WPF数据绑定数据网格过滤/搜索

Question

我有一个WPF应用程序,它使用(当前)本地数据库作为绑定源.使用Visual Studio 2010工具,我有一个LINQ-SQL模型,它充当大多数表单的Datacontext.

我有一个带有TextBox和Datagrid的UserControl.使用表在UserControl.Loaded事件上设置datagrid ItemSource.TextBox分配了一个事件,以便在文本更改并在datagrid上更新ItemSource时对数据库执行查询.

这个问题是查询数据库所需的时间.因为我正在为每次搜索重新分配DataGrid项目源.

1. 我应该在UserControl加载时加载所有记录 - 有没有办法在BackgroundWorker或类似工具中异步加载记录？

2. 我需要在每次搜索后重新分配DataGrid ItemsSource,还是更有效的过滤数据的方法？

谢谢.利亚姆

<UserControl x:Class="Tracker.DocumentsView"
             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" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <DataGrid AutoGenerateColumns="False" Margin="12,34,12,50" Name="dataGrid1">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding Path=ID}" Header="ID" />
                <DataGridTextColumn Binding="{Binding Path=Reference}" Header="Reference" />
                <DataGridTextColumn Binding="{Binding Path=Subject}" Header="Subject" />
            </DataGrid.Columns>
        </DataGrid>

        <TextBox HorizontalAlignment="Left" Margin="64,8,0,0" Name="txtSearchBox" VerticalAlignment="Top" Width="224" TextChanged="txtSearchBox_TextChanged" />
        <TextBlock Text="Search"  HorizontalAlignment="Left" Margin="11,12,0,0" Name="label1" VerticalAlignment="Top" Height="23" />
    </Grid>
</UserControl>

码:

using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

using Tracker.Model;

namespace Tracker
{
    /// <summary>
    /// Interaction logic for DocumentsView.xaml
    /// </summary>
    public partial class DocumentsView : UserControl
    {
        private TrackerDataContext db;

        public DocumentsView()
        {
            InitializeComponent();
            this.Loaded += new RoutedEventHandler(DocumentsView_Loaded);
        }

        void DocumentsView_Loaded(object sender, RoutedEventArgs e)
        {
            db = new TrackerDataContext();
            dataGrid1.ItemsSource = db.Documents;
        }

        private void txtSearchBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            TextBox textbox = sender as TextBox;
            if (textbox != null)
            {
                string searchstr = textbox.Text;
                if (!string.IsNullOrEmpty(searchstr))
                {
                    var filtered = from document in db.Documents
                                   where document.Subject.Contains(searchstr)
                                       || document.Reference.Contains(searchstr)
                                   select document;

                    dataGrid1.ItemsSource = filtered;
                }
                else
                {
                    dataGrid1.ItemsSource = db.Documents;
                }
            }
        }
    }
}

Answer 1

我认为您应该在开始时从数据库加载所有记录,然后在ItemsSource上使用ICollectionView.Filter.那么你就不必做数据库事务了

你应该这样做

    private void txtSearchBox_TextChanged(object sender, TextChangedEventArgs e)
    {
        TextBox textbox = sender as TextBox;
        if (textbox != null)
        {
            _searchstr = textbox.Text;
            if (!string.IsNullOrEmpty(_searchstr))
            {
                ICollectionView view = CollectionViewSource.GetDefaultView(ItemsSource);
                view.Filter = new Predicate<object>(filter);
            }
        }
    }   

    private bool filter(object item)
    {
        if(item.Subject.Contains(_searchstr) || item.Reference.Contains(searchstr))
        {
            return true;
        }
        return false;           
    }

希望这有帮助,Nidal.