Fetching EntityConnection string from app configuration file

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;
    }
}

sa_ddam213 · Accepted Answer · 2012-11-29 01:48:07Z

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>

edited Nov 29, 2012 at 1:48

answered Nov 29, 2012 at 0:36

sa_ddam213

43.7k7 gold badges105 silver badges112 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Fernando Espinosa Over a year ago

Thanks. Now I'm curious, what type of connection does the ConfigurationManager.ConnectionStrings collection return? A EntityConnection? Keep in mind I'm only interested in the provider connection string part of it.

Fernando Espinosa Over a year ago

Oh, I see, it's a ConnectionStringSettings... Problem is, that type does not break the connection string into parts, i.e., the Initial Catalog, Uset ID, Password, etc... I still find using the ConfigurationManager useful though.

sa_ddam213 Over a year ago

I have an application that does exactly what you are tying to do, I just split the connection string to get the Username/password. There could be a nicer way to do this, but I have found no problems with the hacky way I am doing it :)

sa_ddam213 Over a year ago

There is a way to do what you want, fixes my implementation too :) Updated above

STLDev Over a year ago

I realize that this is an old answer, but thought it would be helpful for others to know that I've found it not to work with current versions of ADO.Net. When I call the SqlConnectionStringBuilder() constructor, it fails with an exception with the message "Keyword not supported: 'metadata'." My connection string is a standard EF connection string - ` <connectionStrings><add name="Development" connectionString="metadata=res://*/BModel.csdl|res://*/BModel.msl;provider=System.Data.SqlClient;provider connection string='data s...." providerName="System.Data.EntityClient"/></connectionStrings>`

Collectives™ on Stack Overflow

Fetching EntityConnection string from app configuration file

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related