WPF之绑定

绑定的几种方式

1 元素绑定

    <Grid>
        <StackPanel >
            <TextBox x:Name="t1" HorizontalAlignment="Left" Margin="35,26,0,0" TextWrapping="Wrap"   Height="25" Width="266"/>
             <!--元素绑定：绑定Name值为t1的元素，Path=Text表示将这个元素值的Text值赋给当前元素的Text属性-->
            <TextBox Text="{Binding Text, ElementName=t1}" HorizontalAlignment="Left" Margin="35,71,0,0"   VerticalAlignment="Top" Height="26" Width="266"/>
          
        </StackPanel>
    </Grid>

2 RelativeSource绑定

3 绑定后台业务代码

比如后台有如下类：

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            //注意要在这里将数据添加到上下文中
            this.DataContext = new TestModel();
        }

    }
    public class TestModel
    {
        public TestModel()
        {
            Name = "Hello";
        }
        private string name;

        public string Name { get => name; set => name = value; }
    }
}

xaml中绑定：

<Window x:Class="MyWpf.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
        mc:Ignorable="d"  
        Title="MainWindow" Height="296.042" Width="347.333"  > 
    <Grid>
        <StackPanel > 
            <TextBlock Text="{Binding Name,FallbackValue='error'}" HorizontalAlignment="Left" Margin="35,71,0,0" 
         VerticalAlignment="Top" Height="26" Width="266"/> 
        </StackPanel>
    </Grid>
</Window>

我们还可以换一种方式写，用强类型视图的方式来写，直接在xaml文件中指定当前上下文用什么模型：

<Window x:Class="MyWpf.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
        mc:Ignorable="d" 
    xmlns:local="clr-namespace:MyWpf"
        Title="MainWindow" Height="296.042" Width="347.333"  >
    <Window.DataContext>
        <!--之所在这里能直接这样写，是因为前面属性中引入了这个类的命名空间，  xmlns:local="clr-namespace:MyWpf" -->
        <local:TestModel></local:TestModel>
    </Window.DataContext>
    <Grid>
        <StackPanel >

            <TextBlock Text="{Binding Name,FallbackValue='error'}" HorizontalAlignment="Left" Margin="35,71,0,0"   
   VerticalAlignment="Top" Height="26" Width="266"/>

        </StackPanel>
    </Grid>
</Window>

这样写的话，在Binding中就会有提示有哪些属性是可以被绑定的。

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