Prevent sort being set to nothing

[Phil]

I have a simple RadDataGrid with sorting set to... 

    UserSortMode="Single"

    ColumnDataOperationsMode="Inline".

 

Clicking a header for a column goes through three steps. Sort ascending, sort descending and then no sorting. I want to prevent sorting being removed and so clicking the header when it is at sort descending should set it to ascending again. Is this possible?

[Yana]

Hello Phil,

There is no straight-forward way for removing the "no sorting" option, however, you could achieve it by creating a custom ColumnHeaderTapCommand and switching the SortDescriptor in its Execute method. Here is the implementation:

- DataGrid definition:

<grid:RadDataGrid ColumnDataOperationsMode="Inline" x:Name="grid" Grid.Row="2" ItemsSource="{Binding}" UserSortMode="Single">
    <grid:RadDataGrid.SortDescriptors>
        <grid1:PropertySortDescriptor PropertyName="Name"/>
    </grid:RadDataGrid.SortDescriptors>
</grid:RadDataGrid>

- custom ColumnHeaderTapCommand:

public class CustomColumhHeaderTapCommand : DataGridCommand
{
    public CustomColumhHeaderTapCommand()
    {
        this.Id = CommandId.ColumnHeaderTap;
    }

    public override bool CanExecute(object parameter)
    {
        return true;
    }

    public override void Execute(object parameter)
    {
        var propertyDescriptor = this.Owner.SortDescriptors.FirstOrDefault(a => a is PropertySortDescriptor && ((PropertySortDescriptor)a).PropertyName == "Name");
        if (propertyDescriptor != null)
        {
            this.Owner.SortDescriptors.Remove(propertyDescriptor);
            if (propertyDescriptor.SortOrder == SortOrder.Ascending)
            {
                propertyDescriptor.SortOrder = SortOrder.Descending;
                this.Owner.SortDescriptors.Add(propertyDescriptor);
                ((ColumnHeaderTapContext)parameter).Column.SortDirection = SortDirection.Descending;
            }
            else
            {
                propertyDescriptor.SortOrder = SortOrder.Ascending;
                this.Owner.SortDescriptors.Add(propertyDescriptor);
                ((ColumnHeaderTapContext)parameter).Column.SortDirection = SortDirection.Ascending;
            }
        }
    }
}

- Adding the Command:

this.grid.Commands.Add(new CustomColumhHeaderTapCommand());

Have in mind that this is a custom implementation and I cannot guarantee that it will work in all scenarios.
Try it and let me know whether this would work for you.

Regards,
Yana
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