How to pass a value to iValueConverter - wpf

Question

I was trying to solve the following problem (and finally succeeded but probably not in the best way). This is how I tried first:
I am showing a treeview with directories and a checkbox with this WPF code:
<Window.DataContext>
<local:ViewModel/>
</Window.DataContext>
<Grid>
<StackPanel Orientation="Horizontal" VerticalAlignment="Center">
<StackPanel.Resources>
<!-- This Style is applied to all TextBlock elements in the command strip area. -->
<Style TargetType="TextBlock">
<Setter Property="VerticalAlignment" Value="Center" />
<Setter Property="Foreground" Value="#EE000000" />
</Style>
<local:ColorConverter x:Key="XcolorConverter" />
</StackPanel.Resources>
<TreeView ItemsSource="{Binding View}">
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type local:Folder}" ItemsSource="{Binding SubFolders}">
<StackPanel Orientation="Horizontal" VerticalAlignment="Center">
<TextBlock Background="{Binding Path=., Converter={StaticResource XcolorConverter}}" Text="{Binding Name}"/>
<CheckBox Focusable="False" IsChecked="{Binding IsChecked}" VerticalAlignment="Center"/>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
</StackPanel>
</Grid>
What I would need to know in the ColorConverter method Convert, below, is the full directory name to color directories which meet a specific criterium. Parameter "value" is a string with the value (MyNameSpace).Folder. If I inspect "value" in the debugger, I also see "Name" which is the directory name (without the preceding full path) displayed in the Treeview's textbox. However, I can not access value:Name within the program (error CS1061: 'object' does not contain a definition for 'Name', I don't understand why I can see it in the debugger but not access it) nor would it help me as I need the full directory path. Within the ViewModel class/code there's a ForEach assigning the directory names to the ObservableCollection Folder. The object parameter is empty; I know I could add ConverterParameter= in the xaml but don't know how to access the actual displayed directory from within that xaml.
How should I change the WPF so my colorConverter.Convert method can access the (full) directory it is displaying at that moment?
public ICollectionView View { get => cvs.View; }
private CollectionViewSource cvs = new CollectionViewSource();
private ObservableCollection<Folder> col = new ObservableCollection<Folder>();
public class Folder
{
public string Name { get; set; }
public ObservableCollection SubFolders { get; set; } = new ObservableCollection();
}
public partial class ColorConverter : IValueConverter
{
private static int count;
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{ // Set color based upon directory, something like if paramater.(directory=c:\\temp")...
return Brushes.Green;
}
}

Answer 1

If I understood correctly what you need:
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
// Validating the type of incoming value
if (value is Folder folder)
{
// Here we work with the folder variable
string name = folder.Name;
// Set color based upon directory, something like if paramater.(directory=c:\\temp")...
return Brushes.Green;
}
// If the received value is not of the Folder type,
// then the converter returns an undefined value.
return DependencyProperty.UnsetValue;
}