How to specify units in Dialog Units in WPF? - wpf

Question

i'm trying to figure out how to layout a simple dialog in WPF using the proper dialog units (DLUs).
i've come up with a simpler example, that cuts straight to the problem:
You can check the Windows UX Guidelines to see where these measurements come from.
The short version is:
dlu = dialog unit
dlu is based on the font size (items change with user's font size)
a horizontal dlu is different from a vertical dlu (dlu's are not square)
This comes from the definition of a dialog unit: the average character is 8dlus high by 4dlus wide.
Georgia 14pt:
If you use a smaller font (i.e. 8pt Tahoma verses 14pt Georgia), the dlus get smaller:
Segoe UI 9pt:
Note: You'll notice that resolution (i.e. dpi) has no impact on the discussion.

Answer 1

You could try creating a Converter which returns the value multiplied by whatever your DLU is
For example, I created a MathConverter (code is here) which would let you specify something like
<Button Height="{Binding Source={x:Static local:Settings.VerticalDLU,
Converter={StaticResource MathConverter},
ConverterParameter=#VALUE*14}"
Width="{Binding Source={x:Static local:Settings.HorizontalDLU,
Converter={StaticResource MathConverter},
ConverterParameter=#VALUE*50}" />
To make it easier to write and read, you can create a class that inherits from Binding and setup a default binding properties so all you have to do is
<Button Height="{local:MyVDluBinding Source=14}"
Width="{local:MyHDluBinding Source=50}" />
I've never tried overwriting a binding with defaults for Converter and ConverterParameter, but I have overwritten a binding for validation purposes so I believe it's possible.
The ValidationBinding I created could be used like Text="{local:ValidationBinding MyProperty}" and automatically set ValidatesOnDataError=True, ValidatesOnException=True, UpdateSourceTarget=PropertyChanged in the bindings.