ASP.Net DomainDataSource with Select Parameters
ASP.Net DomainDataSource with Select Parameters
Continuing with .Net RIA Services with Silverlight and ASP.Net. In the last port I wrote about Using DomainDataSource in ASP.Net, and showed its basic usage. In this post I’ll show a more advanced scenario in which you want to use a domain service select method that takes parameters, and get the parameter value from a control on the form.
In the previous post, we had a GridView bound to a DomainDataSource that called a Select Method on the DomainService.
<asp:GridView runat="server" ID="GridView"
AutoGenerateColumns="true"
DataSourceID="customersDataSource">
</asp:GridView>
<asp:DomainDataSource runat="server" ID="customersDataSource"
DomainServiceTypeName="Samples.Bank.Domain.BankDomainService"
SelectMethod="GetCustomers">
</asp:DomainDataSource>
The output was:
Now we want to filter the output list by the City property. To do that, we first have to add a method in our Domain Service that returns the data filtered by a city parameter.
public class BankDomainService : LinqToSqlDomainService<BankDataContext>
{
public IQueryable<Customer> GetCustomers()
{
return this.Context.Customers;
}
public IQueryable<Customer> GetCustomersByCity(string city)
{
if (city == null)
return GetCustomers();
return GetCustomers().Where(c => c.City == city);
}
...
}
Notice that GetCustomersByCity method uses the GetCustomers method that returns an IQueryable<Customer> and filters the result by city.
To select which city we want to filter by, lets add a ListBox with some items:
<asp:ListBox ID="lstCities" AutoPostBack="true" runat="server">
<asp:ListItem>Tel Aviv</asp:ListItem>
<asp:ListItem>Raanana</asp:ListItem>
<asp:ListItem>Ramat Gan</asp:ListItem>
</asp:ListBox>
Note that I had to specify AutoPostBack=”true” in make any change to the filter, since this is a server control.
Now, in order to filter the data source according to the domain method with the select parameter I have to specify a SelectParameter that takes its value from the ListBox, and change the select method to execute.
<asp:DomainDataSource runat="server" ID="customersDataSource"
DomainServiceTypeName="Samples.Bank.Domain.BankDomainService"
SelectMethod="GetCustomersByCity">
<SelectParameters>
<asp:ControlParameter Name="city" ControlID="lstCities"
PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:DomainDataSource>
Now, If we run the application, we can select items in the ListBox, and the items in the GridView will be filtered by the city value.
Enjoy!