学步园

3)视图模型层DynamicDataViewModel .cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using MAppStructure.Datasource;
using System.ComponentModel;
using System.Collections.Generic;
using MEntities;
namespace MAppStructure.ViewModel
{
    /// <summary>
    /// 视图模型层，注意必须实现INotifyPropertyChanged接口，这样VM层才能绑定。
    /// ViewModel可以做一个基类，这个基类主要是实现INotifyPropertyChanged接口
    /// 和你需要的一些公共方法，这里为了简单些，就没有做基类了.
    /// </summary>
    public class DynamicDataViewModel : INotifyPropertyChanged
    {
        /// <summary>
        /// 视图模型层主要采用的模型层服务实例，注意
        /// 可以调用多个模型层得服务实例，这里是演示，所以只做了一个。
        /// </summary>
        private DynamicDataSource theS;
        public DynamicDataViewModel()
        {
            theS = new DynamicDataSource();
            //初始化并注册命令.
            Commands = new Dictionary<string, MyCommand>();
            Commands.Add("Button1Command", new MyCommand(OnButtonCommand));
        }
        private void OnButtonCommand(object parameter)
        {
            LoadData();
            MessageBox.Show("ok");
        }
       
        /// <summary>
        ///命令字典集合，这样做的好处一是可以减少定义命令的硬代码，同时提供了一种动
        ///态命令的可能性，并有利于扩展.
        /// </summary>
        public Dictionary<string, MyCommand> Commands
        {
            get;
            private set;
        }
        private List<DynamicDataRow> _DataSource;
        public List<DynamicDataRow> DataSource
        {
            get
            {
                return _DataSource;
            }
            private set
            {
                _DataSource = value;
                RaisePropertyChanged("DataSource");
              
            }
        }
        private DynamicDataTable _DataTable;
        /// <summary>
        /// 获取来的动态数据表.
        /// </summary>
        public DynamicDataTable DataTable
        {
            get
            {
                return _DataTable;
            }
            private set
            {
                _DataTable = value;
                RaisePropertyChanged("DataTable");

            }
        }
        /// <summary>
        /// 数据加载.
        /// </summary>
        private void LoadData()
        {
            theS.GetDynamicDataTable("select * from EmployeeInfo ", op =>
                {
                    if (op.HasError == false)
                    {
                        DataSource = op.Value.Rows;
                        DataTable = op.Value;
                    }
                    else
                    {
                        MessageBox.Show(op.ErrorMsg);
                    }
                }, null);
        }
        public event PropertyChangedEventHandler PropertyChanged;
        protected void RaisePropertyChanged(string propertyName)
        {
            var handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
    /// <summary>
    /// 自己的命令类，主要为了命令的绑定.这里是典型的命令模式，命令的接收者是本VM.不过这里的
    /// 命令接收者并没有作为命令的成员，而是采用委托方式，在这种情况下更为便利。
    /// </summary>
    public class MyCommand : ICommand
    {
        public bool CanExecute(object parameter)
        {
            return true;
        }
        private Action<object> _action;
        public MyCommand(Action<object> Action)
        {
            this._action = Action;
        }
        public event EventHandler CanExecuteChanged;

        public void Execute(object parameter)
        {
            if (_action != null)
            {
                _action(parameter);
            }
        }
    }
}
这里大家注意的是，我的命令采用的不是一般的定义方式，而是采用字典集合的方式进行，好处上面讲了，请大家注意页面的绑定方式。