WPF element host is crashing every second time

问题

I have a WPF user control inside windows form project and I have a problem. Every second time my app crashes as element host can't load data in user control.

Same thing happens when I put this in WPF project. Every second time my app starts normally.

Any idea what could be the problem? This is my user control code:

<UserControl x:Class="Fleet_management.Info"
             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" Height="492" Width="578">
    <UserControl.Background>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <GradientStop Color="#FFE2E2E2" Offset="0" />
            <GradientStop Color="White" Offset="1" />
        </LinearGradientBrush>
    </UserControl.Background>

    <UserControl.Resources>
        <XmlDataProvider x:Key="rssData" XPath="//item" Source="******" />
    </UserControl.Resources>

    <Grid Margin="3" Height="598" Width="565">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="252*" />
            <ColumnDefinition Width="90*" />
            <ColumnDefinition Width="223*" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="177*" />
            <RowDefinition Height="55*" />
            <RowDefinition Height="122*" />
            <RowDefinition Height="177*" />
        </Grid.RowDefinitions>

        <ListBox x:Name="lstItems" Margin="3,0" ItemsSource="{Binding Source={StaticResource rssData}}"
                 SelectedIndex="0" VerticalAlignment="Stretch" FontStretch="Normal" FontSize="14" FontFamily="Lucida Sans Unicode" Grid.ColumnSpan="3">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <Image Width="20" Margin="3" Source="{Binding XPath=enclosure/@url}" />
                        <TextBlock Margin="3" VerticalAlignment="Center" Text="{Binding XPath=title}" FontWeight="Bold" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

        <StackPanel Grid.Row="1" Orientation="Vertical" DataContext="{Binding ElementName=lstItems, Path=SelectedItem}" Margin="0,0,0,5" Grid.ColumnSpan="3">
            <TextBlock Margin="3" FontSize="13" FontWeight="Bold" Text="{Binding XPath=title, Path=InnerText}" />
            <TextBlock Margin="3" Opacity="0.72" Text="{Binding XPath=pubDate}" />
        </StackPanel>
        <ScrollViewer CanContentScroll="True" Grid.Row="2" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto"  DataContext="{Binding ElementName=lstItems, Path=SelectedItem}" Margin="0,0,3,115" Grid.RowSpan="2" Grid.ColumnSpan="3">
            <TextBlock  Margin="3"
                       FontStyle="Italic" Text="{Binding XPath=description, Path=InnerText}" TextWrapping="Wrap" TextAlignment="Justify" AllowDrop="False"
                       Foreground="#FF0000E7" FontFamily="Lucida Sans Unicode" FontSize="14" Padding="0,0,5,0" VerticalAlignment="Center" />
        </ScrollViewer>

    </Grid>
</UserControl>

回答1:

You might want to check if the xml document that contains the data is still locked by the previous app.

So, start up the app. Close it. Check to see if the xml file is still in use.

Also,: add exception handling so you know what exception is being thrown. Use at least Application.DispatherUnhandledException

来源：https://stackoverflow.com/questions/10765116/wpf-element-host-is-crashing-every-second-time