如何提高向UI添加控件的速度

Question

I have the following code which creates WPF controls and then adds them to a window in a fashion I need. It works decently, but when trying to create 256 (x4 - two textblocks, combo box, textbox) controls it takes a while to display the tab. Window loads fine but I have many tabs and when I click on point setup tab it lags a little before displaying the tab. It only lags the first time I click on the tab, every time after the first it responds immediately.

At first I thought it was a rendering issue, but after much other research I am of the impression C#/WPF doesn't do well with creating a bunch of objects on the fly and adding them to forms.

If I drop the number of items to 50 it responds immediately, 100 is a slight lag and 200 (256) is a little more of a lag and too much to be acceptable to users.

Any experiences with issues like this before and advice for how to fix it or other tips/tricks.

Thanks in advance! Wesley

public static void pointSetup(VirtualizingStackPanel desc, VirtualizingStackPanel map) //Draws point description and point map table in point setup tab
    {
        StackPanel row;
        TextBlock text;
        TextBox textBox;
        ComboBox comboBox;

        Thickness rowSpacing = new Thickness(0, 0, 0, 5);
        Thickness textSpacing = new Thickness(0, 3, 5, 3);
        List<string> list = new List<string>();

        list.Add("xx");
        for (byte i = 0; i < Global.currentZonesToMap; i++)
        {
            list.Add("Zone  " + (i + 1));
        }

        for (short i = 0; i < 256; i++)
        {
            //desc
            row = new StackPanel();
            row.Margin = rowSpacing;
            row.Orientation = Orientation.Horizontal;

            text = new TextBlock();
            text.Text = "Point " + (i + 1);
            text.Margin = textSpacing;
            text.Width = 50;

            textBox = new TextBox();
            textBox.MaxLength = 28;
            textBox.Text = "";
            textBox.Width = 270;

            row.Children.Add(text);
            row.Children.Add(textBox);

            desc.Children.Add(row);

            //map
            row = new StackPanel();
            row.Margin = rowSpacing;
            row.Orientation = Orientation.Horizontal;

            text = new TextBlock();
            text.Text = "Point " + (i + 1);
            text.Margin = textSpacing;
            text.Width = 50;

            comboBox = new ComboBox();
            comboBox.ItemsSource = list;
            comboBox.Width = 270;

            row.Children.Add(text);
            row.Children.Add(comboBox);

            map.Children.Add(row);
        }
    }

New Code (using DataTemplate and ItemsControl)

    public class DevicePoint
    {
        public string desc { get; set; }

        public int zone { get; set; }

        public List<string> zones { get; set; }
    }

    //Initialized all variables and displays UI (constructor)
    public Dispatcher()
    {
        InitializeComponent();

        List<string> opts = new List<string>();
        opts.Add("xx");
        for (byte i = 0; i < Global.currentZonesToMap; i++)
        {
            opts.Add("Zone  " + (i + 1));
        }

        List<DevicePoint> points = new List<DevicePoint>();
        for (short i = 0; i < 256; i++)
            points.Add(new DevicePoint() { desc = "Point " + (i + 1), zone = 0, zones = opts });
        pointDesc.ItemsSource = points;
        pointZoneMap.ItemsSource = points;

        ... other stuff here ...
    }

        <StackPanel>
                <TextBlock Margin="10" FontWeight="Bold" HorizontalAlignment="Center" Text="Point Descriptions" />
                <ScrollViewer Width="360" Margin="30,10,30,10" MaxHeight="405">
                    <ItemsControl Name="pointDesc" Margin="5">
                        <ItemsControl.ItemTemplate>
                            <DataTemplate>
                                <StackPanel VirtualizingStackPanel.IsVirtualizing="True" Margin="0,0,0,5" Orientation="Horizontal">
                                    <TextBlock Margin="0,3,5,3" Width="50" Text="{Binding desc}" />
                                    <TextBox MaxLength="28" Width="270" Text="{Binding desc}" />
                                </StackPanel>
                            </DataTemplate>
                        </ItemsControl.ItemTemplate>
                    </ItemsControl>
                </ScrollViewer>
            </StackPanel>
            <StackPanel Grid.Column="1">
                <TextBlock Margin="10" FontWeight="Bold" HorizontalAlignment="Center" Text="Point - Zone Map" />
                <ScrollViewer Width="360" Margin="30,10,30,10" MaxHeight="405">
                    <ItemsControl Name="pointZoneMap" Margin="5">
                        <ItemsControl.ItemTemplate>
                            <DataTemplate>
                                <StackPanel VirtualizingStackPanel.IsVirtualizing="True" Margin="0,0,0,5" Orientation="Horizontal">
                                    <TextBlock Margin="0,3,5,3" Width="50" Text="{Binding desc}" />
                                    <ComboBox Width="270" ItemsSource="{Binding zones}" SelectedIndex="{Binding zone}" />
                                </StackPanel>
                            </DataTemplate>
                        </ItemsControl.ItemTemplate>
                    </ItemsControl>
                </ScrollViewer>
            </StackPanel>

Answer 1

1. If your computer have multiple cores, and I am assuming it have, try to perform the for loop in parallel (parallelfor (from .net 4 or above).
2. You can set the points List size during creation to 256, this will prevent memory allocations during the items adding operation.
3. Consider use a StringBuilder if Global.currentZonesToMap is large.
4. Use StringBuilder to build the value for the DevicePoint.desc string property.

Good luck,

M. Moshe