using-xaml-property-element-syntax

# Using XAML Property Element Syntax

Convert long inline bindings to structured Property Element Syntax for improved readability.

## Problem

Inline binding expressions can become horizontally extended and difficult to read:

```xml
<!-- Hard to read: 120+ characters in one line -->
<CheckBox IsChecked="{Binding Path=DataContext.IsAllChecked, UpdateSourceTrigger=PropertyChanged, RelativeSource={RelativeSource AncestorType=DataGrid, Mode=FindAncestor}}"/>
```

## Solution

Split into Property Element Syntax:

```xml
<!-- Readable: Structured and maintainable -->
<CheckBox>
    <CheckBox.IsChecked>
        <Binding Path="DataContext.IsAllChecked"
                 UpdateSourceTrigger="PropertyChanged">
            <Binding.RelativeSource>
                <RelativeSource AncestorType="{x:Type DataGrid}"
                                Mode="FindAncestor"/>
            </Binding.RelativeSource>
        </Binding>
    </CheckBox.IsChecked>
</CheckBox>
```

---

## When to Use

| Condition | Use Property Element Syntax |
|-----------|----------------------------|
| Line > 100 characters | Yes |
| Nested RelativeSource | Yes |
| MultiBinding | Yes |
| Multiple BindingValidationRules | Yes |
| Simple binding | No (keep inline) |

---

## Common Patterns

### RelativeSource Binding

**Inline (avoid):**
```xml
<TextBlock Text="{Binding DataContext.Title, RelativeSource={RelativeSource AncestorType=Window}}"/>
```

**Property Element (preferred):**
```xml
<TextBlock>
    <TextBlock.Text>
        <Binding Path="DataContext.Title">
            <Binding.RelativeSource>
                <RelativeSource AncestorType="{x:Type Window}"/>
            </Binding.RelativeSource>
        </Binding>
    </TextBlock.Text>
</TextBlock>
```

### MultiBinding

```xml
<TextBlock>
    <TextBlock.Text>
        <MultiBinding Converter="{local:FullNameConverter}">
            <Binding Path="FirstName"/>
            <Binding Path="LastName"/>
        </MultiBinding>
    </TextBlock.Text>
</TextBlock