Cant get users password from database

[Twistar]

Hi, i need to get a users password from my database. I ask the user to enter his username in my textbox called txtUsername and his password in txtPassword. Then I try to use LinQ to sql to get the password.
My Code:

public string GetPasswordHash()
        {
            var varPasswordHash = (from m in dataContext.Members
                                   where m.username == txtUsername.Text
                                   select m.password);
            string passwordHash = Convert.ToString(varPasswordHash);
            lblBasehash.Text = passwordHash;

            return passwordHash;
        }

But this method only returns this:
SELECT [t0].[password] FROM [dbo].[Members] AS [t0] WHERE [t0].[username] = @p0