Login window on a dll C# project

I'm developing a DLL project that make transactions with a database server, the only problem is that must be an idependent DLL, and it needs to ask for a login screen if not found any previous information. This login screen needs to be written in C#, just lik开发者_如何学Goe an Windows Application.

Any ideas would be very apreciatted.

Thanks in advance

This isn't the sort of thing you would typically put into a dll. A login screen would be dependent on the implementing UI. You would be better of creating a data access class that implements an interface that has the login credentials required implemented as properties. This allows any consuming application (web, winforms, wpf, whatever) to create a login screen or pass direct credentials to the data class:

public interface IMyDataInterface
{
    string loginUser { get; set; }
    string loginPW { get; set; }
}

public class MyDataLayer : IMyDataInterface
{
    public MyDataLayer(string login, string pw)
    {
        loginUser = login;
        loginPW = pw;
    }
}

Using the interface faithfully guarantees that any exposed datalayer has the same implementation basics for consuming applications.

Edit to reflect more secure method: (idea by @Chris)

using System.Net;

public interface IMyDataInterface
{
    NetworkCredential credentials { get; set; }
}

public class MyDataLayer : IMyDataInterface
{
    public MyDataLayer(NetworkCredential loginInfo)
    {
        credentials = loginInfo;
    }
}

The constructor can be overloaded to include multiple methods of providing the credentials, but the SecureString class should be used to contain the password in all calls.