Wpf value converter int parameter

It will be my first XAML extension. But I think it's better to make Value an object rather than int , to avoid boxing it each time in ProvideValue. And then, make it private to avoid assigning something illegal directly. Zeus Typically ProvideValue is only called once per markup extension instance, so the boxing should only occur once anyway.

By not doing it in the constructor, I avoid boxing altogether if ProvideValue is never called. As for making Value private, this would preclude using the markup extension in XAML object element syntax: msdn. Your last paragraph is wrong. It's called type conversion and it also applies to properties. The thing is, that Binding. ConverterParameter has no specific type it's just an object so the parser does not know what conversion to apply, hence every literal is just treated as a string.

Don't use value. Use: Convert. ToInt32 parameter. Aliostad Aliostad Why don't you want to use value. In the preceding code, I am checking the text of text box. If it is married then the convert function returns true that will make the check box checked otherwise it will uncheck the checkbox. The convert back function is doing as said above, if the check box is checked it is setting the text of the TextBox to Married and otherwise Unmarried.

To use the converter you need to implement the interface of the converter class in the XAML page of WPF and need to declare the resource. After declaring the resource there is the need to use it with binding. See the following XAML code example. View All. Toggling the Switch causes the corresponding Label to reflect the change:. It's also possible to use Triggers to implement similar changes in the user-interface based on other views.

The Binding class defines a ConverterParameter property, and the Binding markup extension also defines a ConverterParameter property. If this property is set, then the value is passed to the Convert and ConvertBack methods as the parameter argument. Even if the instance of the value converter is shared among several data bindings, the ConverterParameter can be different to perform somewhat different conversions.

The use of ConverterParameter is demonstrated with a color-selection program. The Red , Green , and Blue properties range between 0 and 1. However, you might prefer that the components be displayed as two-digit hexadecimal values. To display these as hexadecimal values in XAML, they must be multiplied by , converted to an integer, and then formatted with a specification of "X2" in the StringFormat property. The first two tasks multiplying by and converting to an integer can be handled by the value converter.

To make the value converter as generalized as possible, the multiplication factor can be specified with the ConverterParameter property, which means that it enters the Convert and ConvertBack methods as the parameter argument:. The Convert converts from a double to int while multiplying by the parameter value; the ConvertBack divides the integer value argument by parameter and returns a double result.

In the program shown below, the value converter is used only in connection with string formatting, so ConvertBack is not used. The type of the parameter argument is likely to be different depending on whether the data binding is defined in code or XAML. If the ConverterParameter property of Binding is set in code, it's likely to be set to a numeric value:. The ConverterParameter property is of type Object , so the C compiler interprets the literal as an integer, and sets the property to that value.

For that reason, the value converter shown above includes a separate GetParameter method that handles cases for parameter being of type double , int , or string. The values of the Red and Green properties are displayed with a Binding markup extension. The Blue property, however, instantiates the Binding class to demonstrate how an explicit double value can be set to ConverterParameter property.

Skip to main content. In the following example, src maps to the namespace in which DateConverter is defined. Finally, you can use the converter in your binding using the following syntax. In the following example, the text content of the TextBlock is bound to StartDate , which is a property of an external data source.

The style resources referenced in the above example are defined in a resource section not shown in this topic.