数据绑定似乎没有刷新 [英] Databindings don't seem to refresh

问题描述

因为某种原因，我真的很努力。我是新来的wpf，我似乎找不到我需要了解这个简单的问题的信息。

我试图将一个文本框绑定到一个字符串，该程序的输出活动。我为字符串创建了一个属性，但是当属性更改时，文本框不会。我有一个列表视图的这个问题，但创建了一个刷新列表视图的调度程序。

我一定缺少一些要点，因为我认为使用wpf的一个好处是不需要手动更新控件。我希望有人可以向我正确的方向发送。

在windowMain.xaml.cs

  private string debugLogText =initial value; 
 
 public String debugLog {
 get {return debugLogText; } 
 set {debugLogText = value; 
} 
  

在windowMain.xaml

  x：Name =wndowMain
 xmlns =http://schemas.microsoft.com/winfx/2006/xaml/presentation
 xmlns ：x =http://schemas.microsoft.com/winfx/2006/xaml
 DataContext ={Binding RelativeSource = {RelativeSource Self}}
 
< TextBox Name = txtDebugText ={Binding ElementName = wndowMain，Path = debugLog}/> 
  

解决方案

在你的课上实现INotifyPropertyChanged。如果你有很多类需要这个接口，我经常会发现使用如下的基类很有帮助。

  public abstract class ObservableObject：INotifyPropertyChanged 
 {
 
 protected ObservableObject（）
 {
} 
 
 public event PropertyChangedEventHandler PropertyChanged; 
 
 protected virtual void OnPropertyChanged（PropertyChangedEventArgs e）
 {
 var handler = PropertyChanged; 
 if（handler！= null）{
 handler（this，e）; 
} 
} 
 
 protected void OnPropertyChanged（string propertyName）
 {
 OnPropertyChanged（new PropertyChangedEventArgs（propertyName））; 
} 
 
} 
  

然后你只需要确保只要属性值更改，就会引发PropertyChanged事件。例如：

  public class Person：ObservableObject {
 
 private string name; 
 
 public string Name {
 get {
 return name; 
} 
 set {
 if（value！= name）{
 name = value; 
 OnPropertyChanged（Name）; 
} 
} 
} 
 
} 
  

For some reason I'm really struggling with this. I'm new to wpf and I can't seem to find the information I need to understand this simple problem.

I am trying to bind a textbox to a string, the output of the programs activity. I created a property for the string, but when the property changes, the textbox does not. I had this problem with a listview, but created a dispatcher which refreshes the listview.

I must be missing some major point, because I thought one benefit of using wpf was not having to update controls manually. I hope someone can send me in the right direction.

in windowMain.xaml.cs

private string debugLogText = "initial value";

public String debugLog {
    get { return debugLogText; }
    set { debugLogText = value; }
}

in windowMain.xaml

x:Name="wndowMain"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
DataContext="{Binding RelativeSource={RelativeSource Self}}"

<TextBox Name="txtDebug" Text="{Binding ElementName=wndowMain, Path=debugLog}" />

解决方案

Implement INotifyPropertyChanged on your class. If you have many classes that need this interface, I often find it helpful to use a base class like the following.

public abstract class ObservableObject : INotifyPropertyChanged
{

    protected ObservableObject( )
    {
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged( PropertyChangedEventArgs e )
    {
        var handler = PropertyChanged;
        if ( handler != null ) {
            handler( this, e );
        }
    }

    protected void OnPropertyChanged( string propertyName )
    {
        OnPropertyChanged( new PropertyChangedEventArgs( propertyName ) );
    }

}

Then you just have to make sure you raise the PropertyChanged event whenever a property value changes. For example:

public class Person : ObservableObject {

    private string name;

    public string Name {
        get {
              return name;
        }
        set {
              if ( value != name ) {
                  name = value;
                  OnPropertyChanged("Name");
              }
        }
    }

}

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