Silverlight 4 Binding Cheatsheet [转]

Path

<TextBlock Text="{Binding Path=PropertyName}" />
<TextBlock Text="{Binding PropertyName}" />

Path : Name of the property on the object in the Datacontext of the page. The Path keyword is optional. The two lines above are functionally identical.

<TextBlock Text="{Binding Path=Instance.PropertyName}" />

If the object in the DataContext has is another object with properties then you can bind to it's properties by using a fullstop.

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ElementName

<TextBox x:Name="SomeTextBox" />
<TextBlock Text="{Binding ElementName=SomeTextBox, Path=Text}" />

ElementName : Specifies another element in the view tree to bind to.
Path : The property on the source element to bind from.

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Converter

<UserControl.Resources>
    <BindingsProject:TextToColourConverter x:Key="TextToColourConverter" />
</UserControl.Resources>

<Grid x:Name="LayoutRoot">
    <StackPanel>
        <TextBox x:Name="SomeTextBox" />
        <TextBlock Text="{Binding ElementName=SomeTextBox, Path=Text}" />
        <TextBlock Text="Test text" 
Foreground="{Binding ElementName=SomeTextBox,Path=Text, Converter={StaticResource TextToColourConverter}}" />
    </StackPanel>
</Grid>

public class TextToColourConverter: IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return someConvertedValue;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return someConvertedBackValue;
    }
}

Converter : StaticResource declared in Resources. Converter is defined in codebehind and implements IValueConverter

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ConverterParameter

<TextBlock Text="Test text" Foreground="{Binding ElementName=SomeTextBox,Path=Text, Converter={StaticResource TextToColourConverter}, ConverterParameter=true}" />
<TextBlock Text="Test text" Foreground="{Binding ElementName=SomeTextBox,Path=Text, Converter={StaticResource TextToColourConverter}, ConverterParameter='Blue'}" />

String parameters can be passed to the value converter. Unfortunately you can not bind to the ConverterParameter.

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String Format

<TextBlock Text="{Binding Path=TimeWorked, StringFormat=hh\\:mm}" />
<TextBlock Text="{Binding Path=TimeWorked, StringFormat='h\\:mm'}" />
<TextBlock Text="{Binding Path=StartDate, StringFormat=D}" />
<TextBlock Text="{Binding Path=StartDate, StringFormat='MMM dd, yyyy'}" />
<TextBlock Text="{Binding Path=StartDate, StringFormat=MMM\ dd\,\ yyyy}" />
<TextBlock Text="{Binding Path=StartDate, StringFormat=yyyy-MM-dd}" />

Use apostrophes to enclose string formats with special characters, or use \ to escape the special character.

Numeric String Formats

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Null Value

<TextBlock Text="{Binding TotalAmount, TargetNullValue=0}" />

If the value from the bound property is null then it will be replaced with the TargetNullValue.

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Indexed Bindings

<StackPanel>
    <TextBlock Text="{Binding Path=SimpleProp1}" />
    <TextBox Text="{Binding Path=ComplexProp[0].SimpleSubProp, Mode=TwoWay}" Width="200" Height="60"/>
    <TextBox Text="{Binding Path=DictionaryCollection[Mineral], Mode=TwoWay}" />
</StackPanel>

You can bind to any collection that has an index (is IEnumerable). If the collection is a key/value collection such as Dictionary or Hash, then the item can be referenced by the item's key.