DataGrid Known Issues - Validation Limitations

There are some limitations with cell validation when the ValidationStep is set to UpdatedValue or CommittedValue. If you are using cell validation (either by itself or in conjuction with row validation) and are experiencing issues, we reommend that you use RawProposed or ConvertedProposed instead. Cell validation using IDataErrorInfo is broken in V1 since unfortunately IDataErrorInfo only works at the UpdatedValue or CommittedValue step, and there is no work-around available at this time.

In general, our recommended strategy around validation is that for RowValidationRules, you should use ValidationStep.UpdateValue and ValidationStep.CommitValue, and for CellValidationRules you should use ValidationStep.RawProposedValue and ValidationStep.ConvertedValue.

Last edited Oct 30, 2008 at 12:01 AM by SamanthaMSFT, version 5


trov2k Aug 13, 2009 at 6:21 PM 
How does this affect MVVM applications where validation is technically occuring on a ViewModel? For instance, all the rules are implemented on the properties of the view model (and some hard exception-based rules on the models themselves), and they are simply visually presented by the Validation.Errors[0] property in the grids error template? Is this why I cannot seem to get the tooltip to display on my failed cells? Or do you mean by "cell validation" setting actual validation rules in XAML and on particular cell definitions?

Thanks for the clarification,

klauswiesel Oct 29, 2008 at 10:32 PM 

so when will cell validation will be fixed regarding IDataErrorInfo? Is there a patch planed for the next weeks?

Does this really mean that IDataErrorInfo can not be used for validation at all? Do you have examples to achive it / something similar?