Wpf xaml converter parameter

To learn about a local resource, you can go through this article. Our control Binding property will consume this local resource. Note - You need to use Windows. Data namespace in order to use that interface. Select first one, i. Two functions will be added to the class with the names -. Now, we have to write the definition of these two methods. But before that, we must understand what we are going to do in both the methods.

Don't forget to build your project, otherwise you'll see an exception in designer like this. Our project setup and resources are ready. Next step is to bind the IsChecked property of Checkbox with the string of the textbox. We've already written code for that. Now, we just have to mention that code in binding like the following way. View All. Ammar Shaukat Updated date Sep 27, Things we are going to discuss What are value converters? Why do we need them?

This browser is no longer supported. Download Microsoft Edge More info. Contents Exit focus mode. Please rate your experience Yes No. Any additional feedback? Submit and view feedback for This product This page. When you set an attribute value in a XAML file, the initial type of that value is a string in pure text.

A XAML processor needs two pieces of information in order to process an attribute value. The first piece of information is the value type of the property that is being set. Any string that defines an attribute value and that is processed in XAML must ultimately be converted or resolved to a value of that type. If the value is a primitive that is understood by the XAML parser such as a numeric value , a direct conversion of the string is attempted.

If the value is an enumeration, the string is used to check for a name match to a named constant in that enumeration. If the value is neither a parser-understood primitive nor an enumeration, then the type in question must be able to provide an instance of the type, or a value, based on a converted string. This is done by indicating a type converter class. The type converter is effectively a helper class for providing values of another class, both for the XAML scenario and also potentially for code calls in.

NET code. Depending on your familiarity with the underlying XAML concepts, you may already be using type conversion behavior in basic application XAML without realizing it. For instance, WPF defines literally hundreds of properties that take a value of type Point. A Point is a value that describes a coordinate in a two-dimensional coordinate space, and it really just has two important properties: X and Y.

When you specify a point in XAML, you specify it as a string with a delimiter typically a comma between the X and Y values you provide. In this case that is the class PointConverter. The type converter for Point defined at the class level streamlines the markup usages of all properties that take Point.

Without a type converter here, you would need the following much more verbose markup for the same example shown previously:. Whether to use the type conversion string or a more verbose equivalent syntax is generally a coding style choice. Your XAML tooling workflow might also influence how values are set.

Some XAML tools tend to emit the most verbose form of the markup because it is easier to round-trip to designer views or its own serialization mechanism. Existing type converters can generally be discovered on WPF and. This attribute will name the class that is the supporting type converter for values of that type, for XAML purposes as well as potentially other purposes.

Markup extensions and type converters fill orthogonal roles in terms of XAML processor behavior and the scenarios that they are applied to. Although context is available for markup extension usages, type conversion behavior of properties where a markup extension provides a value is generally is not checked in the markup extension implementations.

In other words, even if a markup extension returns a text string as its ProvideValue output, type conversion behavior on that string as applied to a specific property or property value type is not invoked, Generally, the purpose of a markup extension is to process a string and return an object without any type converter involved. One common situation where a markup extension is necessary rather than a type converter is to make a reference to an object that already exists.

At best, a stateless type converter could only generate a new instance, which might not be desirable. In the WPF and. NET Framework implementation of the XAML parser, there are certain types that have native type conversion handling, yet are not types that might conventionally be thought of as primitives. An example of such a type is DateTime. The reason for this is based on how the. NET Framework architecture works: the type DateTime is defined in mscorlib, the most basic library in.