WPF DataGrid多Image显示, 导致"没有足够的内存继续执行程序"问题

在DataGrid中使用Image控件显示数据库图片，并设定其ToolTip显示放大图，若记录数量较多，在列表显示后多次显示ToolTip，导致软件提示没有足够的内存继续执行程序 异常，解决方法：设定其绑定模式为OneTime。

<DataGrid Grid.Row="2" FontSize="14" x:Name="dgDetail"
                                      ItemsSource="{Binding}"
                                      AutoGenerateColumns="False" IsReadOnly="True" 
                                      GridLinesVisibility="All"
                                      SelectionUnit="FullRow"
                                      RowDetailsVisibilityMode="VisibleWhenSelected"
                                      ScrollViewer.CanContentScroll="False"
                                      VerticalGridLinesBrush="{DynamicResource {x:Static SystemColors.MenuHighlightBrushKey}}"
                                      ColumnHeaderStyle="{StaticResource HeaderStyle}">
            <DataGrid.Columns>
                <DataGridTextColumn Header="#" Binding="{Binding rownum}"  Width="Auto"/>
                <DataGridTextColumn Header="id" Binding="{Binding Path=id}" Width="Auto" Visibility="Hidden"/>
                <DataGridTemplateColumn Header="图像" Width="80">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Image Source="{Binding roi_pic, Converter={StaticResource covBytesToImageSource}, Mode=OneTime}">
                                <Image.ToolTip>
                                    <DockPanel Width="300" Height="300">
                                        <Image Source="{Binding roi_pic, Converter={StaticResource covBytesToImageSource}, Mode=OneTime}"/>
                                    </DockPanel>
                                </Image.ToolTip>
                            </Image>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
            </DataGrid.Columns>
        </DataGrid>

字节转换为ImageSource

    /// <summary>
    /// 字节数组转换为ImageSource
    /// </summary>
    public class Convert_BytesToImageSource : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            BitmapImage bi = new BitmapImage();

            if (value is byte[] bytes)
            {
                try
                {
                    MemoryStream ms = new MemoryStream();
                    bi.BeginInit();
                    ms.Write(bytes, 0, bytes.Length);
                    ms.Seek(0, SeekOrigin.Begin);
                    bi.StreamSource = ms;
                    bi.EndInit();
                }
                catch
                {

                }
            }

            return bi;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }