C# 在每个新字符上创建 WPF TextBox 绑定？
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Making a WPF TextBox binding fire on each new character?
提问by luddet
How can I make a data binding update as soon as a new character is typed in a TextBox?
在 TextBox 中输入新字符后，如何立即进行数据绑定更新？
I'm learning about bindings in WPF and now I've become stuck on a (hopefully) simple matter.
我正在学习 WPF 中的绑定，现在我陷入了一个（希望如此）简单的问题。
I have a simple FileLister class where you can set a Path property, and then it will give you a listing of files when you access the FileNames property. Here is that class:
我有一个简单的 FileLister 类，您可以在其中设置 Path 属性，然后在您访问 FileNames 属性时它会为您提供文件列表。这是那个类：
class FileLister:INotifyPropertyChanged {
private string _path = "";
public string Path {
get {
return _path;
}
set {
if (_path.Equals(value)) return;
_path = value;
OnPropertyChanged("Path");
OnPropertyChanged("FileNames");
}
}
public List<String> FileNames {
get {
return getListing(Path);
}
}
private List<string> getListing(string path) {
DirectoryInfo dir = new DirectoryInfo(path);
List<string> result = new List<string>();
if (!dir.Exists) return result;
foreach (FileInfo fi in dir.GetFiles()) {
result.Add(fi.Name);
}
return result;
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string property) {
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) {
handler(this, new PropertyChangedEventArgs(property));
}
}
}
I'm using the the FileLister as a StaticResource in this very simple app:
我在这个非常简单的应用程序中使用 FileLister 作为 StaticResource：
<Window x:Class="WpfTest4.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfTest4"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<local:FileLister x:Key="fileLister" Path="d:\temp" />
</Window.Resources>
<Grid>
<TextBox Text="{Binding Source={StaticResource fileLister}, Path=Path, Mode=TwoWay}"
Height="25" Margin="12,12,12,0" VerticalAlignment="Top" />
<ListBox Margin="12,43,12,12" Name="listBox1" ItemsSource="{Binding Source={StaticResource ResourceKey=fileLister}, Path=FileNames}"/>
</Grid>
</Window>
The binding is working. If I change the value in the textbox and then click outside of it, the listbox contents will update (as long as the path exists).
绑定正在工作。如果我更改文本框中的值，然后单击它的外部，则列表框内容将更新（只要路径存在）。
The problem is that I would like to update as soon as a new character is typed, and not wait until the textbox lose focus.
问题是我想在输入新字符后立即更新，而不是等到文本框失去焦点。
How can I do that? Is there a way to do this directly in the xaml, or do I have to handle TextChanged or TextInput events on the box?
我怎样才能做到这一点？有没有办法直接在 xaml 中执行此操作，或者我是否必须处理框上的 TextChanged 或 TextInput 事件？
采纳答案by Dave
In your textbox binding, all you have to do is set UpdateSourceTrigger=PropertyChanged.
在您的文本框绑定中，您所要做的就是设置UpdateSourceTrigger=PropertyChanged.
回答by Eduardo Brites
You have to set the UpdateSourceTriggerproperty to PropertyChanged
您必须将UpdateSourceTrigger属性设置为PropertyChanged
<TextBox Text="{Binding Source={StaticResource fileLister}, Path=Path, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
Height="25" Margin="12,12,12,0" VerticalAlignment="Top"/>
回答by Erhy
Suddenly the data binding between slider and associated TextBox made troubles. At last I found the reason and could fix it. The converter I use:
突然之间滑块和关联的TextBox 之间的数据绑定产生了麻烦。最后我找到了原因并可以解决它。我使用的转换器：
using System;
using System.Globalization;
using System.Windows.Data;
using System.Threading;
namespace SiderExampleVerticalV2
{
internal class FixCulture
{
internal static System.Globalization.NumberFormatInfo currcult
= Thread.CurrentThread.CurrentCulture.NumberFormat;
internal static NumberFormatInfo nfi = new NumberFormatInfo()
{
/*because manual edit properties are not treated right*/
NumberDecimalDigits = 1,
NumberDecimalSeparator = currcult.NumberDecimalSeparator,
NumberGroupSeparator = currcult.NumberGroupSeparator
};
}
public class ToOneDecimalConverter : IValueConverter
{
public object Convert(object value,
Type targetType, object parameter, CultureInfo culture)
{
double w = (double)value;
double r = Math.Round(w, 1);
string s = r.ToString("N", FixCulture.nfi);
return (s as String);
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
string s = (string)value;
double w;
try
{
w = System.Convert.ToDouble(s, FixCulture.currcult);
}
catch
{
return null;
}
return w;
}
}
}
In XAML
在 XAML 中
<Window.Resources>
<local:ToOneDecimalConverter x:Key="ToOneDecimalConverter"/>
</Window.Resources>
further the defined TextBox
进一步定义的 TextBox
<TextBox x:Name="TextSlidVolume"
Text="{Binding ElementName=SlidVolume, Path=Value,
Converter={StaticResource ToOneDecimalConverter},Mode=TwoWay}"
/>
回答by sg6336
Without C#, it's enough in XAML for TextBox, not for class. So, monitoring the property of TextBlock, where writing length of TextBox: Binding Text.Length
如果没有 C#，在 XAML 中用于 TextBox 就足够了，而不是用于类。所以，监控TextBlock的属性，其中TextBox的写入长度： Binding Text.Length
<StackPanel>
<TextBox x:Name="textbox_myText" Text="123" />
<TextBlock x:Name="tblok_result" Text="{Binding Text.Length, ElementName=textbox_myText}"/>
</StackPanel>
