C# 将类中的属性直接绑定到 XAML

Binding a property from a class to XAML directly

提问by djangojazz

I was curious as I was learning more on binding with WPF do you HAVE TO set the data context to simply set the {binding path=} of a single property? I was just curious as I was learning from the MVVM example of code behind and it appears I have a situation I want to bind to something not in the data context of the ViewModel and I would prefer an intermediary class over code behind to reference in a binding. So could I have yet another class I reference for either a second datacontext or something similar? Or could I set a resource key and reference the class somehow? I ultimately want to access a property in a separate class if possible.

我很好奇，因为我正在学习有关 WPF 绑定的更多信息，您是否必须设置数据上下文以简单地设置单个属性的 {binding path=}？我只是好奇，因为我正在从背后代码的 MVVM 示例中学习，看来我有一种情况我想绑定到不在 ViewModel 的数据上下文中的东西，我更喜欢中间类而不是代码背后的引用捆绑。那么我可以为第二个数据上下文或类似的东西引用另一个类吗？或者我可以设置一个资源键并以某种方式引用该类吗？如果可能的话，我最终想访问一个单独的类中的属性。

EG:

例如：

<Window x:Class="WPFTestBinding.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:da="clr-namespace:WPFTestBinding.DataAccess"
        xmlns:main="clr-namespace:WPFTestBinding"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <StackPanel>
            <Label Content="Here we go: "/>
            <TextBox x:Name="testtext" />
            <Label Height="50" />
            <!-- CODE BELOW WILL NOT WORK -->
            <TextBox Text="{Binding Path=TestID}" x:Name="testtext2" />
        </StackPanel>
    </Grid>
</Window>

I know I can set the value of a TextBox in code behind and it works in the example of a property but it will not for the binding. Is there a way to do simple binding on the fly for properties from classes? I have not found a simple example that does this and I was searching online and while learning binding most examples are either very intense sets of settings data contexts or very simple static resource examples. I was just curious if you could use the {Binding Path=} and extend some other property on the fly to just get the code in the class.

我知道我可以在后面的代码中设置 TextBox 的值，它在属性示例中有效，但不适用于绑定。有没有办法动态地对类的属性进行简单的绑定？我还没有找到一个简单的例子，我在网上搜索，在学习绑定时，大多数例子要么是非常密集的设置数据上下文集，要么是非常简单的静态资源示例。我只是好奇您是否可以使用 {Binding Path=} 并动态扩展一些其他属性来获取类中的代码。

Rest of code is pretty simple:

其余代码非常简单：

namespace WPFTestBinding.DataAccess
{
    class Test
    {
        public string TestID { get { return "This is my test"; } }
    }
}

 public partial class MainWindow : Window
    {    
        public MainWindow()
        {
           InitializeComponent();

           DataAccess.Test t = new Test();

           testtext.Text = t.TestID;  // code behind works easily
         }
    }

采纳答案by kusi581

You can set the DataContext in Xaml like this:

您可以像这样在 Xaml 中设置 DataContext：

<Window xmlns:da="clr-namespace:WPFTestBinding.DataAccess">
    <Window.DataContext>
        <da:Test/>
    <Window.DataContext>

    <TextBox Text="{Binding TestID}"/>
</Window>

回答by Sergii Vashchyshchuk

The data context is not set. The DataBinding doesn't know where to take TestID from. Here is correct code behind:

未设置数据上下文。DataBinding 不知道从哪里获取 TestID。下面是正确的代码：

namespace WPFTestBinding.DataAccess
{
    class Test
    {
        public string TestID { get { return "This is my test"; } }
    }
}

public partial class MainWindow : Window
{    
    public MainWindow()
    {
       InitializeComponent();
       DataAccess.Test t = new Test();

       DataContext = t;           
    }
}

回答by Harsh Baid

Some points to note:

需要注意的几点：

• The property TestIDyou are trying to bind is read-only, as it only has get-accessor. Therefore, Binding should be OneWayonly.
• Assigning the DataContext: You can assign the instance holding your model such MainViewModel with ICollection<BaseViewModel> property (which would be having all the derived instances in the collection) or directly the model itself (as in your case). As I have done in code below.

• TestID您尝试绑定的属性是只读的，因为它只有 get-accessor。因此，Binding 应该是OneWay唯一的。
• 分配 DataContext：您可以分配包含模型的实例，例如带有 ICollection<BaseViewModel> 属性的 MainViewModel（它将包含集合中的所有派生实例）或直接分配模型本身（如您的情况）。正如我在下面的代码中所做的那样。

Code

代码

namespace WPFTestBinding.DataAccess
{
    class Test
    {
        public string TestID { get { return "This is my test"; } }
    }
}

public partial class MainWindow : Window
{    
    public MainWindow()
    {
       InitializeComponent();

       DataAccess.Test testInstance = new Test();
       this.DataContext = testInstance;
    }
}

XAML

XAML

<TextBox Text="{Binding Path=TestID, Mode=OneWay}" x:Name="txtTestID" />

For more refer:

更多请参考：

• MSDN - Data Binding Overview
• MSDN - WPF BindingMode
• Code Project - DataContext-in-WPF
• SO - What is DataContext for?
• SO - Difference between Datacontext and ItemSource

• MSDN - 数据绑定概述
• MSDN - WPF 绑定模式
• 代码项目 - DataContext-in-WPF
• SO - DataContext 有什么用？
• SO - Datacontext 和 ItemSource 之间的区别

回答by M Komaei

1 - You have to fill the Prop beforeInitializeComponent(); in .cs class.

1 - 您必须在InitializeComponent()之前填充 Prop ；在 .cs 类中。

2 - use this in Window tag : DataContext="{Binding RelativeSource={RelativeSource Self}}"

2 - 在 Window 标签中使用它：DataContext="{Binding RelativeSource={RelativeSource Self}}"

3 - Label tag : Label Content="{Binding Currency}"

3 - 标签标签：标签内容="{绑定货币}"