Converters

In MVVM, there will be some point where you will need to use converters. Most of these converters are used in any project, so we have decided to add them to Catel. Below is a list of converters and a short description what they are used for.

Note that the behavior of most converters can be inverted by using the ConverterParameter

Linking converters

It is possible to link converters. To link converters, simply set the Link property in xaml:

<catel:NullableValueConverter x:Key="NullableValueConverter" />
 
<catel:BooleanToVisibilityConverter>
    <catel:BooleanToVisibilityConverter.Link>
        <code:NullToBoolConverter Link="{StaticResource NullableValueConverter}" />
    </catel:BooleanToVisibilityConverter.Link>
</catel:BooleanToVisibilityConverter>

Available converters

Name Description
AreEqualMultiValueConverter Converts the comparison of 2 values to a boolean
BooleanToCollapsingVisibilityConverter Convert from bool to Visibility and back.
BooleanToHidingVisibilityConverter Convert from bool to Visibility and back.
BooleanToGrayscaleConverter Converts a boolean to a grayscale saturation value. If the input is false, this converter will return 0, otherwise 1.
BooleanToOppositeBooleanConverter Convert a boolean to it’s inverted value.
BooleanToTextConverter Converts a boolean value to text, for example “yes” and “no”, or “x” and “ “.
BooleanToCollapsingVisibilityConverter Convert from bool to Visibility and back. True returns Visibility.Visible, False returns Visibility.Collapsed.
BooleanToHidingVisibilityConverter Convert from bool to Visibility and back. True returns Visibility.Visible, False returns Visibility.Hidden.
ColorToBrushConverter Converts a color value to a brush and vice versa.
ContainsItemsConverter Convert the count of an ICollection or IEnumerable to true or false, depending on whether the instance contains items.

For an instance which implements ICollection, check Count > 0

For an instance which implements IEnumerable, if the instance can be Enumerated.

CountCollapsedConverter|Converts the ‘count’ of ICollection, string, long, int or short to Visibility.Visible or Visibility.Collapsed

Visible means: ICollection.Count > 0, String.Length > 0 or long, int, short > 0.

CountHiddenConverter|Converts the ‘count’ of ICollection, string, long, int or short to Visibility.Visible or Visibility.Hidden

Visible means: ICollection.Count > 0, String.Length > 0 or long, int, short > 0.

EmptyStringToCollapsingVisibilityConverter|Converts a string to Visibility. If the string is empty, it will return Visibility.Collapsed. EmptyStringToHidingVisibilityConverter|Converts a string to Visibility. If the string is empty, it will return Visibility.Hidden. EnumToCollapsingVisibilityConverter|Converts an enum to Visibility. The allowed values must be defined inside the ConverterParameter as shown below (element will be visible when MyEnumValue is Enum1 or Enum3):

<TextBlock Visibility="{Binding MyEnumValue, Converter={converters:EnumToCollapsingVisibilityConverter}, ConverterParameter=Enum1|Enum3}"/>

If the ConverterParameter starts with !, the element will not be visible for the specified enum values

EnumToHidingVisibilityConverter|Converts an enum to Visibility. The allowed values must be defined inside the ConverterParameter as shown below (element will be visible when MyEnumValue is Enum1 or Enum3):

<TextBlock Visibility="{Binding MyEnumValue, Converter={converters:EnumToHidingVisibilityConverter}, ConverterParameter=Enum1|Enum3}"/>

If the ConverterParameter starts with !, the element will not be visible for the specified enum values

FormattingConverter|Formats the value using the format string provided in the ConverterParameter IsSelectedConverter|Converts a selected value to either true of false. IsSelectedValueConverter|Converts a selected value to either true of false. GetFirstValidationErrorConverter|Converts a collection containing ValidationError objects to return the first error or an empty string in case there are no errors. IsSelectedConverter|Converts a selected value to either true or false. Useful whena mutually exclusive selection must be made. IntToStringConverter|Converts an inteteger to a string and back. LanguageConverter|Converts the string (value) to a translated value using the ILanguageService. The parameter can be specified, then it should be a CultureInfo. MethodToValueConverter|Converts the result of a method to a value. This makes it possible to bind to a method. See Source MultiplyConverter|Calculates the product of given value and factor in parameter. NullableValueConverter|Converts a value to a representive value for nullable. ObjectToDisplayNameConverter|Converts any value to a display name. Uses the DisplayNameAttribute to handle the tough work. PlatformToBooleanConverter|Converts a value of KnownPlatforms to a boolean based on the current platform. This makes it possible to enable / disable functionality in shared projects based on the target platform. ReferenceToBooleanConverter|Converts a reference to a boolean. If the reference is null, it will return false. ReferenceToCollapsingVisibilityConverter|Converts a reference to Visibility. If the reference is null, it will return Visibility.Collapsed. ReferenceToHidingVisibilityConverter|Converts a reference to Visibility. If the reference is null, it will return Visibility.Hidden. ShortDateFormattingConverter|Converts a date to a short date and back. StringToIntConverter|Converts string to an integer and back. ViewModelToViewConverter|Converts a view model to a view. Great way to locate a view based on a view model inside xaml.


Have a question about Catel? Use StackOverflow with the Catel tag!


Discussion