How do I add additional data to a DataGridRowGroupHeader?

Question

I have a DataGrid that is showing some data via a PagedCollectionView with one group definition. I have created a Style for the corresponding DataGridRowGroupHeader under which I have added a ControlTemplate containing an additional TextBlock and a spacing Rectangle. I would like to bind the widths of these controls to the widths of particular columns, but I am struggling to get this working. I would also like to bind the Text property of the TextBlock to a value.

I tried binding the widths via the Width property of a Rectangle in resources but this didn't work (possibly because the Rectangle was never drawn and therefore didn't calculate it's layout).

However, I believe both sets of bindings can be performed with some use of one or more ValueConverter implementations, but I was wondering if there was a better way. Can any of this be achieved through the definition of a ControlTemplate?

Answer 1

After some trial and error I was able to customize my row group headers. The key to unlocking the solution involved both the RowGroupHeaderStyles property and the LoadingRowGroup event on the DataGrid.

By defining one or more styles for the groups, I was able to customize the control template to include additional named elements. I then used the event to gain access to those elements and either set or bind the relevant values to show the information I required. The only stumbling I had related to binding the size of controls, which I eventually worked around by saving a reference to each row and setting those sizes when it was necessary to refresh them rather than relying on bindings. This may be specific to my project so your mileage may vary.