如何将集合绑定到WPF中的ListView [英] How to bind a collection to a ListView in WPF
问题描述
我有一个程序可以在目录中搜索符合特定条件的文件。这个搜索过程需要一个 long 时间，所以我必须异步调用它。当搜索算法找到一个文件时，它触发一个事件。我的 MainWindow 实例监听此事件，需要更新GUI。如何将这些添加文件绑定到一个 ListView ？我想我可以使用 ObservableCollection< FileInfo> 实例，但是我无法弄清楚如何绑定它。
我删除了所有不相关的控件和代码。以下是两个相关文件。
MainWindow.xaml：
< Window x：Class =Example.MainWindow
xmlns =http://schemas.microsoft.com/winfx/2006/xaml/presentation
xmlns：x =http：// schemas.microsoft.com/winfx/2006/xaml
Title =CR SearchHeight =395Width =525>
< Grid>
< ListView x：Name =Results>
< ListView.View>
< GridView>
< GridViewColumn Header =Filename/>
< GridViewColumn Header =Directory/>
< / GridView>
< /ListView.View>
< / ListView>
< / Grid>
< / Window>
MainWindow.xaml.cs：
使用System.IO;
使用System.Threading.Tasks;
public partial class MainWindow
{
private SearchLogic _backgroundSearch;
private async void Search（object sender，RoutedEventArgs e）
{
// TODO：clear结果
_backgroundSearch = new SearchLogic（，新的DirectoryInfo（C：\））;
_backgroundSearch.FileAdded + = FileAdded;
await Task.Run（new Action（_backgroundSearch.Search））;
}
private void FileAdded（object sender，FileAddedEventArgs eventArgs）
{
// TODO：将eventArgs.File添加到结果
// eventArgs。文件是FileInfo的一个实例
}
}
这是一个简单的例子
您的XAML
< Window x：Class =WpfApplication10.MainWindow
xmlns =http://schemas.microsoft.com/winfx/2006/xaml/presentation
xmlns ：x =http://schemas.microsoft.com/winfx/2006/xaml
标题=MainWindow
宽度=525
高度=350
加载=Window_Loaded>
< Grid>
< ListBox ItemsSource ={Binding FileNames}>
< ListBox.ItemTemplate>
< DataTemplate>
< StackPanel Orientation =Vertical>
< Label> Name< / Label>
< TextBlock Text ={Binding Name}/>
< Label> Modified< / Label>
< TextBlock Text ={Binding LastModified}/>
< / StackPanel>
< / DataTemplate>
< /ListBox.ItemTemplate>
< / ListBox>
< / Grid>
< / Window>
您的代码背后
public partial class MainWindow：Window
{
public class FileInfo
{
public string Name {get;组; }
public DateTime LastModified {get;组;
public FileInfo（string name）
{
Name = name;
LastModified = DateTime.Now;
}
}
ObservableCollection< FileInfo> mFileNames = new ObservableCollection< FileInfo>（）;
public ObservableCollection< FileInfo> FileNames
{
get
{
return mFileNames;
}
}
public MainWindow（）
{
DataContext = this;
InitializeComponent（）;
}
private void Window_Loaded（object sender，RoutedEventArgs e）
{
ThreadPool.QueueUserWorkItem（（x）=>
{
while（true）
{
Dispatcher.BeginInvoke（（Action）（（）=>
{
mFileNames.Add（new FileInfo（X））;
}））;
Thread.Sleep（500）;
}
}）;
}
}
如果您运行此问题，您会注意到列表框每半秒更新一次新项目。基本上要注意的是ObservableCollection只能从UI线程更新，所以如果你重构上面的代码，你需要使用当前UI线程的Dispatcher来更新它
I have a program that searches a directory for files matching certain criteria. This search process takes a long time, so I have to call it asynchronously. When the search algorithm finds a file, it triggers an event. My MainWindow instance listens for this event and needs to update the GUI. How can I bind these "added" files to a ListView? I figured that I could use an ObservableCollection<FileInfo> instance, but I can't figure out how to bind it.
I've stripped out all of the irrelevant controls and code. Here are the two relevant files.
MainWindow.xaml:
<Window x:Class="Example.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="CR Search" Height="395" Width="525">
<Grid>
<ListView x:Name="Results">
<ListView.View>
<GridView>
<GridViewColumn Header="Filename"/>
<GridViewColumn Header="Directory"/>
</GridView>
</ListView.View>
</ListView>
</Grid>
</Window>
MainWindow.xaml.cs:
using System.IO;
using System.Threading.Tasks;
public partial class MainWindow
{
private SearchLogic _backgroundSearch;
private async void Search(object sender, RoutedEventArgs e)
{
// TODO: clear Results
_backgroundSearch = new SearchLogic("", new DirectoryInfo("C:\"));
_backgroundSearch.FileAdded += FileAdded;
await Task.Run(new Action(_backgroundSearch.Search));
}
private void FileAdded(object sender, FileAddedEventArgs eventArgs)
{
// TODO: add eventArgs.File to Results
// eventArgs.File is an instance of FileInfo
}
}
Here is a simple example
Your XAML
<Window x:Class="WpfApplication10.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Width="525"
Height="350"
Loaded="Window_Loaded">
<Grid>
<ListBox ItemsSource="{Binding FileNames}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<Label>Name</Label>
<TextBlock Text="{Binding Name}"/>
<Label>Modified</Label>
<TextBlock Text="{Binding LastModified}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Window>
Your Code Behind
public partial class MainWindow : Window
{
public class FileInfo
{
public string Name { get; set; }
public DateTime LastModified { get; set; }
public FileInfo(string name)
{
Name = name;
LastModified = DateTime.Now;
}
}
ObservableCollection<FileInfo> mFileNames = new ObservableCollection<FileInfo>();
public ObservableCollection<FileInfo> FileNames
{
get
{
return mFileNames;
}
}
public MainWindow()
{
DataContext = this;
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
ThreadPool.QueueUserWorkItem((x) =>
{
while (true)
{
Dispatcher.BeginInvoke((Action)(() =>
{
mFileNames.Add(new FileInfo("X"));
}));
Thread.Sleep(500);
}
});
}
}
If you run this problem you will notice that the listbox updates every half a second with a new item. Basically the key thing to note is that the ObservableCollection can only be updated from the UI thread so if you refactor the above code you need need to somehow use the Dispatcher of the current UI thread to update it
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