UpdateSourceTrigger usage C# WPF

Question

I am currently using this AutoCompleteTextBox in my project: WPFTextBoxAutoComplete

I am binding the TextBox to a List<string> of Employee names. I am doing this like so;

<TextBox 
    Width="250"  Height="50" HorizontalAlignment="Center"
    Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}" 
    behaviors:AutoCompleteBehavior.AutoCompleteItemsSource="{Binding Employees}" 
/>

What I want the TextBox to do is offer a suggestion when the user types in an Employee's name. However, no suggestion appears at all, which leads me to believe that I am not binding the UpdateSourceTrigger properly.

If I am only binding the behaviour to a List<string> then how does the Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}" work when there is no property of the Employee's name? I am a little unsure as to what needs to change to trigger the update source.

The website provides this explanation: Now, every time the "TestText" property of your datacontext is changed, WPFTextBoxAutoComplete will provide you with auto-completion suggestions.

However, I don't believe my DataContext has a "Name" property.

EDIT:

/**** AutoComplete ****/
public static readonly DependencyProperty AutoCompleteTest = DependencyProperty.Register(
"Test", typeof(string), typeof(CompanyManagement), new PropertyMetadata(default(string)));

public string Test
{
    get { return (string)GetValue(AutoCompleteTest); }
    set { SetValue(AutoCompleteTest, value); }
}

TextBox XAML

        <TextBox 
            Width="250"  Height="50" HorizontalAlignment="Center"
            Text="{Binding Test, UpdateSourceTrigger=PropertyChanged}" 
            behaviors:AutoCompleteBehavior.AutoCompleteItemsSource="{Binding Employees}" 
        />

Answer 1

You just need a property called Name in your DataContext with change notification (either with DependencyProperty or INotifyPropertyChanged).

1. With DependencyProperty:

   public static readonly DependencyProperty NameProperty = DependencyProperty.Register(
       "Name", typeof (string), typeof (WhateverClassYouHave), new PropertyMetadata(default(string)));
   
   public string Name
   {
       get { return (string) GetValue(NameProperty); }
       set { SetValue(NameProperty, value); }
   }
   

2. With INotifyPropertyChanged:

   public class WhateverClassYouHave: INotifyPropertyChanged
   
   private string _name;
   public string Name
   {
       get { return _name; }
       set
       {
           _name = value;
           OnPropertyChanged(nameof(Name)); // C# 6 feature
       }
   }
   
   [NotifyPropertyChangedInvocator]
   protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
   {
       PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); // C# 6 feature
   }
   

As you type, the Name property will change, notify the behavior about the change and it will offer you the suggestion.

Result: