WPF Datagrid—如何验证多个行并标记所有无效行?

I have a datagrid with rows where the validation depends on his siblings. So far I'm using BindingGroups and a custom ValidationRule to validate multiple rows a the same time. But I can't figure out how to change the appereance of the invalid row entries. I return a ValidationResult and my grid gets a red border but my style gets ignored. I have a datagrid with rows where the validatio