user interface - How to specify units in Dialog Units in 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 simple^r 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.