WPF DataGridTextColumn direct edit - wpf

Question

i have very simple DataGridTextColumn which should be modified on doubleclick event.
question is what should be added to avoid exception System.InvalidOperationException: ''EditItem' is not allowed for this view.'
<DataGrid x:Name="DG" ItemsSource="{Binding}" GridLinesVisibility="None" Grid.Column="3" Grid.Row="2">
<DataGrid.Columns>
<DataGridTextColumn Header="Name" Binding="{Binding VariantSet, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" MinWidth="60" />
</DataGrid.Columns>
</DataGrid>
simple class:
Public Class CName
Public Property Name As String = "not editable name"
End Class
on load simply added to datagrid
Private Sub MainWindow_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
Me.DG.Items.Add(New CName)
End Sub
when declared through template as following, there is no difference, same error
<DataGridTemplateColumn Header="Name" IsReadOnly="False">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<TextBox Text="{Binding Name}" />
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>
even when Implements ComponentModel.INotifyPropertyChanged is added to the CName, no difference

Answer 1

You've not shown us enough to tell what you're doing wrong.
Here's a working window with datagrid.
The code is c# but you can run it through a converter to vb if you particularly want vb. I think it's a bad idea for a beginner to choose vb nowadays. Almost nobody publishes samples using vb.
In my mainwindow:
<Window.DataContext>
<local:MainWindowViewModel/>
</Window.DataContext>
<Grid>
<DataGrid AutoGenerateColumns="False"
ItemsSource="{Binding People}">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding FirstName}" Header="First Name"/>
<DataGridTextColumn Binding="{Binding LastName}" Header="SurName"/>
</DataGrid.Columns>
</DataGrid>
</Grid>
That viewmodel:
public class MainWindowViewModel : BaseViewModel
{
private ObservableCollection<Person> people = new ObservableCollection<Person>();
public ObservableCollection<Person> People
{
get { return people; }
set { people = value; }
}
public MainWindowViewModel()
{
People.Add(new Person { FirstName = "Chesney", LastName = "Brown" });
People.Add(new Person { FirstName = "Gary", LastName = "Windass" });
People.Add(new Person { FirstName = "Liz", LastName = "McDonald" });
People.Add(new Person { FirstName = "Carla", LastName = "Connor" });
}
}
Person just has those two properties first and last name:
public class Person : BaseViewModel
{
private string firstName;
public string FirstName
{
get { return firstName; }
set { firstName = value; RaisePropertyChanged(); }
}
private string lastName;
public string LastName
{
get { return lastName; }
set { lastName = value; RaisePropertyChanged(); }
}
That inherits from BaseViewmodel which just implements inotifypropertychanged.
public class BaseViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void RaisePropertyChanged([CallerMemberName] String propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Here I am editing a row