var cn = new SqlConnection();
cn.ConnectionString = @"Data Source=.;AttachDbFilename=C:\Users\Yoshimi\Documents\Visual Studio 2010\WebSites\WebSite1\App_Data\Database.mdf;Integrated Security=True;User Instance=True";
cn.Open();
var Ucheck = new SqlCommand();
Ucheck.Connection = cn;
Ucheck.CommandText = "SELECT username FROM member WHERE(username = '" +TextBoxUsername.Text+ "')";
var dr = Ucheck.ExecuteReader();