[Silverlight] Work with Cascading Drop-down Lists in the Telerik Gridview Control

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Introduction

How to work with cascading drop-down lists in the Telerik gridview control?

The Solution

I am explaining how to work with cascading drop-down lists in the Telerik gridview control. The overall approach is pretty much the same. To review, when you're working with cascading DropDownList controls, you need to perform these tasks:

• Populate each of the DropDownList controls.
• Pre-select the appropriate value in each list to match what's currently in the data.
• When the user selects a new value in the master dropdown, repopulate the detail dropdown with a new set of dependent values.

Here information about the schema of the tables is involved in this exercise.

Here you go:

Table: City (ID,Name,ContinentCodel)

Table: Continent(Code,Name)

As I say, you can do this in the GridView control in a way similar, but not identical to how you do it in Page. Let's say you have a grid that looks like this in normal mode:

<telerik:radgridview x:name="radGridView" autogeneratecolumns="True">
</telerik:radgridview>

And looks like this:

When configuring columns that time set AutoGenerateColumns="False" and add columns like:

<telerik:radgridview.columns>
        <telerik:gridviewcomboboxcolumn datamemberbinding="
        {Binding ContinentCode, Mode=TwoWay}" header="Continent"
        displaymemberpath="Name" selectedvaluememberpath="Code">
        <telerik:gridviewcomboboxcolumn itemssourcebinding="
        {Binding AvailableCountries}" datamemberbinding="{Binding CountryID}"
        header="Country" displaymemberpath="Name"
        selectedvaluememberpath="ID" width="400">
    </telerik:gridviewcomboboxcolumn></telerik:gridviewcomboboxcolumn>
    </telerik:radgridview.columns>

When Continent changes that time set country using this code: In Continent selection, changed event looks like: Attached event in MainPage Constructor like:

this.AddHandler(RadComboBox.SelectionChangedEvent, 
new Telerik.Windows.Controls.SelectionChangedEventHandler(comboSelectionChanged));

Selection changed event:

void comboSelectionChanged(object sender, RadRoutedEventArgs args)
        {
            RadComboBox comboBox = (RadComboBox)args.OriginalSource;
            
            if (comboBox.SelectedValue==null 
                || comboBox.SelectedValuePath != "Code")
                return;
            
            Location location = comboBox.DataContext as Location;
            location.ContinentCode = (string)comboBox.SelectedValue;
        }