Kendo DataSource: How to define “Computed” Propert

问题:

Situation:

• kendo DataSource

  var ordersDataSource = new kendo.data.DataSource({
      type: "odata",
      transport: {
          read: {
              url: "http://localhost/odata.svc/Orders?$expand=OrderDetails"
          }
      },
      schema: {
          type: "json",
          data: function(response){
              return response.value;
          }
          total: function(response){
              return response['odata.count'];
          }
      },
      serverPaging: true,
      serverFiltering: true,
      serverSorting: true
  })
  

• the json data read from the odata source is like:

  {
      odata.metadata: "xxxx",
      odata.count: "5",
      value: [
          {
              OrderId: 1,
              OrderedDate: "2013-02-20",
              OrderInfoA: "Info A",
              OrderInfoB: "Info B"
              OrderDetails: [
                  {
                      OrderDetailId: 6,
                      OrderDetailInfoC: "Info C",
                      OrderDetailInfoD: "Info D"
                  },
                  {
                      //Another OrderDetail's data
                  }
              ]
          },
          {
              // Another Order's data
          }
      ]
  }
  

Question 1:

1.If I wanna define a "computed" property: OrderedDateRelative, which should be the number of days between Today(2013-02-25) and the Day the Order was Created(2013-02-20), Like: "5 days ago", HOW can i achieve this in the client side?

Answer to Question1: http://jsbin.com/ojomul/7/edit

Question 2 --UPDATE--

2.Every Order has its Nested Property OrderDetails, so is it possible to define a Calculated Field for the Nested OrderDetails Property? Like: OrderDetailInfoCAndD for each OrderDetail, and the value should be something like: OrderDetailInfoC + OrderDetailInfoD, which is "Info C Info D"?

Thanks,

dean

回答1:

You can create a calculated field by specifying the model of the data source:

  dataSource = new kendo.data.DataSource({
    data: [
      { first: "John", last: "Doe" }, 
      { first: "Jane", last: "Doe" }
    ],
    schema: {
      model: {
        // Calculated field
        fullName: function() {
          return this.get("first") + " " + this.get("last");
        }
      }
    }
  });

Here is a live demo: http://jsbin.com/ojomul/1/edit

回答2:

Here is a way to use calculated field in Kendo Grid.

var crudServiceBaseUrl = "http://demos.telerik.com/kendo-ui/service",
dataSource = new kendo.data.DataSource({
    transport: {
        read: {
            url: crudServiceBaseUrl + "/Products",
            dataType: "jsonp"
        }
    },
    pageSize: 20,
    schema: {
        model: {
            total: function (item) {
                return this.UnitPrice * this.UnitsInStock;
            }
        }
    }
});

$("#grid").kendoGrid({
    dataSource: dataSource,
    pageable: true,
    height: 550,
    sortable: true,
    filterable: true,
    toolbar: ["create"],
    columns: [
        { field: "UnitPrice", title: "Unit Price"},
        { field: "UnitsInStock", title: "Units In Stock", width: "120px" },
        { field: "total()", title: "Total" }]
});

回答3:

Below an example to use it in a grid. It can then also sort the column.

$("#grid").kendoGrid({ 
    dataSource: {
        data: [
            { first: "John", last: "Doe" }, 
            { first: "Jane", last: "Doe" }
        ],
        schema: {
          model: {
            // Calculated field
            fullName: function() {
              return this.first + " " + this.last;
            },
            fields: {
               first: { type: "string" },
               last: { type: "string" }
            }
          }
        }
    },
    columns: [
        {
            // Trigger function of the Calculated field
            field: "fullName()",
            title: "Fullname"
        },
        {
            field: "first",
            title: "firstname"
        }
    ]
});