Binding.Converter Binding.Converter Binding.Converter Binding.Converter Property

Definition

Gets or sets the converter object that is called by the binding engine to modify the data as it is passed between the source and target, or vice versa.

public : IValueConverter Converter { get; set; }
IValueConverter Converter();

void Converter(IValueConverter converter);
public IValueConverter Converter { get; set; }
Public ReadWrite Property Converter As IValueConverter
<Binding Converter="converterReference"/>

Property Value

The IValueConverter object that modifies the data.

Examples

To use your converter in a binding, first create an instance of your converter class. The following example shows this as a resource in a XAML file.

<UserControl.Resources>
  <local:DateToStringConverter x:Key="Converter1"/>
</UserControl.Resources>
<TextBlock Grid.Column="0" Margin="5,0"
  Text="{Binding Month, Converter={StaticResource Converter1}}"/>
// Custom class implements the IValueConverter interface.
public class DateToStringConverter : IValueConverter
{

    #region IValueConverter Members

    // Define the Convert method to change a DateTime object to 
    // a month string.
    public object Convert(object value, Type targetType, 
        object parameter, string language)
    {
        // The value parameter is the data from the source object.
        DateTime thisdate = (DateTime)value;
        int monthnum = thisdate.Month;
        string month;
        switch (monthnum)
        {
            case 1:
                month = "January";
                break;
            case 2:
                month = "February";
                break;
            default:
                month = "Month not found";
                break;
        }

        // Return the month value to pass to the target.
        return month;
    }

    // ConvertBack is not implemented for a OneWay binding.
    public object ConvertBack(object value, Type targetType, 
        object parameter, string language)
    {
        throw new NotImplementedException();
    }

    #endregion
}
' Custom class implements the IValueConverter interface.
Public Class DateToStringConverter
    Implements IValueConverter

    ' Define the Convert method to change a DateTime object to
    ' a month string.
    Public Function Convert(ByVal value As Object, _
        ByVal targetType As Type, ByVal parameter As Object, _
        ByVal language As System.String) As Object _
        Implements IValueConverter.Convert

        ' value is the data from the source object.
        Dim thisdate As DateTime = CType(value, DateTime)
        Dim monthnum As Integer = thisdate.Month
        Dim month As String
        Select Case (monthnum)
            Case 1
                month = "January"
            Case 2
                month = "February"
            Case Else
                month = "Month not found"
        End Select
        ' Return the value to pass to the target.
        Return month

    End Function

    ' ConvertBack is not implemented for a OneWay binding.
    Public Function ConvertBack(ByVal value As Object, _
        ByVal targetType As Type, ByVal parameter As Object, _
        ByVal language As System.String) As Object _
        Implements IValueConverter.ConvertBack

        Throw New NotImplementedException

    End Function
End Class

Remarks

Create a converter by implementing the IValueConverter interface and implementing the Convert method. That method should return an object that is of the same type as the dependency property that the binding targets, or at least a type that can be implicitly coerced or converted to the target type.

See also