Conditional Data Binding based on the selected SearchContext

Environment

Product

Telerik WebForms SearchBox for ASP.NET AJAX

Description

How can I assign a different data source to the Telerik WebForms SearchBox based on the selected SearchContext?

I want the users to be able to select a SearchContext. For instance, they could select between Landlords, Tenants, or Owners and make the SearchBox search from the tables/data sources relative to the selected SearchContext.

Solution

The Telerik WebForms SearchBox implements the ICallbackEventHandler Interface and will make a CallBack sending the ID and Parameters in the Request.Form. For more information on the CallBacks, you can check out the Script Callbacks in ASP.NET article.

The following information is sent with the CallBack:

• Request.Form["__CALLBACKID"] - contains the ID of the Control that makes the CallBack.
• Request.Form["__CALLBACKPARAM"] - contains the CallBack parameters.

First, create two Classes that will be used to parse the CallBack parameters.

C#

public class SBCallBackParams
{
    public SBContextItem SelectedContextItem { get; set; }
}

public class SBContextItem
{
    public string Text { get; set; }
    public string Key { get; set; }
}

VB

Public Class SBCallBackParams
    Public Property SelectedContextItem As SBContextItem
End Class

Public Class SBContextItem
    Public Property Text As String
    Public Property Key As String
End Class

In the Page's Load event, listen to the CallBack request and serialize the parameters. Once done, you can setup a condition to assign different data sources to the SearchBox based on the selected SearchContext.

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (IsCallback)
    {
        string callBackId = Request.Form["__CALLBACKID"];
        string callBackParams = Request.Form["__CALLBACKPARAM"];

        if (callBackId == RadSearchBox1.ID)
        {
            AdvancedJavaScriptSerializer serializer = new AdvancedJavaScriptSerializer();
            SBCallBackParams sbCallBackParams = serializer.Deserialize<SBCallBackParams>(callBackParams);
            SBContextItem selectedContextItem = sbCallBackParams.SelectedContextItem;

            if (selectedContextItem != null)
            {
                switch (selectedContextItem.Text)
                {
                    case "Landlords":
                        RadSearchBox1.DataSource = GetLandLors();
                        break;

                    case "Tenants":
                        RadSearchBox1.DataSource = GetTenants();
                        break;

                    case "Owners":
                        RadSearchBox1.DataSource = GetOwners();
                        break;
                }
            }
            else
            {
                RadSearchBox1.DataSource = GetAllData();
            }

            RadSearchBox1.DataBind();
        }
    }
}

VB

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If IsCallback Then
        Dim callBackId As String = Request.Form("__CALLBACKID")
        Dim callBackParams As String = Request.Form("__CALLBACKPARAM")

        If callBackId = RadSearchBox1.ID Then
            Dim serializer As AdvancedJavaScriptSerializer = New AdvancedJavaScriptSerializer()
            Dim sbCallBackParams As SBCallBackParams = serializer.Deserialize(Of SBCallBackParams)(callBackParams)
            Dim selectedContextItem As SBContextItem = sbCallBackParams.SelectedContextItem

            If selectedContextItem IsNot Nothing Then
                Select Case selectedContextItem.Text
                    Case "Landlords"
                        RadSearchBox1.DataSource = GetLandLors()
                    Case "Tenants"
                        RadSearchBox1.DataSource = GetTenants()
                    Case "Owners"
                        RadSearchBox1.DataSource = GetOwners()
                End Select
            Else
                RadSearchBox1.DataSource = GetAllData()
            End If

            RadSearchBox1.DataBind()
        End If
    End If
End Sub