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Binding.Converter Property

Gets or sets the converter to use.

Namespace: System.Windows.Data
Assembly: PresentationFramework (in presentationframework.dll)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

public IValueConverter Converter { get; set; }
/** @property */
public IValueConverter get_Converter ()

/** @property */
public void set_Converter (IValueConverter value)

public function get Converter () : IValueConverter

public function set Converter (value : IValueConverter)

<object Converter="myConverter"/>
 myConverter  A resource reference to a class that implements the IValueConverter interface, which includes implementations of the Convert and ConvertBack methods. To refer to a value converter, use the StaticResource markup extension. 

Property Value

A value of type IValueConverter. The default value is a null reference (Nothing in Visual Basic).

A binding implicitly uses a default converter that tries to do a type conversion between the source value and the target value. If a conversion cannot be made, the default converter returns a null reference (Nothing in Visual Basic).

If you want to associate a custom value converter with a binding, you should create a class that implements the IValueConverter interface and supply implementations for the Convert and ConvertBack methods. Value converters can change data from one type to another, translate between cultural details such as character sets, or modify other aspects of their presentation. For examples of typical conversion scenarios, see "Data Conversion" in the Data Binding Overview.

This example shows how to apply conversion to data that is used in bindings.

To convert data during binding, you must create a class that implements the IValueConverter interface, which includes the Convert and ConvertBack methods.

The following example shows the implementation of a date converter that converts the date value passed in so that it only shows the year, the month, and the day. When implementing the IValueConverter interface, it is a good practice to decorate the implementation with a ValueConversionAttribute attribute to indicate to development tools the data types involved in the conversion, as in the following example:

[ValueConversion(typeof(DateTime), typeof(String))]
public class DateConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        DateTime date = (DateTime)value;
        return date.ToShortDateString();
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        string strValue = value.ToString();
        DateTime resultDateTime;
        if (DateTime.TryParse(strValue, out resultDateTime))
        {
            return resultDateTime;
        }
        return value;
    }
}

Once you have created a converter, you can add it as a resource in your Extensible Application Markup Language (XAML) file. In the following example, src maps to the namespace in which DateConverter is defined.

<src:DateConverter x:Key="dateConverter"/>

Finally, you can use the converter in your binding using the following syntax. In the following example, the text content of the TextBlock is bound to StartDate, which is a property of an external data source.

<TextBlock Grid.Row="2" Grid.Column="0" Margin="0,0,8,0"
           Name="startDateTitle"
           Style="{StaticResource smallTitleStyle}">Start Date:</TextBlock>
<TextBlock Name="StartDateDTKey" Grid.Row="2" Grid.Column="1" 
    Text="{Binding Path=StartDate, Converter={StaticResource dateConverter}}" 
    Style="{StaticResource textStyleTextBlock}"/>

The style resources referenced in the above example are defined in the resource section of the sample not shown in this topic. For the complete code sample from which the above code examples were extracted, see Data Binding Demo.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0

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