样式化DataGrid行WPF异常

Question

I'm trying to style my grid a little bit. I want to color rows based on information in the each row. I've got this nasty error during this operation. Moreover this is happening during application startup. This my first steps in WPF I'm trying to make some useful logger, but now I hit the huge wall.

Error: Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead.

It is worth mentioning that I'm using static list as ItemSource to grid. Below some code of mine.

<DataGrid DockPanel.Dock="Bottom" Height="Auto" ItemsSource="{Binding Source={x:Static Log:Logger.LogCollection}, Mode=OneWay}" FontSize="12" FontFamily="Segoe UI">
            <i:Interaction.Behaviors>
                <fw:ScrollGridView/>
            </i:Interaction.Behaviors>
            <Style TargetType="{x:Type DataGridRow}">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding LogType}" Value="Info">
                        <Setter Property="Background" Value="Red" />
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </DataGrid>
    </DockPanel>

And the class

public static class Logger
{
    private static ObservableCollection<LogMessage> _logCollection = new ObservableCollection<LogMessage>();

    public static ObservableCollection<LogMessage> LogCollection
    {
        get { return Logger._logCollection; }
        set 
        { 
            if (_logCollection.Count > 500)
            {
                _logCollection.RemoveAt(_logCollection.Count - 1);
            }
            Logger._logCollection = value; 
        }
    }

    public static void Log(string message)
    {
        Log(LogType.Info, message, null);
    }

    public static void Log(LogType type, string message, string exception)
    {
        LogCollection.Add(new LogMessage { Type = type, Time = DateTime.Now, Message = message, Exception = exception });
    }
}

LogMessage:

    public enum LogType
{
    Debug,
    Warning,
    Error,
    Info
}

public class LogMessage
{
    public LogType Type { get; set; }
    public DateTime Time { get; set; }
    public string Message { get; set; }
    public string Exception { get; set; }
}

Thanks!

Answer 1

Make sure you define your Columns for DataGrid in DataGrid.Columns like below and not directly within DataGrid and define your Style in DataGrid.Resource

     <DataGrid>
           <DataGrid.Resources>
              <Style TargetType="{x:Type DataGridRow}">
                   <Style.Triggers>
                      <DataTrigger Binding="{Binding LogType}" Value="Info">
                          <Setter Property="Background" Value="Red" />
                      </DataTrigger>
                </Style.Triggers>
                </Style>
          </DataGrid.Resources>
           <DataGrid.Columns>
                <DataGridTextColumn/>
            </DataGrid.Columns>

       </DataGrid>

Answer 2

It helped!!! Now it looks like this:

<DataGrid DockPanel.Dock="Bottom" Height="Auto" ItemsSource="{Binding Source={x:Static Log:Logger.LogCollection}, Mode=OneWay}" FontSize="12" FontFamily="Segoe UI" AutoGenerateColumns="False">
            <i:Interaction.Behaviors>
                <fw:ScrollGridView/>
            </i:Interaction.Behaviors>
            <DataGrid.Resources>
            <Style TargetType="{x:Type DataGridRow}">
                <Style.Triggers>
                        <DataTrigger Binding="{Binding Type}" Value="Info">
                        <Setter Property="Background" Value="Red" />
                    </DataTrigger>
                </Style.Triggers>
            </Style>
            </DataGrid.Resources>
            <DataGrid.Columns>
                <DataGridTemplateColumn MinWidth="30" Header="Type">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Image Width="16"
                               Height="16"
                               Source="{Binding Path=Type,
                                                UpdateSourceTrigger=PropertyChanged,
                                                Converter={StaticResource ImageTypeConverter}}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTextColumn Header="Time"
                                    Binding="{Binding Time}"/>
                <DataGridTextColumn Header="Message"
                                    Binding="{Binding Message}"
                                    Width="1200">
                    <DataGridTextColumn.ElementStyle>
                        <Style>
                            <Setter Property="TextBlock.TextWrapping" Value="Wrap" />
                        </Style>
                    </DataGridTextColumn.ElementStyle>
                </DataGridTextColumn>
                <DataGridTextColumn Header="Exception"
                                    Binding="{Binding Exception}"
                                    Width="1200">
                    <DataGridTextColumn.ElementStyle>
                        <Style>
                            <Setter Property="TextBlock.TextWrapping" Value="Wrap" />
                        </Style>
                    </DataGridTextColumn.ElementStyle>
                </DataGridTextColumn>
            </DataGrid.Columns>
        </DataGrid>
    </DockPanel>

And I have another one question. Before I have added DataGrid.Resources my behavior worker perfectly and after that the event stopped firing. It is strange because I didn't change way of adding item to my grid source.

    public class ScrollGridView : Behavior<DataGrid>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        this.AssociatedObject.SelectionChanged  += new SelectionChangedEventHandler(AssociatedObject_SelectionChanged);
    }

    private void AssociatedObject_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (sender is DataGrid)
        {
            DataGrid grid = (sender as DataGrid);
            if (grid.Items.Count > 0)
            {
                var border = VisualTreeHelper.GetChild(grid, 0) as Decorator;
                if (border != null)
                {
                    var scroll = border.Child as ScrollViewer;
                    if (scroll != null && !scroll.IsMouseOver) scroll.ScrollToEnd();
                }
            }
        }
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        this.AssociatedObject.SelectionChanged -= new SelectionChangedEventHandler(AssociatedObject_SelectionChanged);
    }
}