For more information about markup extension behavior, see Markup Extensions and WPF XAML. A markup extension is a XAML feature that lets you specify an object reference by having the markup extension process the attribute string and return the object to a XAML loader. References are created by using either the StaticResource Markup Extension or the DynamicResource Markup Extension. Static and dynamic resourcesĪ resource can be referenced as either static or dynamic. In the previous example, the same MyBrush resource sets two different properties: Button.Background and Rectangle.Fill. And you can reuse the same resource for setting the value of any property that accepts the same type that the resource represents. If you define resources on the root element, all the elements in the logical tree, such as the Window or Page, can access it. If the resource isn't defined on the parent, it continues to check the object's logical tree upward until it's found. If Button doesn't have a definition of the resource key MyBrush (in that example it doesn't its resource collection is empty), the lookup next checks the parent element of Button. In the preceding example, when the XAML loader processes the value for the Background property on Button, the resource lookup logic first checks the resource dictionary for the Button element. For example, use the resource as the value of a property on another element. You can use a defined resource with the resource markup extension syntax that specifies the key name of the resource. Non-string keys for resources are used by certain feature areas in WPF, notably for styles, component resources, and data styling. Typically, the key is a string however, you can also set it to other object types by using the appropriate markup extensions. When you define resources in markup, you assign the unique key through the x:Key Directive. However, resources are most often defined on the root element, which is Window in the example.Įach resource in a resource dictionary must have a unique key. You can define resources on any element, such as a Button. Įvery framework-level element ( FrameworkElement or FrameworkContentElement) has a Resources property, which is a ResourceDictionary type that contains defined resources. The example then references the resource and uses it to set properties of several child elements, including an Ellipse, a TextBlock, and a Button. The following example defines a SolidColorBrush as a resource on the root element of a page. Your converter does not check for this case but instead just converts whatever is passed to string.The Desktop Guide documentation for. For example, if binding fails, WPF will pass DependencyProperty.UnsetValue to your converter. You need to add more checks to your MaddoColorConverter. Public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)Īnd here are some relevant snippets from the form xaml: Var convertedColor = ColorConverter.ConvertFromString(c) If (value != null & !string.IsNullOrWhiteSpace(value.ToString())) Public object Convert(object value, Type targetType, object parameter, CultureInfo culture) Here's the converter code: public class MaddoColorConverter : IValueConverter I made the converter for the ColorPicker from extended WPF toolkit. I made a converter from string to color and back and it works fine when run but on the editor it just throws a "Token is not valid." error and prevents the editor from showing up, really annoying because it prevents me from using the visual editor.
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