C#WPF - 如何始终从文本框中获取当前文本?

Esa*_*sad 4 c# wpf xaml mvvm

我在FileWindow.xaml中有一个TextBox:

<TextBox x:Name="textBox" HorizontalAlignment="Left" Height="23" Margin="233,230,0,0" TextWrapping="Wrap" Text="{Binding FileName}" VerticalAlignment="Top" Width="120"/>
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在ViewModel.cs中:

public String FileName
{
    get { return _model.filename; }
    set
    {
        if (value != _model.filename)
        {
            _model.filename = value;
            OnPropertyChanged();
        }
    }
}
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在Model.cs中:

private String _filename = "example.txt";
public String filename { get { return _filename; } set { _filename = value; } }
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我希望每次输入TextBox时,Model.cs中的_filename都会更新.
TextBox中的默认文本是example.txt,但如果我更改它,Model.cs中的_filename不会更改.我究竟做错了什么?

mm8*_*mm8 5

尝试UpdateSourceTrigger将绑定的属性设置为PropertyChanged:

Text="{Binding FileName, UpdateSourceTrigger=PropertyChanged}" 
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