silverlight中写Com组件 实现打开本地文件功能

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.IO;
using System.Diagnostics;


namespace OpenFileCom
{
    /// <summary>
    /// 事件接口
    /// </summary>
    [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    public interface IComEvents
    {
        /// <summary>
        /// 定义要暴露的事件
        /// </summary>
        void OnHelloBegin(object sender, EventArgs e);
    }

    public class HelloEvents : EventArgs
    { }

    /// <summary>
    /// 自定义定义委托
    /// </summary>
    public delegate void Comdel(object sender, EventArgs e);

    [ComVisible(true)]
    [ComSourceInterfaces(typeof(IComEvents))]
    public class IMDCOMTEST
    {
        public string Hello()
        {
            if (OnHelloBegin != null)
                OnHelloBegin(this, new HelloEvents());
            return "asdasdasd";
        }
        public string OpenFile(string _path)
        {

            // var extensionName = Path.GetExtension(_path);
            try
            {
                if (!File.Exists(_path))
                    throw new FileNotFoundException();
                Process p = new Process();
                p.StartInfo.FileName = "cmd.exe";           //設定程序名
                p.StartInfo.Arguments = string.Format("/c \"{0}\"", _path);    //設定程式執行參數
                p.StartInfo.UseShellExecute = false;        //關閉Shell的使用
                p.StartInfo.RedirectStandardInput = true;   //重定向標準輸入
                p.StartInfo.RedirectStandardOutput = true;  //重定向標準輸出
                p.StartInfo.RedirectStandardError = true;   //重定向錯誤輸出
                p.StartInfo.CreateNoWindow = true;          //設置不顯示窗口
                return p.Start() ? "" : "打开失败";   //啟動                 
            }
            catch (Exception ex) { return ex.Message; }
        }

        /// <summary>
        /// 实现事件接口
        /// </summary>
        public event Comdel OnHelloBegin;
    }
}