How can I speed up adding controls to a WPF grid?

Question

For a personal project, I need to dynamically populate a grid, based on the contents of an array of variable size. I use code along the lines of what is below to do that, and it works well, except that when the array grows large (as in 200 x 200 or more) it becomes slow (20+ secs to populate). It looks like instantiating the buttons is fast, but adding to the grid is slow.
Am I doing anything wrong? Is there anything I could do to speed up the process using the regular WPF grid? Should I look at another control? Thanks in advance for any suggestions.

        int columns=200;
        int rows=200;

        var width = new GridLength(30);
        var height = new GridLength(25);

        for (int column = 0; column < columns; column++)
        {
            var columnDefinition = new ColumnDefinition();
            columnDefinition.Width = width;
            this.TestGrid.ColumnDefinitions.Add(columnDefinition);
        }

        for (int row = 0; row < rows; row++)
        {
            var rowDefinition = new RowDefinition();
            rowDefinition.Height = height;
            this.TestGrid.RowDefinitions.Add(rowDefinition);
        }

        for (int column = 0; column < columns; column++)
        {
            for (int row = 0; row < rows; row++)
            {
                var button = new Button();
                button.Content = row.ToString() + ", " + column.ToString();
                Grid.SetRow(button, row);
                Grid.SetColumn(button, column);
                this.TestGrid.Children.Add(button);
            }
        }

Answer 1

Have you tried surrounding your loop in:

GridView.BeginUpdate();

// add items

GridView.EndUpdate();

Answer 2

Admittedly I'm still getting my chops wet with WPF, but I'm going to go out on a limb here and say that trying to add 40,000 controls is your real bottleneck; not so much as to how you're adding the controls.

Even if you had all 40,000 controls hard coded in your XAML, you'd still end up with a 20+ second load time.

Either this is the world's largest data entry form or a massive Mine Sweeper board ;-)