Thanks for reply.

1. I create a instance of XamWebGrid and set a event handler to KeyDown event.
2. set Data (it has 10,000 rows) to XamWebGrid.ItemsSource.
3. select all rows by XamWebGrid.SelectionSettings.SelectedRows.Add

Process takes about 20 sec at step 3.

But, User can select all rows by mouse, "Click first row and Shift-Click last row".
It takes about 0 sec.

So, I say "too slow".

I think SelectedRows.Add is too slow.

Code is this:

using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using Infragistics.Silverlight.Controls;
using Infragistics.Silverlight;

namespace sample
{
    public partial class MainPage : UserControl
    {
        private XamWebGrid webGrid;

        public MainPage()
        {
            InitializeComponent();
        }

        private void ButtonSearch_Click(object sender, RoutedEventArgs e)
        {
            webGrid = new XamWebGrid();
            webGrid.EditingSettings.AllowEditing = EditingType.None;
            webGrid.SelectionSettings.CellClickAction = CellSelectionAction.SelectRow;
            webGrid.SelectionSettings.RowSelection = SelectionType.Multiple;

            webGrid.KeyDown
                += new System.Windows.Input.KeyEventHandler(onKeyDown);

            Grid.SetColumn(webGrid, 1);
            LayoutRoot.Children.Add(webGrid);

            List<sampleWebService.ITEM> testdata = new List<sampleWebService.ITEM>();
            for (int i = 0; i < 10000; ++i)
            {
                sampleWebService.ITEM item = new sampleWebService.ITEM();
                item.ATTR1 = i.ToString();
                testdata.Add(item);
            }
            webGrid.ItemsSource = testdata;
        }

        private void onKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
        {
            // Ctrl-A
            if (e.Key == System.Windows.Input.Key.A
                && System.Windows.Input.Keyboard.Modifiers == System.Windows.Input.ModifierKeys.Control)
            {
                foreach (var x in webGrid.Rows)
                {
                    webGrid.SelectionSettings.SelectedRows.Add(x);
                }
            }
        }
    }
}

Thanks Stoimen.

I hope fix type of "addrange" in next version NetAdvantage for Silverlight.

and I can write:

webGrid.SelectionSettings.SelectedRows.AddRange(webGrid.rows);

or, Add "ctrl-A" action such as DataGrid has.

Thanks.

Hi, 

I agree, that we need to make this simpler in the future, it was just a use case that we overlooked.

However, it is currently possible, with just a little bit of extra work, for now. 

First, create a new class that derives from SelectedRowsCollection. We're going to do this, to expose a protected method, that will make it possible to make Selection quicker:

 public class CustomSelection : SelectedRowsCollection

    {

        public void AddSelectItem(Row r)

        {

            this.SelectItem(r, true);

        }

    }

Now, in a button click, you can do the following:

  private void Button_Click(object sender, RoutedEventArgs e)

        {

            CustomSelection src = new CustomSelection();

            foreach (Row r in this.DataGrid1.Rows)

                src.AddSelectItem(r);

            this.DataGrid1.SelectionSettings.SelectedRows.AddRange(src);

        }

Note, we do plan on making this easier to achieve in the future, but for now, i hope this helps. 

-SteveZ

Hi, Stephan.

Thank  you more information.

I tried your code, and it works.

Time reduced from 20 sec to 8 sec in 10,000 rows data.

It is better solution!

Thanks.

I add a little information.

In First time, this code takes 8 sec:

var src = new CustomSelection();
foreach (Row r in this.XamWebGrid.Rows)
{
   src.AddSelectItem(r);
}

But in second time, it takes 0.03 sec.

I don't know Why it is.

Hi, 

So, when the xamWebGrid loads, it only accesses the data necessary for what it can currently display.  As your scroll, it accesses more data and creates more Rows. 

What you're doing here, is accessing all of your data and creating all of the Row objects associated with the Data at once. 

So depending on the type of ItemsSource you're using, it could take some time to create the rows. Although once they're created, you won't have that problem, thus the performance improvement the second time around. 

Note: i would recommend that you're at least using an IList for your ItemsSource, as that would give much better performance than just an IEnumerable. 

-SteveZ

I understood.

I think I wrote a code that throws away lazy evaluation.

Thanks your detailed explanation.

IList is better than IEnumerable?

Thank you for your advice!