WPF: Code in XAML -> Width={Binding Height}*2?
April 10th, 2008 . by TobiasThis posting consists of two sections:
- cool but not really useable
- really cool and usable
lets start with the non-usable stuff [Code in XAML]:
Whenever you declare your UI in XAML you've to attach event handlers in the code behind file, right? I expected that there has to be another way to attach code as XAML is just XML which is used to generate .cs (g.cs) files. And, tada, there is one:
1 <Window x:Class="App1.Window1"
2 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4 Title="Window1" Height="300" Width="300">
5 <Grid>
6
7 <x:Code>
8 <![CDATA[
9 private void ClickMe(Object sender, RoutedEventArgs e)
10 {
11 MessageBox.Show("This is embedded code from a CDATA section!");
12 }
13 ]]>
14 </x:Code>
15
16 <Button Content="Click me" Click="ClickMe" />
17 </Grid>
18 </Window>
let me cite Uri Geller: unbelievable 
This will become a mess if there's more code involved. On the other hand: It should be possible to use this "approach" together with the XAML loader to implement a new type of plugin system: Your code gets part of the original code. Didn't test it yet and I hope it doesn't work as this might lead to new security holes.
Let's go on with the second, the really usefull, section [Width={Binding Height}*2]:
As there are a lot of guys out there who are a lot smarter than I, let me concentrate on pasting the following links without any error in this post :D:
Both present ways to define converters for WPF in XAML. Yeah, you got it right, no more one-line converters. Now you can create bindings which can not only bind to properties but can also calculate on those properties.
Once again: unbelievable.
I hope this post is as useful for you as the above links were useful for me.
Regards,
-t
I finally decided to write a comment on your blog. I just wanted to say good job. I really enjoy reading your posts.
Tina Russell