How to Define Summary Rows using AttachedProperty in WPF / UWP DataGrid?

This example illustrates how to define summary rows using AttachedProperty in WPF DataGrid and UWP DataGrid (SfDataGrid).

DataGrid provides support to show the column summary. If the DataContext of DataGrid is ViewModel, you can bind SummaryColumns to a property in ViewModel using the AttachedProperty of type List <GridSummaryColumn>.

Refer to the following code example to define the AttachedProperty of type List <GridSummaryColumn>.

C#

public class SfDataGridAttachedProperty
{
    public static readonly DependencyProperty DynamicSummaryColumnsProperty = DependencyProperty.RegisterAttached("DynamicSummaryColumns",
        typeof(List<GridSummaryColumn>),
        typeof(SfDataGridAttachedProperty)
        , new FrameworkPropertyMetadata(null, OnDynamicSummaryColumnsChanged));

    public static void SetDynamicSummaryColumns(UIElement element, List<GridSummaryColumn> value)
    {
        element.SetValue(DynamicSummaryColumnsProperty, value);
    }
    public static List<GridSummaryColumn> GetDynamicSummaryColumns(UIElement element)
    {
        return (List<GridSummaryColumn>)element.GetValue(DynamicSummaryColumnsProperty);
    }

    private static void OnDynamicSummaryColumnsChanged(DependencyObject d, DependencyPropertyChangedEventArgs args)
    {
        SfDataGrid grid = d as SfDataGrid;

        if (grid.TableSummaryRows.Count() > 1)
        {
            grid.TableSummaryRows.Clear();
        }

        GridTableSummaryRow gsr = new GridTableSummaryRow();
        gsr.ShowSummaryInRow = false;

        var list = ((List<GridSummaryColumn>)args.NewValue);

        foreach (var item in list)
        {
            gsr.SummaryColumns.Add(item);
        }

        grid.TableSummaryRows.Add(gsr);
    }
}

Refer to the following code example to populate GridSummaryColumn in Viewmodel.

C#

internal class ViewModel : INotifyPropertyChanged
{
    private List<GridSummaryColumn> _summarycols;

    public List<GridSummaryColumn> SummaryColumns
    {
        get { return _summarycols; }
        set
        {
            _summarycols = value;
            RaisePropertyChanged("SummaryColumns");
        }
    }

    public ViewModel()
    {
        PopulateEmployeeDetails();
        SetSummaryColumns();
    }

    private void SetSummaryColumns()
    {
        SummaryColumns = new List<GridSummaryColumn>();
        SummaryColumns.Add(new GridSummaryColumn()
        {
            MappingName = "EmployeeID",
            Name = "EmployeeID",
            SummaryType = SummaryType.CountAggregate,
            Format = "Total: {Count}"
        });
        SummaryColumns.Add(new GridSummaryColumn()
        {
            MappingName = "EmployeeSalary",
            Name = "EmployeeSalary",
            SummaryType = SummaryType.DoubleAggregate,
            Format = "Total: {Sum}"
        });
    }
}

Refer to the following code example to bind the attached property in DataGrid.

XAML

<Syncfusion:SfDataGrid x:Name="sfdatagrid"
                       local:SfDataGridAttachedProperty.DynamicSummaryColumns="{Binding SummaryColumns}"
                       ItemsSource="{Binding EmployeeDetails}">
</Syncfusion:SfDataGrid>