TextBlock中的绑定在WPF中不起作用

本文介绍了TextBlock中的绑定在WPF中不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我想动态地更改我的Class中的 TextBlock 文本。

XAML代码：

< TextBlock Name =Footer_textText =/>

C＃：

string footerMainMenuText =设置; Binding set = new Binding（）; set.Mode = BindingMode.OneWay; set.Source = footerMainMenuText; Footer_text.DataContext = footerMainMenuText; Footer_text.SetBinding（TextBlock.TextProperty，set）;

我检查了最后一行，而$ code> Footer_text.Text 设置正确。 （ Footer_text.Text =设置），但在我的应用程序中 TextBlock 不显示设置。这里有什么问题？

解决方案

如果你有约束力 - 为什么不只是在XAML中做？看看你的代码，这是没有意义的 - 你可能只是去

Footer_text.Text =设置;你应该理想地在XAML中做到这一点，或至少提供一些绑定到

的东西。

< TextBlock Text ={Binding SomeProperty}/>

我不知道为什么你会绑定一个字符串在自己的东西...你有没有需要绑定到文本属性的对象？

还使用

Binding（）

这是做什么的？空白路径？不知道绑定目标是什么吗？你尝试过

Binding（）

代替？

编辑：

此外，您的绑定不更新控件的原因可能是因为您没有绑定到实现INotifyPropertyChanged或类似接口的对象。控件需要知道值何时发生变化，所以我想象的是，绑定到'string'的时候不会给TextBlock提供正确的通知。

编辑2 ：

这是绑定工作的一个快速例子：

我的窗口类Window.cs：

< Window x：Class =WpfApplication1.MainWindow xmlns =schemas.microsoft/ winfx / 2006 / xaml / presentation xmlns：x =schemas.microsoft/winfx/2006/xaml Title =MainWindowHeight =350Width = 525> < Grid> < StackPanel> < TextBlock x：Name =txtNameText ={Binding Name}>< / TextBlock> < Button Click =Button_Click>点击我1< / Button> < Button Click =Button_Click_1>点击我2< / Button> < / StackPanel> < / Grid> < / Window>

Window.xaml.cs中的代码

public partial class MainWindow：Window { SomeObjectClass obj = new SomeObjectClass（）; public MainWindow（） { InitializeComponent（）; txtName.DataContext = obj; } private void Button_Click（object sender，RoutedEventArgs e） { obj.Name =Hello World; } private void Button_Click_1（object sender，RoutedEventArgs e） { obj.Name =Goobye World; } }

要绑定到的对象（使用INotifyPropertyChanged） p>

class SomeObjectClass：INotifyPropertyChanged { private string _name =hello; public string Name { get { return _name; } set { _name = value; OnPropertyChanged（Name）; } } public event PropertyChangedEventHandler PropertyChanged; public void OnPropertyChanged（string PropertyName） { if（PropertyChanged！= null） PropertyChanged（this，new PropertyChangedEventArgs（PropertyName））; } }

点击按钮更改SomeObject.Name，但它更新文本框。

I want to dynamically change TextBlock text in my Class.

XAML-Code:

<TextBlock Name="Footer_text" Text=""/>

C#:

string footerMainMenuText = "Setting"; Binding set = new Binding(""); set.Mode = BindingMode.OneWay; set.Source = footerMainMenuText; Footer_text.DataContext = footerMainMenuText; Footer_text.SetBinding(TextBlock.TextProperty, set);

I checked last line, and the Footer_text.Text is set correctly. ( Footer_text.Text="Setting"), but TextBlock in my application doesnt show "Setting". What is the problem here?

解决方案

If you are binding - why not just do it in XAML instead? Looking at your code it's kind of pointless - you might as well just go

Footer_text.Text = "Setting";

You should ideally do it in XAML or at least provide something for it to bind to

<TextBlock Text="{Binding SomeProperty}" />

I'm not sure why you would bind a 'string' on it's own to anything...do you have an object which you need to bind to the text property?

Also using

Binding("")

What does that do? A blank path? Not sure what the binding target would be there... have you tried

Binding()

instead?

Edit:

Also the reason why your binding is not updating the control, is probably because you haven't bound to an object which implements INotifyPropertyChanged or a similar interface. The controls need to know when values have changed, so I'd imagine that binding to 'string' isn't giving the TextBlock the proper notification when it changes

Edit 2:

Here is a quick example of binding working:

My window class Window.cs:

<Window x:Class="WpfApplication1.MainWindow" xmlns="schemas.microsoft/winfx/2006/xaml/presentation" xmlns:x="schemas.microsoft/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <StackPanel> <TextBlock x:Name="txtName" Text="{Binding Name}"></TextBlock> <Button Click="Button_Click">Click me 1</Button> <Button Click="Button_Click_1">Click me 2</Button> </StackPanel> </Grid> </Window>

The code behind in Window.xaml.cs

public partial class MainWindow : Window { SomeObjectClass obj = new SomeObjectClass(); public MainWindow() { InitializeComponent(); txtName.DataContext = obj; } private void Button_Click(object sender, RoutedEventArgs e) { obj.Name = "Hello World"; } private void Button_Click_1(object sender, RoutedEventArgs e) { obj.Name = "Goobye World"; } }

The object to bind to (with INotifyPropertyChanged)

class SomeObjectClass : INotifyPropertyChanged { private string _name = "hello"; public string Name { get { return _name; } set { _name = value; OnPropertyChanged("Name"); } } public event PropertyChangedEventHandler PropertyChanged; public void OnPropertyChanged(string PropertyName) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(PropertyName)); } }

Clicking the buttons changes SomeObject.Name, but it updates the textbox.