IndexOutOfRangeException的问题

SqlConnection RegCon = new SqlConnection(ConfigurationManager.AppSettings["SQLConn"]);
        RegCon.Open();
        SqlCommand checkname = new SqlCommand("select count (*) from UserInfo where Name='" + this.LoginIDEnter.Text + "' and  PW='" + this.LoginPWEnter.Text + "'",RegCon);
        SqlDataReader checkid = checkname.ExecuteReader();
        
        if (checkid.Read())
        {
            userid = checkid["Name"].ToString();
        }

在userid = checkid["Name"].ToString()这里报错，请问是错在哪里？谢谢。