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DataGrid ValidationRule or IDataErrorInfo validation code called multiple times for each data change

Posted By:      Posted Date: August 29, 2010    Points: 0   Category :WPF
Following my enquiry regarding a problem in Datagrid validation, for which managing exceptions is apparently a problem, I tested the two other methods: using validation rules, or implementing the IDataErrorInfo interface. I ran into other problems there, more insidious this time. This has been done on Windows7 (32-bit), .NET 4.0.30319. 1) IDataErrorInfo When this interface is implemented, the this[string columnName] property is called four times for each modification: two times before the cell enters edit mode (with the old value in the corresponding property) two times when the new value has to be validated (with the new value) It strikes me as not really efficient, is there something wrong with my code? Here's the C# part: using System; using System.Windows; using System.Collections.ObjectModel; using System.ComponentModel; namespace DataGridTest2 { public partial class MainWindow : Window { ObservableCollection<User> users; public MainWindow() { InitializeComponent(); users = new ObservableCollection<User>() { new User { Name = "Teddy", Age = "2" }, new User { Name = "Avi", Age = "19" } }; datagrid.ItemsSource = users; datagrid.Focus(); } } public class User : INotifyPropertyChanged, IDataErrorInfo { string name; public string Name

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