How to login from webservices

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C#

My scenario is that i want to get record from database against SQL Query SELECT * from RegisterUsers WHERE Email ='" + Email +'".
Actually we are making and android application and Web Application, when a user login via Android application the Query pass via web services and get details from SQL Server Database.
here is my code but it gives me error, and help me please i have wasted 2 days and searched too much on web services.

private bool Profile(string Email, string password)
{
    SqlConnection NewCon;
    NewCon = Class1.GetConnection();
    string cmdString = ("SELECT * FROM RegisterUsers WHERE Email = @Email AND Password = @pw");

    SqlCommand cmd = new SqlCommand(cmdString, NewCon);

    cmd.Parameters.Add("uname", SqlDbType.VarChar).Value = Email;
    cmd.Parameters.Add("pw", SqlDbType.VarChar).Value = password;

    DataSet loginCredentials = new DataSet();
    SqlDataAdapter dataAdapter;
    if (NewCon.State.Equals(ConnectionState.Closed))
    {
        NewCon.Open();

        dataAdapter = new SqlDataAdapter(cmd);
        dataAdapter.Fill(loginCredentials);

        NewCon.Close();

        if (loginCredentials != null)
        {
            if (loginCredentials.Tables[0].Rows.Count > 0)
            {
                return true;
            }
        }
    }
    return false;
}