Disabling the button based on items selected in the ItemsList - xaml

Question

<Button ToolTip="Duplicate" ToolTipService.ShowOnDisabled="True"
Command="{Binding Path=DuplicateEntityCommand }"
CommandParameter="{Binding ElementName=GridView, Path=SelectedItems}">
<Image Style="{StaticResource toolbarImageStyle}" Source="/OnePlanner;component/Resources/Icons/duplicate.png"></Image>
<Button.Style>
<Style TargetType="{x:Type Button}" BasedOn="{StaticResource {x:Type Button}}">
<Setter Property="IsEnabled" Value="False"/>
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding ElementName=RadGridView, Path=SelectedItems.Count}" Value="1"/>
<Condition Binding="{Binding Path=IsItemListConstainsToyota}" Value="False"/>
</MultiDataTrigger.Conditions>
<Setter Property="IsEnabled" Value="True"/>
</MultiDataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
The button is tied with the GridView. I have to enable this button based on the selection in SelectedItems. If one selects only one items in the grid and that item does not has let say a string with value equal to Toyota, then the button should be enabled.
I have created a method in viewmodel that I use with commandParameter.
private bool IsItemListConstainsToyota(IList<object> itemList)
{
if (itemList.First() is CarList)
{
String carName= ((CarList)itemList.First()).carNameAsString;
if (carName.Equals("Toyota"))
{
return true;
}
}
return false;
}
The code so far I have does not work. Is there anyway to do in XAML or I have to do it in viewModel?

Answer 1

For the Duplicate Entity Command, you can pass Action<object> for CanExecuteAction. If this is false, then your button will be disabled. Try passing the following Action<object> to the CanExecuteParameter in ICommand.
itemList =>
{
return IsItemListConstainsToyota(itemList);
}