Interface IValueConverter

Namespace: Syncfusion.Data

Assembly: Syncfusion.Linq.iOS.dll

Syntax

public interface IValueConverter

Methods

Convert(Object, Type, Object, CultureInfo)

Convert a value. Called when moving a value from source to target.

Declaration

object Convert(object value, Type targetType, object parameter, CultureInfo culture)

Parameters

Type	Name	Description
System.Object	value	value as produced by source binding
System.Type	targetType	target type
System.Object	parameter	converter parameter
System.Globalization.CultureInfo	culture	culture information

Returns

Type	Description
System.Object	Converted value. System.Windows.DependencyProperty.UnsetValue may be returned to indicate that the converter produced no value and that the fallback (if available) or default value should be used instead. Binding.DoNothing may be returned to indicate that the binding should not transfer the value or use the fallback or default value.

Remarks

The data binding engine does not catch exceptions thrown by a user-supplied converter. Thus any exception thrown by Convert, or thrown by methods it calls and not caught by the Convert, will be treated as a runtime error (i.e. a crash). Convert should handle anticipated problems by returning DependencyProperty.UnsetValue.

ConvertBack(Object, Type, Object, CultureInfo)

Convert back a value. Called when moving a value from target to source. This should implement the inverse of Convert.

Declaration

object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)

Parameters

Type	Name	Description
System.Object	value	value, as produced by target
System.Type	targetType	target type
System.Object	parameter	converter parameter
System.Globalization.CultureInfo	culture	culture information

Returns

Type	Description
System.Object	Converted back value. Binding.DoNothing may be returned to indicate that no value should be set on the source property. System.Windows.DependencyProperty.UnsetValue may be returned to indicate that the converter is unable to provide a value for the source property, and no value will be set to it.

Remarks

The data binding engine does not catch exceptions thrown by a user-supplied converter. Thus any exception thrown by ConvertBack, or thrown by methods it calls and not caught by the ConvertBack, will be treated as a runtime error (i.e. a crash). ConvertBack should handle anticipated problems by returning DependencyProperty.UnsetValue.