[转] 从 dll 程序集中动态加载窗体

using System;
using System.Drawing;
using System.IO;
using System.Reflection;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace WindowsFormTest
{
    /// <summary>
    /// Form1 的摘要说明。
    /// </summary>
    public class FrmMain : System.Windows.Forms.Form
    {
        private int formNum;
        private ArrayList formTypes = new ArrayList();
        private ArrayList formObjects = new ArrayList();

        private System.Windows.Forms.MainMenu mnuMain;
        private System.Windows.Forms.MenuItem mnuItmRun;
        private System.Windows.Forms.MenuItem mnuItemWindow;
        private System.Windows.Forms.MenuItem mnuItmHelp;
        private System.Windows.Forms.MenuItem mnuItmCascade;
        private System.Windows.Forms.MenuItem mnuItmTileHorizontal;
        private System.Windows.Forms.MenuItem mnuItmTileVertical;
        private System.Windows.Forms.MenuItem menuItem1;
        private System.Windows.Forms.MenuItem mnuItmAbout;
        private System.Windows.Forms.StatusBar staBarMain;
        private System.Windows.Forms.StatusBarPanel pnlInfo;
        private System.Windows.Forms.StatusBarPanel pnlNum;
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.Container components = null;

        public FrmMain()
        {
            //
            // Windows 窗体设计器支持所必需的
            //
            InitializeComponent();

            //
            // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
            //
        }

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null) 
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        Windows 窗体设计器生成的代码

        private void FrmMain_Load(object sender, System.EventArgs e)
        {
            Assembly assembly = null;
            string windowsPath = Path.Combine(Application.StartupPath, "Windows");

            foreach (string dllFile in Directory.GetFiles(windowsPath, "*.dll"))
            {
                assembly = Assembly.LoadFile(dllFile);
                Type[] types = assembly.GetTypes();
                
                foreach (Type t in types)
                {
                    if (t.BaseType == typeof(Form))
                    {
                        this.formTypes.Add(t);
                        MenuItem item = this.mnuItmRun.MenuItems.Add(t.FullName);
                        item.Click += new EventHandler(menuItemNewItem_Click);
                    }
                }
            }
        }

        private void menuItemNewItem_Click(object sender, EventArgs e)
        {
            MenuItem item = (MenuItem)sender;

            Type t = (Type)(this.formTypes[item.Index]);

            Object obj = Activator.CreateInstance(t);
            this.formObjects.Add(obj);
            formNum += 1;

            t.InvokeMember("MdiParent", BindingFlags.SetProperty, null, obj, new object[] {this});
            t.InvokeMember("Text", BindingFlags.SetProperty, null, obj, new object[] {t.FullName+"  窗体："+formNum});
            t.InvokeMember ("Show", BindingFlags.InvokeMethod, null, obj, new object [] {});

            ((Form)obj).Closing += new CancelEventHandler(FrmWindow_Closing);
            ((Form)obj).Activated += new EventHandler(FrmWindow_Activated);
            MenuItem menuItem = this.mnuItemWindow.MenuItems.Add(((Form)obj).Text);
            menuItem.Click += new EventHandler(menuItemWindow_Click);

            this.pnlNum.Text = "当前装载了"+this.formObjects.Count+"个窗体";
            this.pnlInfo.Text = "当前活动窗体："+this.ActiveMdiChild.Text;
        }

        private void menuItemWindow_Click(object sender, System.EventArgs e)
        {
            MenuItem item = (MenuItem)sender;

            ((Form)(this.formObjects[item.Index-4])).Activate();

            this.pnlNum.Text = "当前装载了"+this.formObjects.Count+"个窗体";
            this.pnlInfo.Text = "当前活动窗体："+this.ActiveMdiChild.Text;
        }

        private void FrmWindow_Activated(object sender, System.EventArgs e)
        {
            this.pnlNum.Text = "当前装载了"+this.formObjects.Count+"个窗体";
            this.pnlInfo.Text = "当前活动窗体："+this.ActiveMdiChild.Text;
        }

        private void FrmWindow_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            for (int i=0; i<this.formObjects.Count; i++)
            {
                if (((Form)this.formObjects[i]).Text == ((Form)sender).Text)
                {
                    this.formObjects.RemoveAt(i);
                    this.mnuItemWindow.MenuItems.RemoveAt(i+4);

                    this.pnlNum.Text = "当前装载了"+this.formObjects.Count+"个窗体";
                    this.pnlInfo.Text = "当前活动窗体："+this.ActiveMdiChild.Text;
                    break;
                }
            }
        }

        private void mnuItmCascade_Click(object sender, System.EventArgs e)
        {
            this.LayoutMdi(MdiLayout.Cascade);
        }

        private void mnuItmTileHorizontal_Click(object sender, System.EventArgs e)
        {
            this.LayoutMdi(MdiLayout.TileHorizontal);
        }

        private void mnuItmTileVertical_Click(object sender, System.EventArgs e)
        {
            this.LayoutMdi(MdiLayout.TileVertical);
        }

        private void mnuItmAbout_Click(object sender, System.EventArgs e)
        {
            new FrmAbout().ShowDialog(this);
        }
    }
}