学步园

    WPF中界面全部都用XAML显示相应的控件，确切来说，WPF是想让WINFORM界面的开发像网页开发一样。在Winform中只要控件名.属性=设置的属性值，那么在WPF中不用再这么麻烦了。这里就说说数据绑定的用法吧。界面上有很多要显示后台数据的控件，后台数据改变了，那么如何让界面数据也实时发生改变呢？这就用到绑定。
使用数据绑定有这么几个步骤：
第一步，有一个实现了INotifyPropertyChanged接口的类；
第二步，页面显示的数据模型类，这个类要继承自第一步的实现了INotifyPropertyChanged接口的类；
第三步，界面的后台类要声明数据模型类，并且要绑定
 this.DataContext = this.数据模型类对象;//绑定，这句才实现了绑定
 第四步，界面控件的相应属性和模型类对象绑定，如下，
 <TextBox  Text="{Binding 数据模型类相应属性}" />
 看代码：
 1、实现接口的类

   /// <summary>
    /// NotiyObject必须实现INotifyPropertyChanged接口
    /// </summary>
    public abstract class NotifyProperty : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public void OnChangedProperties(string propertyName)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

2、页面显示的数据模型类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Windows;

namespace TestAttributeDependency.BindData
{
    public class MainFormDataModel : NotifyProperty
    {
        private string textBoxContent = string.Empty;

        private Visibility btnShowContent = Visibility.Visible;

        private Visibility btnClearContent = Visibility.Collapsed;

        /// <summary>
        /// 文本框内显示的内容
        /// </summary>
        public string TextBoxContent
        {
            get
            {
                return this.textBoxContent;
            }

            set
            {
                this.textBoxContent = value;

                //必须调用该事件才能完成前台相应绑定内容的改变
                //而且propertyName最好和绑定的对象名称一致
                this.OnChangedProperties(@"TextBoxContent");
            }
        }
        /// <summary>
        /// 显示内容按钮是否显示
        /// </summary>
        public Visibility BtnShowContent
        {
            get
            {
                return this.btnShowContent;
            }

            set
            {
                this.btnShowContent = value;

                this.OnChangedProperties(@"BtnShowContent");
            }
        }

        /// <summary>
        /// 清空内容按钮是否显示
        /// </summary>
        public Visibility BtnClearContent
        {
            get 
            { 
                return btnClearContent;
            }
            set 
            {
                btnClearContent = value;

                this.OnChangedProperties(@"BtnClearContent");
            }
        }
    }
}

3、界面的后台声明数据模型对象

using System.Windows;
using TestAttributeDependency.BindData;

namespace TestAttributeDependency
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        /// <summary>
        /// 需要绑定的对象
        /// </summary>
        internal MainFormDataModel mainFormDataModel = new MainFormDataModel();

        /// <summary>
        /// 构造函数
        /// </summary>
        public MainWindow()
        {
            InitializeComponent();

            this.DataContext = this.mainFormDataModel;//绑定，这句才实现了绑定

            InitializeCutom();
        }
        /// <summary>
        /// 自定义初始化
        /// </summary>
        void InitializeCutom()
        {
            mainFormDataModel.TextBoxContent = string.Empty;

            mainFormDataModel.BtnShowContent = System.Windows.Visibility.Visible;

            mainFormDataModel.BtnClearContent = System.Windows.Visibility.Collapsed;
        }

        /// <summary>
        /// 显示内容按钮点击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnShowContent_Click(object sender, RoutedEventArgs e)
        {
            mainFormDataModel.TextBoxContent = @"哈哈，按钮被点击了！";

            //通过Visibility控制控件的显示
            mainFormDataModel.BtnShowContent = Visibility.Collapsed;

            mainFormDataModel.BtnClearContent = Visibility.Visible;
        }
        /// <summary>
        /// 清空内容按钮点击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnClearContent_Click(object sender, RoutedEventArgs e)
        {
            if (this.txtShowContent.Text.Length > 0)
            {
                this.txtShowContent.Text = string.Empty;
            }

            mainFormDataModel.BtnShowContent = Visibility.Visible;

            mainFormDataModel.BtnClearContent = Visibility.Collapsed;
        }
    }
}

4、前台界面的写法

<Window x:Class="TestAttributeDependency.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TextBox Height="23" HorizontalAlignment="Left" Margin="12,70,0,0" Name="txtShowContent" VerticalAlignment="Top" Width="185" Text="{Binding TextBoxContent}" />
        <Button Content="显示内容" Height="23" HorizontalAlignment="Left" Margin="215,69,0,0" Name="btnShowContent" VerticalAlignment="Top" Width="75" Click="btnShowContent_Click" Visibility="{Binding BtnShowContent}" />
        <Button Content="清空内容" Height="23" HorizontalAlignment="Right" Margin="0,70,132,0" Name="btnClearContent" VerticalAlignment="Top" Width="75" Click="btnClearContent_Click" Visibility="{Binding BtnClearContent}" />
    </Grid>
</Window>

完成后效果如下：

点击“显示内容”按钮，TextBox中显示内容，并且“显示内容”按钮隐藏，"清空内容"按钮显示；点击"清空内容"按钮则相反。

代码下载：http://download.csdn.net/detail/yysyangyangyangshan/4487055