我的 WPF DataGrids 加载时间总是很长，而且我在网上找不到任何类似的报告，所以我怀疑我做错了什么。现在我确信这一点，因为增加布局复杂性会大大减慢执行速度。在非常简单的布局中，DataGrid 会立即填充，而下面的代码大约需要 3 秒才能执行。
在以下代码中，即使每个单元格未绑定到任何属性并且 AutoGenerateColumns=False，加载 150 行和 11 列也需要约 3 秒的时间。 （我有一个两核 2.6GHz 处理器，有足够的 RAM）。
当 ItemsSource 属性在布局中设置如下时，就会出现瓶颈：
<Window x:Class="datagridtest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Border Background="LightSteelBlue" CornerRadius="10" Margin="10">
<ScrollViewer Margin="10" HorizontalScrollBarVisibility="Auto">
<Grid Margin="10,50,0,0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="auto" />
<RowDefinition Height="auto" />
</Grid.RowDefinitions>
<Expander IsExpanded="True" Name="expander1" Grid.Row="0">
<Grid>
<DataGrid VirtualizingStackPanel.IsVirtualizing="True" AutoGenerateColumns="false" Name="dg" Height="auto" CanUserReorderColumns="False" CanUserResizeColumns="False" CanUserResizeRows="False" CanUserSortColumns="False">
<DataGrid.Columns>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
<DataGridTextColumn >
<DataGridTextColumn.Header >
<TextBlock Width="140" HorizontalAlignment="Center" TextAlignment="Center">untitled<LineBreak/>column</TextBlock>
</DataGridTextColumn.Header>
</DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Expander>
<Expander IsExpanded="true" Grid.Row="1">
<Grid>
<DataGrid AutoGenerateColumns="True" Height="auto" />
</Grid>
</Expander>
<Expander IsExpanded="true" Grid.Row="2">
<Grid>
<DataGrid AutoGenerateColumns="True" Height="auto" />
</Grid>
</Expander>
<Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="121,-42,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click_2" />
</Grid>
</ScrollViewer>
</Border>
using System.Collections.ObjectModel;
namespace datagridtest
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
class row
{
public string Name { get; set; }
public double Age { get; set; }
}
private void button1_Click_2(object sender, RoutedEventArgs e)
{
ObservableCollection<row> src = new ObservableCollection<row>();
for (int i = 0; i < 150; i++)
src.Add(new row { Name = i.ToString(), Age = i / 2 });
dg.ItemsSource = src;
}
}
}
仅当 DataGrid 嵌入 ScrollViewer 中时才会出现此问题，如下所示：
<ScrollViewer>
<Datagrid/>
</ScrollViewer>
这是有道理的，因为此配置会导致同时绘制整个 DataGrid（以便能够正确调整 ScrollViewer 的工作区大小）。本质上，它覆盖了 DataGrid 的内置虚拟化行为，DataGrid 实现了自己的 ScrollBar，因此不必将其所有内容同时放置在布局中。
换句话说，很少需要在 ScrollViewer 中嵌入 DataGrid，因为 DataGrid 有自己的自动滚动功能。
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