写入输出消息(C#=> TextBox)

Question

我有TextBox:

 <TextBox  DockPanel.Dock="Bottom"               
           FontFamily="Consolas"
           Text="{Binding Path=Output}"
           VerticalScrollBarVisibility="Visible"
           HorizontalScrollBarVisibility="Auto"
           AcceptsReturn="True"
           AcceptsTab="True" /> 

在这个TextBox内部我想发送一些/添加消息:

public string Output { get; set; }
public void WriteToOutput(string message)
{
 Output += DateTime.Now.ToString("dd.MM HH:mm:ss") + " " + message + Environment.NewLine;
}     

public void LoadExcelFile()
{
  WriteToOutput("Start....")
  //SOME CODE
  WriteToOutput("End....")
}

输出应如下所示:

Start...
End...

但它没有显示在TextBox中的文本.是什么原因？

更新:我的MainViewModel.cs:

[AddINotifyPropertyChangedInterface]
public class MainViewModel
{
....
}

我正在使用 PropertyChanged.Fody

Answer 1

你错过了INotifyPropertyChanged实施.

一个工作的例子:

using System.ComponentModel;

public partial class MainWindow : Window, INotifyPropertyChanged
{
    private string output;
    public string Output
    {
        get { return output; }
        set
        {
            output = value;
            OnPropertyChanged(); // notify the GUI that something has changed
        }
    }

    public MainWindow()
    {
        this.DataContext = this;
        InitializeComponent();
        this.Loaded += MainWindow_Loaded;
    }

    private void MainWindow_Loaded(object sender, RoutedEventArgs e)
    {
        Output = "Hallo";
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
    {
        if (PropertyChanged != null) {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName: propertyName));
        }
    }
}

XAML代码如下所示:

<TextBox Text="{Binding Output}"/>

如您所见,只要Output属性发生更改,PropertyChanged就会调用该事件.绑定到该属性的每个GUI元素都将知道某些内容已更改.

注意:[CallerMemberName]自动获取调用方法的属性的名称.如果您不想使用它,请将其删除.但是,您必须将OnPropertyChanged呼叫更改为OnPropertyChanged("Output");.