WPF - DataGrid Column with Width="*", but MinWidth to Fit Contents
What would be the best/right way to have a set of DataGrid columns have proportional width (Width="\*"), but to have their minimum width be at least the width of their content? At the moment, if I use Width="*", then the columns stay exactly proportional, but content gets cropped if the columns get too thin. If I use Width="Auto", then the columns size themselves perfectly to their content, but this makes them all different sizes.
What I want is really a combination of the two, like Width="\*", MinWidth="Auto" so that when there's extra width the columns will all space out to equal widths, but when the grid is made smaller, the content never gets cropped.
Sadly, MinWidth="Auto" doesn't exist, so I guess I need to bind the column's MinWidth property, but it's hard to figure out exactly what I would bind it to.
How do I tell WPF "MinWidth=" the width of the column's widest piece of content?
Answer
I know its a bit late, but I found your question and programmed a pure-XAML solution.
<ColumnDefinition Width="42*" MinWidth="{Binding Path=ActualWidth, ElementName=projectInfoHeader }"/>
Where the ElementName points to the control taking up most of the space. Of course thats only possible to do with elements, that do have a limited width.
If you do it for example for a GroupBox, than you can resize only to larger width and never resize to smaller one.
If you have several candidates for the value of MinWidth, you need to write yourself a IMultiValueConverter, which takes an object[], parses it to floats, and returns the maximum (its just 1 linq query if you use it only yourselves and don't need to handle bad usage of the converter)
This way also supports dynamic changing of the MinWidth.