Listbox with Checkboxes

[Paul Exler]

Hi everyone :)

I have the following situation:
In my GridView, I have a DataColumn with a CellEditTemplate.
In this CellEditTemplate, I need a DataTemplate with a RadDropDownButton, that has a ListBox (with checkboxes) as DropDownContent.

In code it looks like this:

<UserControl.Resources>
        <DataTemplate x:Key="templateLanguagesItem">
            <Grid>
                <CheckBox Name="chkLanguage" Content="{Binding LANGUAGENAME}" d:LayoutOverrides="Width, Height"/>
            </Grid>
        </DataTemplate>
    </UserControl.Resources>


<telerik:RadGridView AutoGenerateColumns="False" HorizontalAlignment="Stretch" Margin="0,30,0,0" Name="grdBenutzer" VerticalAlignment="Stretch" ItemsSource="{Binding ElementName=UserDomainDataSource, Path=Data}">
            <telerik:RadGridView.Columns>
                <telerik:GridViewDataColumn Header="Languages" DataMemberBinding="{Binding LANGUAGES, Mode=TwoWay}" Width="120">
                    <telerik:GridViewDataColumn.CellEditTemplate>
                        <DataTemplate>
                            <StackPanel>

                                <telerik:RadDropDownButton Height="39" Content="Test" VerticalAlignment="Top">
                                    <telerik:RadDropDownButton.DropDownContent>
                                        <ListBox Width="150" Height="200" ItemTemplate="{StaticResource templateLanguagesItem}" ItemsSource="{Binding Data, Source={StaticResource LanguageTestSource}}"/>
                                    </telerik:RadDropDownButton.DropDownContent>
                                </telerik:RadDropDownButton>
                            </StackPanel>
                        </DataTemplate>
                    </telerik:GridViewDataColumn.CellEditTemplate>
                </telerik:GridViewDataColumn>
            </telerik:RadGridView.Columns>
        </telerik:RadGridView>

This works correct. I can open the dropDownButton and get a List of Languages in it with checkboxes.

Now I don't have an idea, how to get the selected checkboxes as one string back in the field "LANGUAGES".
I want to have a string which seperate's the selected items with a comma.

Example:

x Language 1
   Language 2
x Language 3

Now I want a string like "Language 1, Language 3". This should be written in the DataMember of the column.
Hope my explaination is clear.

How can I do this?

[Pavel Pavlov]

Hi Paul Exler,

Since the scenario requires some custom logic to translate the selected values into a coma separated list, the best approach here would be :

Wrap the DropDownButton in a user control and handle this logic in the code-behind of the user control :

1. Create a new User control which has the RadDropDownButton with the Listbox inside.
2. Create a Property for that user control of type string called  SelectedItems
3. In the codebehind of the user control handle the SelecteionChanged event of the ListBox and update the value of the SelectedItems property of your user control whenever that event is raised.

After you have this user control , you just need to place it into the CellTemplate and bind the SelectedItems property two way ,

If this sounds complicated, just let me know and I will prepare a small sample for you . 

Sincerely yours,
Pavel Pavlov
the Telerik team

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[Paul Exler]

Hi Pavel Pavlov,

thank you for your answer.
I get the idea, but I failed to implement this.
I searched for an answer for a while, but don't have an solution.
My main problem is: How to get all the selected checkboxes in the Selectionchanged-Event of the ListBox?
I only get the data items, not my ListBoxItem.

Could you please help me with a small sample. I would be very thankful!

[Pavel Pavlov]

Hello Paul Exler,

I have prepared a small implementation for you to use as a start point. Please find it attached

All the best,
Pavel Pavlov
the Telerik team

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