Silverlight MVVM

最新推荐文章于 2019-07-27 05:22:11 发布

原创最新推荐文章于 2019-07-27 05:22:11 发布 · 490 阅读

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CC 4.0 BY-SA版权

文章标签：

#.NET #silverlight

本文介绍了Microsoft Prism框架中NotificationObject类的使用方法，包括属性更改通知机制，并展示了如何通过DelegateCommand实现命令功能。此外，还提供了XAML与C#结合使用的示例，演示了如何在UI触发事件时执行特定命令。

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通知属性修改

using System;
using System.ComponentModel;
using System.Linq.Expressions;
using System.Runtime.Serialization;

namespace Microsoft.Practices.Prism.ViewModel
{
    [DataContract]
    public abstract class NotificationObject : INotifyPropertyChanged
    {
        protected NotificationObject();

        public event PropertyChangedEventHandler PropertyChanged;

        protected void RaisePropertyChanged<T>(Expression<Func<T>> propertyExpression);
        protected void RaisePropertyChanged(params string[] propertyNames);
        protected virtual void RaisePropertyChanged(string propertyName);
    }
}

Command 注册类

using System;

namespace Microsoft.Practices.Prism.Commands
{
    public class DelegateCommand<T> : DelegateCommandBase
    {
        public DelegateCommand(Action<T> executeMethod);
        public DelegateCommand(Action<T> executeMethod, Func<T, bool> canExecuteMethod);


        public bool CanExecute(T parameter);
        public void Execute(T parameter);
    }
}

添加触发事件

添加一个触发事件类

using System;
using System.Net;
using System.Reflection;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Interactivity;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace DTO.SL
{
    /// <summary>
    /// Trigger触发的事件类
    /// </summary>
    public class ExecuteCommandAction : TriggerAction<FrameworkElement>
    {
        public static readonly DependencyProperty CommandNameProperty =
            DependencyProperty.Register("CommandName", typeof(string), typeof(ExecuteCommandAction), null);

        public string CommandName
        {
            get { return (string)GetValue(CommandNameProperty); }
            set { SetValue(CommandNameProperty, value); }
        }

        public static readonly DependencyProperty CommandParameterProperty =
            DependencyProperty.Register("CommandParameter", typeof(object), typeof(ExecuteCommandAction), null);

        public object CommandParameter
        {
            get { return GetValue(CommandParameterProperty); }
            set { SetValue(CommandParameterProperty, value); }
        }

        private static bool IsCommandProperty(PropertyInfo property)
        {
            return typeof(ICommand).IsAssignableFrom(property.PropertyType);
        }

        /// <summary>
        /// 重写Invoke方法
        /// </summary>
        /// <param name="parameter"></param>
        protected override void Invoke(object parameter)
        {
            if (AssociatedObject == null)
            {
                return;
            }

            ICommand command = null;
            var dataContext = AssociatedObject.DataContext;
            foreach (var item in dataContext.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance))
            {
                if (IsCommandProperty(item) && string.Equals(item.Name, CommandName, StringComparison.Ordinal))
                {
                    command = (ICommand)item.GetValue(dataContext, null);
                }
            }
            if ((command != null) && command.CanExecute(CommandParameter))
            {
                command.Execute(CommandParameter);
            }
        }
    }
}

Xaml代码

       xmlns:Custom="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
        xmlns:myConvert="clr-namespace:DTO.SL;assembly=DTO.SL"
      

    <Button Width="100" Height="50" Content="大" >
                <Custom:Interaction.Triggers>
                    <Custom:EventTrigger EventName="Click">
                        <myConvert:ExecuteCommandAction CommandName="MaxCommand"></myConvert:ExecuteCommandAction>
                    </Custom:EventTrigger>
                </Custom:Interaction.Triggers>
            </Button>

CS代码

using Microsoft.Practices.Prism.ViewModel;
using Microsoft.Practices.Prism.Commands;
 
       private ICommand maxCommand;
        public ICommand MaxCommand
        {
            get { return maxCommand; }
            set { maxCommand = value; }
        }

     MaxCommand = new DelegateCommand(() =>
                {
                    //事件内容
                });