WPF DataGrid source updating on cell changed

Question

I am new to the WPF ,and i use it to build a point of sale system.

I have a DataGrid control in the main window bound to an ObservableCollection of Item, the cashier will enter/scan the items to be sold the default quantity for each item is 1 but it is available for the cashier to change the quantity manually.

Whenever I change the quantity, it should update the total price with the sum of the items' prices when I leave the cell to another cell on the row, but it doesn't happen, the source is updated only when I go to another row not another cell in the same row.

Is there anyway to force the DataGrid to update the source when the cell is changed rather than the row?

Answer 1

Yes, this is possible. Your question is basically the same as DataGrid - change edit behaviour

The code below is mostly from Quartermeister's answer but I added a DependencyProperty BoundCellLevel that you can set when you need a DataGrid binding to be updated when the current cell changes.

public class DataGridEx : DataGrid
{
    public DataGridEx()
    {

    }

    public bool BoundCellLevel
    {
        get { return (bool)GetValue(BoundCellLevelProperty); }
        set { SetValue(BoundCellLevelProperty, value); }
    }

    public static readonly DependencyProperty BoundCellLevelProperty =
        DependencyProperty.Register("BoundCellLevel", typeof(bool), typeof(DataGridEx), new UIPropertyMetadata(false));

    protected override Size MeasureOverride(Size availableSize)
    {
        var desiredSize = base.MeasureOverride(availableSize);
        if ( BoundCellLevel )
            ClearBindingGroup();
        return desiredSize;
    }

    private void ClearBindingGroup()
    {
        // Clear ItemBindingGroup so it isn't applied to new rows
        ItemBindingGroup = null;
        // Clear BindingGroup on already created rows
        foreach (var item in Items)
        {
            var row = ItemContainerGenerator.ContainerFromItem(item) as FrameworkElement;
            row.BindingGroup = null;
        }
    }
}