How to enable/disable menuitem (in contextmenu) for a selecteditem of treeview

Question

I need to use a treeview control in WPF application I create nested data (with type DataItem) and assign it to treeview control. Create a hierarchicaldatatemplate and assign it to treeview control Add a contextmenu to treeview, Now I want to disable or enable the menu item by one property of SelectedItem (it should be DataItem, I think), "IsEnabled"

How to approach that?

            <HierarchicalDataTemplate x:Key="dt" ItemsSource="{Binding Items}">
                <TextBlock x:Uid="TextBlock_2" Text="{Binding Name}">
                </TextBlock>
            </HierarchicalDataTemplate>

        <TreeView x:Name="tree_3" Height="200"
                  ItemTemplate="{StaticResource dt}"
                  >
            <TreeView.ContextMenu>
                <ContextMenu>
                    <MenuItem ItemsSource="{Binding SelectedItem}"
                        Header="doA" IsEnabled="{Binding IsEnabled, Mode=OneWay}"  />
                    <MenuItem Header="doB" IsEnabled="False"/>
                    <MenuItem Header="doC" />
                </ContextMenu>
            </TreeView.ContextMenu>
        </TreeView>

class DataItem : DependencyObject //INotifyPropertyChanged
{
    private List<DataItem> _items = new List<DataItem>();
    public List<DataItem> Items 
    {
        get
        {
            return _items;
        }
    }

    public string Name { get; set; }
    public int Category { get; set; }
    public bool IsEnabled { get; set; }
}

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        List<DataItem> allData = new List<DataItem>();

        DataItem i1 = new DataItem() { Name = "Test1", Category = 1, IsEnabled = false };
        DataItem i2 = new DataItem() { Name = "Test2", Category = 2, IsEnabled = false };
        DataItem i3 = new DataItem() { Name = "Test3", Category = 3, IsEnabled = true };

        DataItem t1 = new DataItem() { Name = "Template 1", Category = 1, IsEnabled = true  };
        DataItem t2 = new DataItem() { Name = "Template 2", Category = 1, IsEnabled = false };

        i1.Items.Add(t1);
        i1.Items.Add(t2);

        allData.Add(i1);
        allData.Add(i2);
        allData.Add(i3);
        tree_3.ItemsSource = allData;
    }

I resolved the problem by the following method.

1. create a context menu resource

   <ContextMenu x:Uid="ContextMenu_1" x:Key="TreeViewItemContextMenu"
            ItemsSource="{Binding}">
       <MenuItem x:Uid="MenuItem_1" 
             Header="Rename" 
             IsEnabled="{Binding Path=., Converter={StaticResource renameMenuConverter}}"
             Click="RenameMenu_OnClick"
             />
   </ContextMenu>
   

2. create a style for the tree view item and using the context menu resource above

   <Style TargetType="{x:Type TreeViewItem}" x:Uid="Style_1">
   <Setter x:Uid="Setter_32" Property="ContextMenu" Value="{StaticResource           TreeViewItemContextMenu}">
   </Setter>
   ...
   </Style>
   

3. implement a converter. According to the markup extension above, the parmeter passed in convert is the current selected item, so I can get the property of it and do the checking.

thanks for all of your help.

Answer 1

I have used this in WinForm TreeView with successful results.

When declaring the DataItems also include a tag property in them.

DataItem i1 = new DataItem() { Name = "Test1", 
                  Category = 1, IsEnabled = false, Tag = "Test1" };

On the EventListener for the TreeView, cast sender object or get the SelectedItem from the TreeView.

//It is only Algorithm:
if treeview1.selecedItem.Tag = "Test1" then
    //code for execution
end if

Similarly for the sender object,

//It is only Algorithm:
variable treeNode = cast ( sender to TreeView ).SelectedItem
if treeNode.Tag = "Test1" then
    //code for execution
end if

As for the "code for execution" you can enable or disable the MenuItems.

NOTE: You haven't declared x:Name attribute for the MenuItems in the ContextMenu Tag. Please do that to access the MenuItems.

IsEnabled is the direct property for enabling or disabling the interactable items in WPF

I just gave the algorithm because, I'm more of a VB guy than C#. SO I don't want to mess up with the codes.

Have a great day :)