Using Multi Binding in telerik Datagrid - wpf

Question

How do I pass multiple parameters in command parameters.
here is what I am trying to do:
I want to send Is checked or not (I can do this by introducing a Boolean field to the object bound. But I dont want to do that) and I want to send the selected data object for that row.
<telerik:GridViewColumn.CellTemplate>
<DataTemplate>
<CheckBox Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type telerik:GridViewDataControl}}, Path=DataContext.LineItemSelection}">
<CheckBox.CommandParameter>
<MultiBinding Converter="{StaticResource CommandConverter}">
<Binding Path="IsChecked" />
<Binding RelativeSource="{RelativeSource Self}"/>
</MultiBinding>
</CheckBox.CommandParameter>
</CheckBox>
</DataTemplate>
</telerik:GridViewColumn.CellTemplate>
UPDATE:
I added a class called selection Item. To see what the converter is getting.
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
SelectionItem si = new SelectionItem();
foreach (var value in values)
{
Type t = value.GetType();
if (t.FullName == "System.Boolean")
si.IsSelected = (bool) value;
else
{
si.SelectedCustomer = value as Customer;
}
}
return si;
}
The type of the second parameter is the checkbox itself if I use
<Binding RelativeSource="{RelativeSource Self}"/>
Here I want the data item that is bound to that row(in this case Customer).
I even tried using
<Binding RelativeSource= "{RelativeSource FindAncestor, AncestorType={x:Type telerik:GridViewColumn}}" Path="DataContext" />
But this is also coming in as null. why is this?

Answer 1

Try out simple binding by passing in converter current binding source, then cast to underlying object and based on IsChecked return a value.
<DataTemplate>
<CheckBox Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type telerik:GridViewDataControl}}, Path=DataContext.LineItemSelection}">
<CheckBox.CommandParameter>
<MultiBinding Converter="{StaticResource CommandConverter}">
<Binding Path="IsChecked" />
<Binding RelativeSource="{RelativeSource Self}"/>
</MultiBinding>
</CheckBox.CommandParameter>
</CheckBox>
</DataTemplate>
// CommandConverter should simply return the values
public object Convert(...)
{
return values;
}
Now in command handler you would be able access parameters:
public void OnLineItemSelection(object parameter)
{
object[] parameters = (object[])parameter;
bool isChecked = (double)parameters[0];
var instance = (TYPENAME)parameters[1];
}

Answer 2

using
<CheckBox Name="chkSelection" Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type telerik:GridViewDataControl}}, Path=DataContext.LineItemSelection}">
<CheckBox.CommandParameter>
<MultiBinding Converter="{StaticResource CommandConverter}">
<Binding Path="IsChecked" ElementName="chkSelection" />
<Binding />
</MultiBinding>
</CheckBox.CommandParameter>
</CheckBox>
did the trick