没有让 INotifyPropertyChanged 示例工作，我想从后面更新文本块

Question

我一直在查看几个 INotifyPropertyChanged 示例，但没有设法使它们中的任何一个在我的项目中工作。当我更改属性的值时，我的文本块中的文本没有更新，我不知道为什么。

public partial class MainWindow : Window, INotifyPropertyChanged
    {

        public event PropertyChangedEventHandler PropertyChanged;

        public MainWindow()
        {
            InitializeComponent();

        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {

            TextTest = "essa";
        }

        private void NotifyPropertyChanged([CallerMemberName] string name="")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(name));
            }
        }
        private string textTest = string.Empty;

        public string TextTest {
            get { return this.TextTest; }
            set { this.textTest = value;
            NotifyPropertyChanged();
            }
        }
    }


<Window x:Class="TestProjectComboboxAndPropertyChanged.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid Height="200">

        <Button Content="Click me" Click="Button_Click" Height="100" VerticalAlignment="Bottom"></Button>
        <TextBlock Text="{Binding Path=TextTest,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" FontSize="55" Height="100" VerticalAlignment="Top"></TextBlock>
    </Grid>
</Window>

Answer 1

您缺少绑定。在您的表单构造函数中，将表单数据上下文绑定到当前实例。

public MainWindow()
    {
        InitializeComponent();
        this.DataContext = this;

    }

Answer 2

这里的问题不是其他人所说的属性名称。根据 INotifyPropertyChanged:

的文档

The PropertyChanged event can indicate all properties on the object have changed by using either null or String.Empty as the property name in the PropertyChangedEventArgs.

因此，即使您通过了 null/string.Empty，它也可以正常工作。

您遇到的问题与绑定本身有关 - 没有可供绑定使用的数据上下文。将数据上下文设置为 window 本身：

<Window ... DataContext="{Binding RelativeSource={RelativeSource Self}}">

然后你的代码将工作，除了你的属性:

中的一个小错误

public string TextTest
{
    get { return this.TextTest; } << WILL CAUSE A STACK OVERFLOW
    set
    {
        this.textTest = value;
        NotifyPropertyChanged();
    }
}

此外，TextBlock 的绑定只需要是：

Text="{Binding TextTest}"

没有让 INotifyPropertyChanged 示例工作，我想从后面更新文本块

Not getting INotifyPropertyChanged example to work, I want to update text block from behind

c#

inotifypropertychanged

.net-4.5