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我在 MainWindow.xaml 中手动绑定了TextBlock

<TextBlock Name="TestPrice"
                           Height="30"
                           HorizontalAlignment="Stretch"
                           VerticalAlignment="Stretch"
                           Text="{Binding Path=
                           ScreenMarketLogger, Mode=Default, UpdateSourceTrigger=PropertyChanged}"/>

在MainWindow.xaml.cs我用属性定义类：

public class ScreenLoggerBind : INotifyPropertyChanged
        {
            public event PropertyChangedEventHandler PropertyChanged;


            private string _ScreenMarketLogger;
            public string ScreenMarketLogger
            {
                get
                {
                    return _ScreenMarketLogger;
                }
                set
                {
                    _ScreenMarketLogger = value;
                    OnPropertyChanged("ScreenMarketLogger");
                }
            }

            private string _CurrentPrice;
            public string CurrentPrice
            {
                get
                {
                    return _CurrentPrice;
                }
                set
                {
                    _CurrentPrice = value;
                    OnPropertyChanged("CurrentPrice");
                }
            }

            private void OnPropertyChanged(string name)
            {
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
            }

            public ScreenLoggerBind()
            {
                this.ScreenMarketLogger = "\r\n begin \r\n";
            }
        }

我有另一个类（实际上这是单独的文件），我在其中定义ScreenLoggerBind类的构造函数。

class ExternalClass
{
...
ScreenLoggerBind ScreenLogger = new ScreenLoggerBind();
...
}

现在我将DataContext转移到这个类中，如下所示：

 public void Init(MainWindow mw)
        {
            mw.TestPrice.DataContext = ScreenLogger;
        }

并像这样在mainWindow方法中的MainWindow.xaml.cs中调用此函数

ExternalClass ext = new ExternalClass()     
public MainWindow()
    {
        InitializeComponent();
        this.DataContext = this;
        ext.Init(this);
    }

如果我为变量ScreenLogger.ScreenMarketLogger分配一个值，我会在主 WPF 表单上看到结果。在这里一切正常。

现在提问。如果我在MainWindow.xaml.cs中动态创建组件，例如：

    Label lbl_Price = new Label();
    lbl_Price.Name = string.Format("lbl_Price_{0}{1}", i.ToString(), cell.ToString());
    Binding lbl_PriceBinding = new Binding("Content");
    lbl_PriceBinding.Source = ScreenLogger.CurrentPrice;
    lbl_PriceBinding.Mode = BindingMode.Default;
    lbl_PriceBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
    lbl_Price.SetBinding(Label.ContentProperty, lbl_PriceBinding);
....

并在外部类ExternalClass.cs中定义 DataContext 

 public void Init(MainWindow mw)
        {
            mw.TestPrice.DataContext = ScreenLogger;
 foreach (Label lbl in mw.ChainGrid.Children.OfType<System.Windows.Controls.Label>())
            {
                if (lbl.Name == "lbl_XName_Price_00")
                {
 lbl.DataContext = ScreenLogger;
                }
            }
        }

这是行不通的！我看到在主窗体上动态创建了标签。但是，如果我为ScreenLogger.CurrentPrice变量赋值，我看不到任何变化。

为什么？我在哪里犯错了？

4

1 回答 1

2

尝试执行以下操作：

Binding lbl_PriceBinding = new Binding("CurrentPrice");
lbl_PriceBinding.Source = ScreenLogger;
lbl_PriceBinding.Mode = BindingMode.OneWay;

您必须在Binding构造函数中提供源属性的路径。在您的情况下，源是ScreenLogger，相对于它的路径是CurrentPrice.

于 2019-10-07T11:05:28.110 回答