Question

I have problems with a .NET 4 application using Bing Maps with custom pushpins. The performance is very bad on zooming or moving the map. I’m using a ObservableCollection which has a data-binding to Bing Maps. Everytime the map changes it is being checked which pushpins are in the map section. The collection will be re-filled and finally a NotifyCollectionChangedEvent is being fired which makes the map draw the pushpins.

<bingMap:MapItemsControl ItemsSource="{Binding Locations}">
    <bingMap:MapItemsControl.ItemTemplate>
        <DataTemplate>
            <bingMap:Pushpin Location="{Binding Coordinates}" Height="Auto" Width="Auto" PositionOrigin="BottomCenter"
                Template="{StaticResource PushpinControlTemplateLoc}">
            </bingMap:Pushpin>
        </DataTemplate>
    </bingMap:MapItemsControl.ItemTemplate>
</bingMap:MapItemsControl >

I made some researches with a performance profiler: The InitializeComponent() method of my custom pushpin class needs an average time of 25% to 35%!

There are usually between 10 and 25 custom pushpins displayed on the map. If I reduce the amount of data bindings it becomes a little bit faster, but still not fast enough.

I’ve already tested out to declare all the brushes as freezed static resources but the drawing still runs very slow.

<SolidColorBrush x:Key="SolidColorBrushUnknownMsg" Color="Gray" ice:Freeze="True"  xmlns:ice="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options" />

I tried to use the Microsoft default pushpins <bingMap:Pushpin Location="{Binding Coordinates}"/> which was much faster. So there must be something wrong in my usage or implementation of my custom pushpin.

Here’s the rest of my code:

Custom pushpin class (only auto-generated code):

public partial class MyPushpin: System.Windows.Controls.Grid
{
    public MyPushpin()
    {
        InitializeComponent();
    }
}

Custom pushpin XAML code:

<Grid x:Class="Test.MyPushpin"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    mc:Ignorable="d">

    <Grid.Resources>
        <Style BasedOn="{StaticResource DataTextBlock}" x:Key="test1" TargetType="TextBlock">
            <Setter Property="Background" Value="{StaticResource SolidColorBrushErrorMsg}"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=TextLine1, Mode=OneWay}" Value="0">
                <Setter Property="Background" Value="{StaticResource BackgroundImage}"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Grid.Resources>

<Border CornerRadius="20" BorderBrush="White" Padding="7" Opacity="0.8" Width="120" Height="100" Background="{StaticResource BackgroundImage}">
    <Grid >
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>

        <TextBlock Grid.Row="0" Grid.Column="0" Text="test2"  Foreground="Black" />
        <TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TextLine2, StringFormat=N1,Mode=OneWay}" Style="{StaticResource DataTextBlock}" />
        <TextBlock Grid.Row="0" Grid.Column="2" Text="{Binding objCurrentPower.sUnit,Mode=OneWay}"  Foreground="Black" />

        <!--three more lines of textblocks with data bindings -->

    </Grid>
</Border>

Why does my custom pushpin need so much performance?

Answer 1

Problem solved: Instead of using a separate class and xaml and referencing to them it’s better to use a ControlTemplate for the custom pushpins in the class the actually contains the Bing Map:

<ControlTemplate x:Key="CutomPushpinTemplate" TargetType="bingMap:Pushpin">
    <Border CornerRadius="15" BorderBrush="White" Padding="7" Opacity="0.8" Width="120" Height="90" Background="{StaticResource Bgr_enercon}">
        <Grid >
            <Grid.RowDefinitions>
                <RowDefinition Height="16" />
                <RowDefinition Height="16" />
                <RowDefinition Height="16" />
                <RowDefinition Height="16" />
                <RowDefinition Height="16" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="45" />
                <ColumnDefinition Width="32" />
                <ColumnDefinition Width="23" />
            </Grid.ColumnDefinitions>

            <TextBlock Grid.Row="0" Grid.Column="0" Text="test2"  Foreground="Black" />
            <TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding TextLine2, StringFormat=N1,Mode=OneWay}" Style="{StaticResource DataTextBlock}" />
            <TextBlock Grid.Row="0" Grid.Column="2" Text="{Binding objCurrentPower.sUnit,Mode=OneWay}"  Foreground="Black" />

            <!--three more lines of textblocks with data bindings -->

        </Grid>
    </Border>
</ControlTemplate>

This template is used for all pushpins of the Bing Map this way:

<bingMap:MapItemsControl ItemsSource="{Binding Locations}">
    <bingMap:MapItemsControl.ItemTemplate>
        <DataTemplate>
            <bingMap:Pushpin Location="{Binding objCoordinates}" Height="Auto" Width="Auto" PositionOrigin="BottomCenter" Template="{StaticResource CutomPushpinTemplate}">
            </bingMap:Pushpin>
        </DataTemplate>
    </bingMap:MapItemsControl.ItemTemplate>

Doing it that way is much faster. The performance profiler shows that the programm now does not spend so much time for instantiating the custom pushpins.

Here is the xaml code which shows how it was implemented before (slow):

<ControlTemplate x:Key="PushpinControlTemplateLoc" TargetType="bingMap:Pushpin" >
    <Test.MyPushpin />
</ControlTemplate>