WPF学习历程2----Binding(一)

Binding基础

Eg1让数据源的类实现System.ComponentModel名称空间中的INotifyPropertyChanged接口，当Binding设置了数据源后，Binding就会自动侦听来自这个接口的PropertyChanged事件

xaml代码：

    <StackPanel>

        <TextBox x:Name="txt_Name" BorderBrush="Blue" Margin="5"></TextBox>

        <Button Content="增加" Margin="5" Click="Button_Click"></Button>

    </StackPanel>

 C#代码：

    public partial class MainWindow : Window

    {

        Student stu;

        public MainWindow()

        {

            InitializeComponent();

            stu = new Student();

 

            Binding binding= new Binding();

            binding.Source = stu;

            binding.Path = new PropertyPath("Name");

 

            BindingOperations.SetBinding(this.txt_Name, TextBox.TextProperty, binding);

        }

 

        public void Button_Click(object sender, RoutedEventArgs e)

        {

            stu.Name += "Name";

        }

    }

    class Student : INotifyPropertyChanged

    {

        public event PropertyChangedEventHandler PropertyChanged;

 

        public string name;

 

        public string Name

        {

            get { return name; }

            set

            {

                name = value;

                if (this.PropertyChanged != null)

                {

                    this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs("Name"));

                }

            }

        }

    }

 

 

其中代码可以简写，TextBox这类UI元素的基类FrameworkElement对BindingOperations.SetBinding(……)方法进行了封装，封装的结果也叫SetBinding

C#代码：

    public partial class MainWindow : Window

    {

        Student stu;

        public MainWindow()

        {

            InitializeComponent();

            this.txt_Name.SetBinding(TextBox.TextProperty, new Binding("Name") { Source = stu = new Student() });

        }

        public void Button_Click(object sender, RoutedEventArgs e)

        {

            stu.Name += "Name";

        }

    }

建立模型

                                  

Binding的源与路径

方法一：

    <StackPanel>

        <TextBox x:Name="txt_Name" Text="{ Binding Path=Value, ElementName=slider1}" BorderBrush="Blue" Margin="5"></TextBox>

        <Slider x:Name="slider1" Maximum="100" Minimum="0" Margin="5"></Slider>

    </StackPanel>

方法二：

C#代码

            Binding binding = new Binding() { Path = new PropertyPath("Value"), Source = this.slider1 };

            this.txt_Name.SetBinding(TextBox.TextProperty, binding);

 

或者

            Binding binding = new Binding("Value") { Source=this.slider1};

            this.txt_Name.SetBinding(TextBox.TextProperty, binding);

                                                             

Binding多路径

    <StackPanel>

        <TextBox x:Name="textbox1" BorderBrush="Blue" Margin="5"></TextBox>

        <TextBlock Text="文本的长度" Margin="5"></TextBlock><TextBox x:Name="showlength" Text="{Binding Path=Text.Length,ElementName=textbox1,Mode=OneWay}" BorderBrush="Blue" Margin="5"></TextBox>

        <TextBlock Text="取得第3个文本"></TextBlock><TextBox x:Name="showIndex" Text="{Binding Path=Text[2],ElementName=textbox1,Mode=OneWay}" BorderBrush="Blue" Margin="5"></TextBox>

    </StackPanel>

 

或者

            this.showlength.SetBinding(TextBox.TextProperty, new Binding("Text.Length") { Source = this.textbox1, Mode = BindingMode.OneWay });

            this.showIndex.SetBinding(TextBox.TextProperty, new Binding("Text[2]") { Source = this.textbox1, Mode = BindingMode.OneWay });

                                                               

当使用一个集合或者Dadaview作为Binding源时

            List<string> stringList = new List<string>() { "iPhone", "Lumia900", "HTC" };

            this.textbox1.SetBinding(TextBox.TextProperty, new Binding("/") { Source = stringList });

            this.textbox2.SetBinding(TextBox.TextProperty, new Binding("/Length") { Source = stringList, Mode = BindingMode.OneWay });

            this.textbox3.SetBinding(TextBox.TextProperty, new Binding("/[2]") { Source = stringList, Mode = BindingMode.OneWay });

                                                                 

“没有Path”的Binding

    <StackPanel>

        <StackPanel.Resources>

            <sys:String x:Key="myString">

                iPhone Lumia

                HTC

            </sys:String>

        </StackPanel.Resources>

        <TextBlock x:Name="textblock1" TextWrapping="Wrap" Text="{Binding Path=.,Source={StaticResource ResourceKey=myString}}" FontSize="16" Margin="5"></TextBlock>

    </StackPanel>

 

或者

            string myString="iphone,Lumia900,HTC";

            this.textblock1.SetBinding(TextBlock.TextProperty, new Binding(".") { Source = myString });