Server-side Programming Overview

Following is a table of the most important properties you should be aware of when working with RadClientDataSource.

General properties

DataSource settings

This represents the client-side "transport" setting of the kendoDataSource and should allow the same type of server configuration to be serialized on theclient in the form of transport settings for the kendoDataSource.

WebServiceDataSourceSettings – holds all the transport settings for update/delete/insert operations. The following table represents the properties that WebServiceDataSourceSettings exposes.

All of the above CRUD operations share the following common settings

<telerik:RadClientDataSource ID="RadClientDataSource1" runat="server">
    <DataSource>
        <WebServiceDataSourceSettings BaseUrl="http://myservice/">
            <Select Url="update" DataType="JSONP" />
        </WebServiceDataSourceSettings>
    </DataSource>
</telerik:RadClientDataSource>

Schema

This represents the client-side "schema" setting of the kendoDataSource. It serves to provide metadata for the underlying types of objects returned from theservice. User can specify property names, their types and other configuration. The following table represents the properties that exposes.

• FieldName - Gets or sets the name of the field from the model.

• OriginalFieldName – Gets or sets the name of the orginal field from the data.

• ParseFunctionName – Gets or sets the name of function which will parse the field value. If not set default parsers will be used.

• Editable – Gets or sets field from the Model is editable. Default is true .

• Nullable – Gets or sets field from the Model is nullable. Default is true .

• DefaultValue – Gets or sets the default value of the field from the model.

• DataType – Gets or sets the corresponding client-side type of the field from the model. Currently enumeration ( ClientDataSourceModelFieldType ) of 4 types: ( String , Number , Boolean , Data ).|

Expressions and aggregates

RadClientDataSource provides various API for controlling the different expressions that can be applied to the data such as filter, sort, group expressions and aggregates.

FilterExpression

FilterExpression - Hierarchical recursive structure that allows defining of nested complex filter expressions. Consists of two types derived from a common abstract base class:

• FieldName - Gets or sets the field name for the operation. Kendo counterpart here.

• Operator - Gets or sets the filtering operator. Lengthy enumeration containing the following values: EqualTo , NotEqualTo , GreaterThan , GreaterThanOrEqualTo , LessThan , LessThenOrEqualTo , Contains , EndsWith , StartsWith . Kendo counterpart here.

• Value - Property containing the value on which to filter the data. The value is of type string .| | ClientDataSourceFilterExpression |Special type of object that allows recursive nesting of the filter expressions. Has the following properties:

• LogicOperator - Gets or sets the filter logic, AND or OR . Default is AND . Kendo counterpart here

• Filters - A collection that can hold both ClientDataSourceFilterEntry and ClientDataSourceFilterExpression types. Allows unlimited nesting of filters. And the kendo counterpart here|

<telerik:RadClientDataSource ID="RadClientDataSource2" runat="server">
    <FilterExpression>
        <telerik:ClientDataSourceFilterExpression LogicOperator="Or">
            <telerik:ClientDataSourceFilterEntry FieldName="A" Operator="EqualTo" Value="1" />
            <telerik:ClientDataSourceFilterEntry FieldName="B" Operator="EqualTo" Value="2" />
        </telerik:ClientDataSourceFilterExpression>
        <telerik:ClientDataSourceFilterEntry FieldName="C" Operator="EqualTo" Value="3" />
    </FilterExpression>
</telerik:RadClientDataSource>

var filter1 = new ClientDataSourceFilterExpression{ LogicOperator= ClientDataSourceFilterLogicOperator.Or};
filter1.Filters.Add(new ClientDataSourceFilterEntry { FieldName = "A", Operator = ClientDataSourceFilterOperator.EqualTo, Value = "1" });
filter1.Filters.Add(new ClientDataSourceFilterEntry { FieldName = "B", Operator = ClientDataSourceFilterOperator.EqualTo, Value = "2" });
RadClientDataSource1.FilterExpression.Filters.Add(filter1);
RadClientDataSource1.FilterExpression.Filters.Add(new ClientDataSourceFilterEntry { FieldName = "C", Operator = ClientDataSourceFilterOperator.EqualTo, Value = "3" });

Dim filter1 = New ClientDataSourceFilterExpression() With { _
Key .LogicOperator = ClientDataSourceFilterLogicOperator.[Or] _
}
filter1.Filters.Add(New ClientDataSourceFilterEntry() With { _
    Key .FieldName = "A", _
    Key .[Operator] = ClientDataSourceFilterOperator.EqualTo, _
    Key .Value = "1" _
})
filter1.Filters.Add(New ClientDataSourceFilterEntry() With { _
    Key .FieldName = "B", _
    Key .[Operator] = ClientDataSourceFilterOperator.EqualTo, _
    Key .Value = "2" _
})
RadClientDataSource1.FilterExpression.Filters.Add(filter1)
RadClientDataSource1.FilterExpression.Filters.Add(New ClientDataSourceFilterEntry() With { _
    Key .FieldName = "C", _
    Key .[Operator] = ClientDataSourceFilterOperator.EqualTo, _
    Key .Value = "3" _
})

The filter value on the server is always string (if the value property is not string it cannot be set through markup and thewhole filter expressions setting in the markup becomes useless). Consider the following filter expression:

<FilterExpression>
    <telerik:ClientDataSourceFilterEntry FieldName="Discontinued" Operator="EqualTo" Value="true" />
</FilterExpression>

By default this will filter the field Discontinued by the value "true" as string, but if the field is of other type (e.g. boolean) this will cause a client-side error from the kendoDataSource. To filter by other types different than string please specify the type of the field in the Schema settings of the control. This will make the RadClientSideDataSource try to parse the value as the specified type! (currently the parsing is done only client-side) Here is what settings are needed in order to filter the Discontinued field by Boolean value instead of string.

<Schema>
    <Model>
        <telerik:ClientDataSourceModelField FieldName="Discontinued" DataType="Boolean" />
    </Model>
</Schema>

The above is valid only for server-side settings. When you apply filter expressions through the client-side API no such issues exist because you set the value property to the same javascript value that you wish to filter on, and there’s no need to specify types in this case.

SortExpressions

SortExpressions - Gets a collection holding the ClientDataSourceSortExpression expressions of the data source. ClientDataSourceSortExpression is the main object of the collection defining one sort expression. Each group expressionprovides the following properties.

• FieldName - Gets or sets the field name for the sort operation.

• SortOrder - Gets or sets the sort order. Enumeration of three values: Asc, Desc and None. Default is None and the setting is not serialized tothe client.

            <SortExpressions>
                <telerik:ClientDataSourceSortExpression FieldName="ProductID" SortOrder="Asc"  />
            </SortExpressions>

Aggregates

Aggregates – Gets a collection holding aggregates settings applied to the whole data of the dataSource. ClientDataSourceAggregate is the main object of the collection defining on aggregate. Each aggregate setting provides the following properties.

• Field - Gets or sets the field name of the aggregate.

• Aggregate - Gets or sets the aggregate function. An enumeration of the following values: Sum, Min, Max, Count, Average. Default is Sum.

            <Aggregates>
                <telerik:ClientDataSourceAggregate Aggregate="Sum" Field="UnitPrice" />
            </Aggregates>

GroupExpressions

GroupExpressions - Get a collection holding the ClientDataSourceGroupExpression expressions of thedata source. ClientDataSourceGroupExpression is the main object of the collection defining one group expression. Each sort expressionprovides the following properties.

• FieldName - Gets or sets the field name for the group operation.

• SortOrder - Gets or sets the sort order. Enumeration of three values: Asc, Desc and None. Default is None and the setting is not serialized to theclient.

• Aggregates - Get a collection of the aggregates settings applied to the current group.

<GroupExpressions>
    <telerik:ClientDataSourceGroupExpression FieldName="ProductName" SortOrder="Asc">
    </telerik:ClientDataSourceGroupExpression>
</GroupExpressions>