This example shows how to check if a user enters valid data into a row. Handle the ValidateRow and InvalidRowException events to validate the focused row's data. You can also use the ValidateRowCommand and InvalidRowExceptionCommand properties to maintain a clean MVVM pattern and process the row validate operation in a ViewModel. If the data is invalid, do not allow the user to move focus to another row until the invalid values are corrected.

The Task class implements the IDataErrorInfo interface and allows you to get error descriptions for the entire row and individual cells (data source fields). Error icons appear in cells that contain invalid values. Hover the mouse pointer over an error icon to display a tooltip with an error description.

• MainWindow.xaml (MainWindow.xaml)
• MainWindow.xaml.cs (MainWindow.xaml.vb)

• MainWindow.xaml (MainWindow.xaml)
• MainViewModel.cs (MainViewModel.vb)

• Data Editing and Validation
• Row Validation
• ValidateRow
• InvalidRowException
• ValidateRowCommand
• InvalidRowExceptionCommand

• How to Validate Cell Editors
• How to Implement Attributes-Based Validation
• How to Initialize the New Item Row with Default Values