连接SQL数据库时出现错误

结果如下:

PatientDatabase.Properties。"设置"不包含"SQL"的定义，也没有扩展方法"SQL"接受类型为"PatientDatabase.Properties"的第一个参数。"可以找到Settings"(您是否缺少using指令或程序集引用?)

下面是我的代码:

private void Form1_Load(object sender, EventArgs e)
{
        try
        {
            objConnect = new DatabaseConnection();
            conString = Properties.Settings.Default.patientDetailsConnectionString;
            objConnect.connection_string = conString;
            objConnect.sql = Properties.Settings.Default.SQL;
            ds = objConnect.GetConnection;
            MaxRows = ds.Tables[0].Rows.Count;
            NavigateRecords();
        }
        catch (Exception err)
        {
            MessageBox.Show(err.Message);
        }
}