如何将 WPF TextBox 绑定到作为应用程序主窗口成员的属性
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How to bind WPF TextBox to a propperty that is the member of application main window
提问by user1688773
I have a private field
我有一个私人领域
private static Double myValue;
in the application MainWindow class. And there (in the MainWindow class) I defined a property
在应用程序 MainWindow 类中。在那里（在 MainWindow 类中）我定义了一个属性
public static Double MytValue
{
get { return myValue; }
}
In the structure of the MainWindow class I have a TextBox. I'm in need of binding it to the MytValue property. In XAML I write:
在 MainWindow 类的结构中，我有一个 TextBox。我需要将它绑定到 MytValue 属性。在 XAML 我写：
<TextBox Name="tbxMyValue" Grid.Row="1" Grid.Column="2" TextAlignment="Center"
Text="{Binding Path=MyValue}" Width="Auto" Margin="10,0,10,15" IsEnabled="True" />
But it has no effect. I see nothing in the TextBox while myValue variable has a value. Why? Please help me.
但它没有效果。我在 TextBox 中什么也看不到，而 myValue 变量有一个值。为什么？请帮我。
回答by paparazzo
I like to set the DataContext in the Window section
我喜欢在 Window 部分设置 DataContext
<Window x:Class="Gabe3a.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Gabe3a"
xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase"
xmlns:System="clr-namespace:System;assembly=mscorlib"
DataContext="{Binding RelativeSource={RelativeSource self}}"
Title="Gabriel Main Ver 3a01" Icon="faviconw.ico" Height="600" Width="800">
回答by Rachel
You need to set the DataContextbehind the Window for that binding to work
您需要DataContext在 Window 后面设置该绑定才能工作
There are two layers to an application with WPF: the UI layer and the data layer.
使用 WPF 的应用程序有两层：UI 层和数据层。
The Data layer for an application starts out as null, and you can set it using the DataContextproperty.
应用程序的数据层以 开头null，您可以使用DataContext属性设置它。
Whenever you do a basic binding in WPF, you are binding to the DataContext. So Text="{Binding Path=MyValue}"is actually saying "Get the MyValueproperty from the current DataContext".
每当您在 WPF 中进行基本绑定时，您都将绑定到DataContext. 所以Text="{Binding Path=MyValue}"实际上是在说“MyValue从当前获取财产DataContext”。
You could simply set the DataContextin your code behind:
你可以简单地DataContext在你的代码后面设置：
MyWindow.DataContext = this;
Or you can use a RelativeSourcebinding to tell WPF to get the MyValueproperty from somewhere else, such as telling it to get it from the closest Window it finds when navigating up the VisualTree:
或者您可以使用RelativeSource绑定来告诉 WPFMyValue从其他地方获取属性，例如告诉它从它在导航时找到的最近的窗口获取它VisualTree：
Text="{Binding Path=MyValue, RelativeSource={
RelativeSource AncestorType={x:Type Window}}}"
I actually have an article on my blog about the DataContextthat I'd recommend reading if you're new to WPF and the DataContext: What is this "DataContext" you speak of?
实际上，我的博客上有一篇关于DataContext如果您不熟悉 WPF 和我建议您阅读的文章DataContext：您所说的“DataContext”是什么？
回答by Erti-Chris Eelmaa
It's not how it works. Binding to static properties; {Binding Source={x:Static local:Application.MyValue}}
这不是它的工作原理。绑定到静态属性；{绑定源={x:静态本地:Application.MyValue}}
Note that your field needs to be property & public. If you want to go with your solution, you need to set DataContext as {RelativeSource Self}.
请注意，您的领域必须是财产和公共领域。如果您想使用您的解决方案，您需要将 DataContext 设置为 {RelativeSource Self}。
回答by kmatyaszek
In file MainWindow.xaml.cs in constructor add this line:
在构造函数的文件 MainWindow.xaml.cs 中添加以下行：
DataContext = this;
after InitializeComponent();
后 InitializeComponent();
