从xaml wp8创建c＃类的实例

Question

suppose i want to create an ImageButton class that has an Image and 2 ImageSource attribute then create instance of ImageButton in .xaml file, so that I can place it according to my desired layout.

I already tried creating the class in the correct project namespace outside any classes, declare constructor with an empty argument, then in the xaml I added

xmlns:local="clr-namespace:projectNameSpace"
...
<m:ImageButton></ImageButton>

It is not working, then tried other code,

xmlns:m="clr-namespace:projectNameSpace"
...
<m:ImageButton></ImageButton>

but it is said that cannot assigned to the collection, expected type UIElement and the type "ImageButton" does not include any accessible constructor

is there is a way to reference ac# class and create an instance in wp8 xaml ? or is it not possible ?

Answer 1

If you want your class to be part of the UI, you need to derive from one of the subclasses of the UIElement class (basically, any control)

According to the MSDN , the UIElement class shouldn't be directly inherited:

UIElement does not expose a public constructor.
Typically, you don't derive classes from either UIElement or FrameworkElement directly. More typically used base classes for derived custom classes are these classes:
- Specific controls that are not sealed (for example, TextBox)
- Control base classes (Control, ContentControl, UserControl)
- Navigation elements (Page, Frame)
- Panel classes (the base class Panel, or specific non-sealed implementations such as Grid)

In your case, I guess a Button would be the most appropriate class to inherit.

Furthermore, if you want to create a custom control, you need to remember about a visual aspect as well - extending a template of the base control can be a good starting point.