = stringBuilder.Password;
string catalog = stringBuilder.InitialCatalog;

App.config

<configuration>
   <connectionStrings>
     <add name="MyConnectionString" connectionString="metadata=res://*/...........
   </connectionStrings>
</configuration>