DP44/docs/ai/Common/DTS.Common/Behaviors.md

---
source_files:
  - Common/DTS.Common/Behaviors/StringMetaDataAttr.cs
  - Common/DTS.Common/Behaviors/TrimTextBoxBehavior.cs
  - Common/DTS.Common/Behaviors/InteractivityTemplate.cs
  - Common/DTS.Common/Behaviors/TextBoxPasteBehavior.cs
  - Common/DTS.Common/Behaviors/MultiSelectionBehavior.cs
generated_at: "2026-04-17T15:36:03.026612+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "36e847a660d89b00"
---

# DTS.Common.Behaviors Namespace Documentation

## 1. Purpose

This module provides a collection of WPF behaviors and utilities for the DTS application. It includes: `StringMetaDataAttr` for attaching string metadata to enums and objects via reflection; `TrimTextBoxBehavior` for automatically trimming whitespace from TextBox input on focus loss; `InteractivityTemplate` and `InteractivityItems` for attaching behaviors and triggers via data templates (enabling MVVM-friendly dynamic interactivity); `TextBoxPasteBehavior` for intercepting paste operations and routing them through custom ICommand implementations; and `MultiSelectionBehavior` for two-way synchronization between a ListBox's selected items and a bound collection, with special optimizations for bulk operations on specific collection types.

---

## 2. Public Interface

### StringMetaDataAttr

```csharp
public class StringMetaDataAttr : Attribute
{
    public string MetaData { get; }
    internal StringMetaDataAttr(string attr);
    public static string GetStringMetaData(object o);
}
```

- **`MetaData`** property: Read-only string containing the metadata value.
- **`StringMetaDataAttr(string attr)`**: Constructor marked `internal`; cannot be instantiated from outside the assembly.
- **`GetStringMetaData(object o)`**: Static method that retrieves the `MetaData` value from a `StringMetaDataAttr` applied to the member represented by `o`. Returns `null` if the object is null, has no matching member, or lacks the attribute.

---

### TrimTextBoxBehavior

```csharp
public class TrimTextBoxBehavior : Behavior<TextBox>
{
    protected override void OnAttached();
    protected override void OnDetaching();
}
```

- **`OnAttached()`**: Subscribes to `AssociatedObject.LostFocus`.
- **`OnDetaching()`**: Unsubscribes from `AssociatedObject.LostFocus`.
- Behavior trims whitespace from `AssociatedObject.Text` on focus loss and calls `UpdateSource()` on the `TextBox.TextProperty` binding expression if the text changed.

---

### InteractivityTemplate

```csharp
public class InteractivityTemplate : DataTemplate
{
}
```

- Empty class inheriting from `DataTemplate`. Serves as a marker/template type for interactivity.

### InteractivityItems

```csharp
public class InteractivityItems : FrameworkElement
{
    public List<TriggerBase> Triggers { get; }
    public List<Behavior> Behaviors { get; }
    
    public static InteractivityTemplate GetTemplate(DependencyObject obj);
    public static void SetTemplate(DependencyObject obj, InteractivityTemplate value);
    public static readonly DependencyProperty TemplateProperty;
}
```

- **`Triggers`**: Lazily-initialized list of `TriggerBase` objects.
- **`Behaviors`**: Lazily-initialized list of `Behavior` objects.
- **`GetTemplate(DependencyObject obj)`**: Gets the attached `InteractivityTemplate`.
- **`SetTemplate(DependencyObject obj, InteractivityTemplate value)`**: Sets the attached `InteractivityTemplate`.
- **`TemplateProperty`**: Attached property. When changed, loads the template content, casts to `InteractivityItems`, and copies all behaviors and triggers to the target element via `Interaction.GetBehaviors()` and `Interaction.GetTriggers()`.

---

### TextBoxPasteBehavior

```csharp
public class TextBoxPasteBehavior
{
    public static readonly DependencyProperty PasteCommandProperty;
    
    public static ICommand GetPasteCommand(DependencyObject target);
    public static void SetPasteCommand(DependencyObject target, ICommand value);
}
```

- **`PasteCommandProperty`**: Attached property of type `ICommand`.
- **`GetPasteCommand(DependencyObject target)`**: Returns the attached `ICommand`.
- **`SetPasteCommand(DependencyObject target, ICommand value)`**: Sets the attached `ICommand`. When set, registers or unregisters a handler for `CommandManager.ExecutedEvent` on the target.
- Internal handler `CommandExecuted` checks if the command is `ApplicationCommands.Paste` or a `RoutedUICommand` with name "Paste". If so, retrieves clipboard text via `Clipboard.GetText()`, executes the attached command (passing the TextBox as parameter), and marks the event handled.

---

### MultiSelectionBehavior

```csharp
public class MultiSelectionBehavior : Behavior<ListBox>
{
    public IList SelectedItems { get; set; }
    public static readonly DependencyProperty SelectedItemsProperty;
    
    protected override void OnAttached();
}
```

- **`SelectedItems`**: Dependency property of type `IList`.