WPF Binding学习

Posted 2020-10-21 莫问今朝

转自;http://blog.csdn.net/lisenyang/article/details/18312199

1.控件与控件间的双向绑定

WPF还支持控件作为数据源,

 <TextBox Name="txt_Source" Width="120" HorizontalAlignment="Left"></TextBox>
 <TextBox Text="{Binding ElementName=txt_Source,Path=Text}" Name="txt_Target" Width="120" HorizontalAlignment="Left">

上面代码就可以实现控件之间的双向绑定,我们发现我们的绑定数据源不是Source,而是ElementName.

当然我们也可以使用代码来实现

 Binding binding = new Binding("Text") { Source = this.txt_Source };
            this.txt_Target.SetBinding(TextBox.TextProperty, binding);

使用代码绑定我们依然使用的Source来绑定数据源

2.多级路径

WPF支持多级路径,也就是我们通俗的说“点”下去。

我们改下上面的代码

 Binding binding = new Binding("Text.Length") { Source =this.txt_Source,Mode = BindingMode.OneWay };
 this.txt_Target.SetBinding(TextBox.TextProperty, binding);

注意:因为源数据和目标数据无法做到匹配,所以无法双向绑定。

我们可以看到我们绑定的数据是Text属性中的Length属性,这就是我们所谓的多级路径.

3.索引绑定

我们知道，集合类型是索引器(Indexer)又称为带参属性。既然是属性，索引器也能作为Path来使用,比如我们想让一个TextBox显示另外一个TextBox的第1个字符

 Binding binding = new Binding("Text[1]") { Source =this.txt_Source,Mode = BindingMode.OneWay };
            this.txt_Target.SetBinding(TextBox.TextProperty, binding);

4.集合绑定

当使用一个集合或者DataView做为数据源时，如果我们想把它默认的元素做为数据源使用，则需要使用下面的语法:

  List<string> list = new List<string>() { "狗娃","狗剩2"};
  txt_List1.SetBinding(TextBox.TextProperty, new Binding("/") { Source = list, Mode = BindingMode.OneTime });
  txt_List2.SetBinding(TextBox.TextProperty, new Binding("/[1]") { Source = list,Mode = BindingMode.OneTime });
  txt_List3.SetBinding(TextBox.TextProperty, new Binding("/Length") { Source = list, Mode = BindingMode.OneTime });

效果如下

如果想要绑定绑定第二个元素,则直接使用"点"即可

  List<string> list = new List<string>() { "狗娃","狗剩2"};
  txt_List1.SetBinding(TextBox.TextProperty, new Binding("[1]") { Source = list, Mode = BindingMode.OneTime });
  txt_List2.SetBinding(TextBox.TextProperty, new Binding("[1].[1]") { Source = list,Mode = BindingMode.OneTime });
  txt_List3.SetBinding(TextBox.TextProperty, new Binding("[1].Length") { Source = list, Mode = BindingMode.OneTime });

如果想把子集集合中元素作为Path,可以使用多级斜线方法(一路"斜线"下去);

我们创建一个省市区关系的类型

 public  class Province
    {
        public string Name { get; set; }
        public IList<City> Citys { get; set; }
    }
    public class City
    {
        public string Name { get; set; }
        public IList<District> Districts { get; set; }
    }
    public class District
    {
        public string Name { get; set; }
    }

然后我们使用多级斜线进行绑定

  List<Province> list = new List<Province>()
            {
                new Province
                {
                    Name ="河北",
                    Citys = new List<City>
                    {
                        new City
                        {
                            Name = "邯郸",
                            Districts = new List<District>{ new District { Name="邯山区"} }
                        } } } };
  txt_List1.SetBinding(TextBox.TextProperty, new Binding("/Name") { Source = list, Mode = BindingMode.OneTime });
  txt_List2.SetBinding(TextBox.TextProperty, new Binding("/Citys/Name") { Source = list, Mode = BindingMode.OneTime });
  txt_List3.SetBinding(TextBox.TextProperty, new Binding("/Citys/Districts/Name") { Source = list, Mode = BindingMode.OneTime });

当然也可以使用多级"点"进行绑定

 txt_List1.SetBinding(TextBox.TextProperty, new Binding("[0].Name") { Source = list, Mode = BindingMode.OneTime });
 txt_List2.SetBinding(TextBox.TextProperty, new Binding("[0].Citys[0].Name") { Source = list, Mode = BindingMode.OneTime });
 txt_List3.SetBinding(TextBox.TextProperty, new Binding("[0].Citys[0].Districts[0].Name") { Source = list, Mode = BindingMode.OneTime });