optimizing-wpf-memory

# WPF Memory Optimization

## 1. Freezable Pattern

### Why Freeze?

| Benefit | Description |
|---------|-------------|
| Thread-safe | Can be used across threads |
| No change tracking | Reduces overhead |
| Renderer optimization | Better GPU utilization |

### Basic Usage
```csharp
// Always freeze static resources
var brush = new SolidColorBrush(Colors.Red);
brush.Freeze();

var pen = new Pen(Brushes.Black, 1);
pen.Freeze();
```

### XAML Freeze
```xml
<Window xmlns:po="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options"
        mc:Ignorable="po">
    <Window.Resources>
        <SolidColorBrush x:Key="FrozenBrush" Color="Red" po:Freeze="True"/>
    </Window.Resources>
</Window>
```

### When Freeze Fails
```csharp
if (brush.CanFreeze)
    brush.Freeze();
else
    // Has bindings or animations - cannot freeze
```

### Modifying Frozen Objects
```csharp
var clone = frozenBrush.Clone(); // Creates unfrozen copy
clone.Color = Colors.Blue;
clone.Freeze(); // Freeze again if needed
```

## 2. Common Memory Leaks

### Event Handler Leaks
```csharp
// ❌ LEAK: Static event holds reference
SomeStaticClass.StaticEvent += OnEvent;

// ✅ FIX: Unsubscribe in Unloaded
Unloaded += (s, e) => SomeStaticClass.StaticEvent -= OnEvent;
```

### CompositionTarget.Rendering Leak
```csharp
// ❌ LEAK: Never unsubscribed
CompositionTarget.Rendering += OnRendering;

// ✅ FIX: Always unsubscribe
Loaded += (s, e) => CompositionTarget.Rendering += OnRendering;
Unloaded += (s, e) => CompositionTarget.Rendering -= OnRendering;
```

### Binding Without INotifyPropertyChanged
```csharp
// ❌ LEAK: PropertyDescriptor retained
public string Name { get; set; } // No INPC

// ✅ FIX: Implement INPC
public string Name
{
    get => _name;
    set { _name = value; OnPropertyChanged(); }
}
```

### DispatcherTimer Leak
```csharp
// ❌ LEAK: Timer keeps running
_timer = new DispatcherTimer();
_timer.Tick += OnTick;
_timer.Start();

// ✅ FIX: Stop and cleanup
Unloaded += (s, e) =>
{
    _timer.