JData 使用教程 对输入数据进行验证（服务端验证）

JData 使用教程（五） 对输入数据进行验证（服务端验证）

JData 除了可以在客户端验证数据，还可以在服务端对数据进行验证。如下图所示：

服务端代码如下：

        [WebMethod]
        public ExecuteResult UpdateOrderWithValidate(Dictionary<string, object> item)
        {

            string freightError = null;
            string shipNameError = null;

            var Freight = Convert.ToInt32(item["Freight"]);
            var ShipName = Convert.ToString(item["ShipName"]);

            //Validate the values.
            if (Freight > 2)
                freightError = "Please enter a value less than or equal to 2.";

            if (ShipName == null || ShipName.Length > 5)
                shipNameError = "Please enter no more than 5 characters.";

            if (freightError != null || shipNameError != null)
            {
                var message= new { Freight = freightError, ShipName = shipNameError };
                return new ExecuteResult { AffectedRowCount = 0, Message = message};
            }

            //Update the data
            return new ExecuteResult { AffectedRowCount = 1 };
        }

上面那段代码，首先是对数据进行验证，然后创建一个包含错误信息的匿名对象，并将请对象赋值给 ExecuteResult 的 Message 成员，以便将错误信息返回到客户端，而 AffectedRowCount = 0 表示更新失败。该匿名对象的成员名称必须与验证对象的属性对应。 

也就是下面这条语句。

  var message = new { Freight = freightError, ShipName = shipNameError };
　return new ExecuteResult { AffectedRowCount = 0, Message = message };

客户端的脚本如下：

        Sys.onReady(function() {

            var o = new WebApplication.OrderMetaType();
            var dataSource = new JData.WebServiceDataSource("../Services/NorthwindService.asmx", "GetOrders", null, "UpdateOrderWithValidate");
            dataSource.set_selector([o.OrderID, String.format('{0} + " " + {1} as EmployeeName', o.Employee.FirstName, o.Employee.LastName), o.Freight, o.ShipName]);
            var col1 = new JData.BoundField(o.OrderID, null, '80px', null, true);
            var col2 = new JData.BoundField('EmployeeName', null, '120px', '112px', true);
            var col3 = new JData.BoundField(o.Freight, null, '80px', '72px');
            var col4 = new JData.BoundField(o.ShipName, null, '220px');

            var col5 = new JData.CommandField();
            col5.set_showEditButton(true);
            col5.set_showCancleButton(true);
            col5.get_itemStyle().set_width('90px');

            var gridView = new JData.GridView($get('gridView'));
            gridView.set_dataSource(dataSource);
            gridView.set_columns([col1, col2, col3, col4, col5]);
            gridView.set_allowPaging(true);
            gridView.set_caption("Validate the value on the server side");
            JData.JQueryUIStyle(gridView);
            gridView.initialize();
        });

完整代码下载以及在线演示请访问 http://jdata.alinq.org