使用文本框过滤Listview

Question

我有一个文本框，应该过滤我的listview，但它不起作用。 数据是正确的，但它不会刷新列表。

XAML：

<TextBox x:Name="txtSearch" Text="{Binding Path=Filter,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" 

<ListView x:Name="Users" ItemsSource="{Binding Path=Items, UpdateSourceTrigger=PropertyChanged}" SelectedValuePath="SValue" SelectedValue="{Binding SelItem.SValue}" SelectedItem="{Binding SelItem}" IsSynchronizedWithCurrentItem="True" SelectedIndex="0">
                    <ListView.View>
                        <GridView>
                            <GridViewColumn DisplayMemberBinding="{Binding Path=usertable_id}" Header="ID" Width="30"/>
                            <GridViewColumn DisplayMemberBinding="{Binding Path=username}" Header="Username" Width="73"/>
                            <GridViewColumn DisplayMemberBinding="{Binding Path=name}" Header="Full Name" Width="100"/>
                            <GridViewColumn DisplayMemberBinding="{Binding Path=filter}" Header="Jira Filter ID" Width="73"/>
                            <GridViewColumn DisplayMemberBinding="{Binding Path=last_login}" Header="Last Loging" Width="100"/>
                        </GridView>
                    </ListView.View>
                </ListView>

我的ViewModel：

        // Get Data from Database.
        DataTable dt = new DataTable();
        baseConfig = XMLUtils.OpenXMLFile<BaseInterfaceConfig>(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, ConfigParameterNames.Config));
        Configuration config = new Configuration(baseConfig);
        Database db = new Database(config.GetConnectionString(eDatabaseType.Customer));
        var userData = db.GetObjectList<UserTableDTO>("Select usertable_id, username, name, company, email, filter, language, GetStatusMail, assigned_project_key, last_login from dbo.UserTable");

        // Show DataTable "UserTable" in Listview.
        view.Users.ItemsSource = userData;

        // Filter
        CvsStaff = new CollectionViewSource();
        CvsStaff.Source = userData;
        CvsStaff.Filter += ApplyFilter;

userData填充了Datatable中的数据。