WPF 复选框绑定 [英] WPF checkbox binding

问题描述

虽然使用复选框的 Click 事件将复选框的选中状态存储在变量中很简单，但我将如何通过数据绑定来做到这一点?我发现的所有示例都从某个数据源更新了 UI，或者将一个控件绑定到另一个控件；我想在单击复选框时更新成员变量.

While it is trivial to store a checkbox's checked state in a variable using the checkbox's Click event, how would I do it via databinding? All the examples I have found have the UI updated from some datasource, or bind one control to another; I want to update a member variable when the checkbox is clicked.

任何指针的 TIA...

TIA for any pointers...

推荐答案

为此您需要一个依赖属性:

You need a dependency property for this:

public BindingList<User> Users
{
    get { return (BindingList<User>)GetValue(UsersProperty); }
    set { SetValue(UsersProperty, value); }
}

public static readonly DependencyProperty UsersProperty =
    DependencyProperty.Register("Users", typeof(BindingList<User>), 
      typeof(OptionsDialog));

完成后，将复选框绑定到依赖项属性:

Once that is done, you bind the checkbox to the dependency property:

<CheckBox x:Name="myCheckBox"
          IsChecked="{Binding ElementName=window1, Path=CheckBoxIsChecked}" />

为此，您必须在其开始标记中命名您的 Window 或 UserControl，并在 ElementName 参数中使用该名称.

For that to work you have to name your Window or UserControl in its openning tag, and use that name in the ElementName parameter.

使用此代码，无论何时更改代码端的属性，都会更改文本框.此外，每当您选中/取消选中文本框时，依赖属性也会发生变化.

With this code, whenever you change the property on the code side, you will change the textbox. Also, whenever you check/uncheck the textbox, the Dependency Property will change too.

创建依赖属性的一种简单方法是输入代码片段 propdp，它会为您提供依赖属性的通用代码.

An easy way to create a dependency property is typing the snippet propdp, which will give you the general code for Dependency Properties.

全部代码:

XAML:

<Window x:Class="StackOverflowTests.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" x:Name="window1" Height="300" Width="300">
    <Grid>
        <StackPanel Orientation="Vertical">
            <CheckBox Margin="10"
                      x:Name="myCheckBox"
                      IsChecked="{Binding ElementName=window1, Path=IsCheckBoxChecked}">
                Bound CheckBox
            </CheckBox>
            <Label Content="{Binding ElementName=window1, Path=IsCheckBoxChecked}"
                   ContentStringFormat="Is checkbox checked? {0}" />
        </StackPanel>
    </Grid>
</Window>

C#:

using System.Windows;

namespace StackOverflowTests
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public bool IsCheckBoxChecked
        {
           get { return (bool)GetValue(IsCheckBoxCheckedProperty); }
           set { SetValue(IsCheckBoxCheckedProperty, value); }
        }

        // Using a DependencyProperty as the backing store for 
         //IsCheckBoxChecked.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IsCheckBoxCheckedProperty =
            DependencyProperty.Register("IsCheckBoxChecked", typeof(bool), 
            typeof(Window1), new UIPropertyMetadata(false));

        public Window1()
        {             
            InitializeComponent();
        }
    }
}

注意背后的唯一代码是依赖属性.标签和复选框都绑定到它.如果复选框更改，标签也会更改.

Notice how the only code behind is the Dependency Property. Both the label and the checkbox are bound to it. If the checkbox changes, the label changes too.

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