Application類（位於System.Windows.Forms命名空間）公開了Run方法，能夠調用該方法來調度應用程序進入消息循環。Run方法有三個重載html
一、第一個重載版本不帶任何參數，比較少使用app
二、static void Run(System.Windows.Forms.Form mainForm) 調用這個重載，只須要吧但願做爲主窗口的Form實例（包括從Form類派生的類）傳遞給mianForm參數便可。一旦mainForm關閉，整個消息循環就會退出，Run方法返回，應用程序就會退出。函數
三、static void Run(System.Windows.Forms.ApplicationContext context) 這是Run方法中重載最靈活的。一般的作法是從ApplicationContext類派生，並寫入實現代碼。ApplicationContext類也容許設置一個Form實例製做爲主窗口，也能夠不設置主窗口。這個Run方法會在ApplicationContext對象進行消息循環。調用ApplicationContext類的ExitThread方法會致使ApplicationContext上的消息循環終止。post
手動建立一個類：產生三個窗口，只有把三個窗口所有關閉程序才終止運行（基於第三種Run方法）this
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
//從ApplicationContext派生一個類出來，
public class MyApplication : ApplicationContext
{
static int WindowsCount;//用於記錄窗口個數
private Form Windows1, Windows2, Windows3;//申請三個Form窗口 private只限於本類成員訪問
//構造函數，分別實例化三個窗口
public MyApplication()
{
WindowsCount = 0;
/*實例化Windows1*/
Windows1 = new Form();
Windows1.Text = "窗口1";
Windows1.Size = new System.Drawing.Size(300, 300);
Windows1.Location = new System.Drawing.Point(50, 100);
Windows1.Name = "Form1";
Windows1.FormClosed += OnMainFormClosed;//處理事件（窗口關閉的處理事件）
WindowsCount += 1;//窗口總數加一
Windows2 = new Form();
Windows2.Text = "窗口2";
Windows2.Size = new System.Drawing.Size(300, 300);
Windows2.Location = new System.Drawing.Point(50, 100);
Windows2.Name = "Form2";
Windows2.FormClosed += OnMainFormClosed;//處理事件（窗口關閉的處理事件）
WindowsCount += 1;//窗口總數加一
Windows3 = new Form();
Windows3.Text = "窗口3";
Windows3.Size = new System.Drawing.Size(300, 300);
Windows3.Location = new System.Drawing.Point(50, 100);
Windows3.Name = "Form3";
Windows3.FormClosed += OnMainFormClosed;//處理事件（窗口關閉的處理事件）
WindowsCount += 1;//窗口總數加一
//顯示3個窗口
Windows1.Show();
Windows2.Show();
Windows3.Show();
}
private void OnMainFormClosed(object sender,FormClosedEventArgs e)
{
WindowsCount -= 1;
if (WindowsCount == 0)
ExitThread();//調用ExitThead終止消息循環
}
}
namespace application1
{
static class Program
{
/// <summary>
/// 應用程序的主入口點。
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new MyApplication());
}
}
}
下面的代碼示例顯示兩個窗體，並在兩個窗體都關閉時退出應用程序。在應用程序啓動和退出時，它會記住每一個窗體的位置。此示例演示如何使用 ApplicationContext 和 Application.Run(context) 方法在啓動應用程序時顯示多個窗體。線程
類 MyApplicationContext 從 ApplicationContext 繼承，並跟蹤每一個窗體關閉的時間，而後在這兩個窗體均關閉時退出當前線程。該類爲用戶存儲每一個窗體的位置。窗體位置數據存儲在標題爲 Appdata.txt 的文件中，該文件在 UserAppDataPath 肯定的位置中建立。code
給定 ApplicationContext 的狀況下，Main 方法調用 Application.Run(context) 啓動應用程序。orm
using System;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
using System.Text;
using System.IO;
namespace ScreenSplit
{
static class Program
{
// 初始化窗體1大小及標題文本
public class AppForm1 : System.Windows.Forms.Form
{
public AppForm1()
{
Screen screen = Screen.FromRectangle(new Rectangle(0, 0, 0, 0));
this.Size = new System.Drawing.Size(screen.WorkingArea.Width / 2, screen.WorkingArea.Height);
this.Text = "AppForm1";
}
}
// 初始化窗體2大小及標題文本
public class AppForm2 : System.Windows.Forms.Form
{
public AppForm2()
{
Screen screen = Screen.FromRectangle(new Rectangle(0, 0, 0, 0));
this.Size = new System.Drawing.Size(screen.WorkingArea.Width / 2, screen.WorkingArea.Height);
this.Text = "AppForm2";
}
}
// 利用ApplicationContext類處理程序的啓動、關閉
class MyApplicationContext : ApplicationContext
{
private int formCount;
private AppForm1 form1;
private AppForm2 form2;
private Rectangle form1Position;
private Rectangle form2Position;
private FileStream userData;
private MyApplicationContext()
{
formCount = 0;
// 應用程序退出
Application.ApplicationExit += new EventHandler(this.OnApplicationExit);
try
{
// 在用戶目錄使用appdata.txt文件保存窗體退出時的位置與大小
userData = new FileStream(Application.UserAppDataPath + "//appdata.txt", FileMode.OpenOrCreate);
}
catch (IOException e)
{
// 程序退出時異常處理.
MessageBox.Show("An error occurred while attempting to show the application." +
"The error is:" + e.ToString());
// 退出當前主線程
ExitThread();
}
//窗體關閉
form1 = new AppForm1();
form1.Closed += new EventHandler(OnFormClosed);
form1.Closing += new CancelEventHandler(OnFormClosing);
formCount++;
form2 = new AppForm2();
form2.Closed += new EventHandler(OnFormClosed);
form2.Closing += new CancelEventHandler(OnFormClosing);
formCount++;
// 從文件中讀取保存窗體位置與大小的參數
if (ReadFormDataFromFile())
{
Screen screen = Screen.FromRectangle(new Rectangle(0, 0, 0, 0));
form1.Top = 0; form1.Left = 0;
form2.Top = 0; form2.Left = screen.WorkingArea.Width / 2;
form1.StartPosition = FormStartPosition.Manual;
form2.StartPosition = FormStartPosition.Manual;
form1.Bounds = form1Position;
form2.Bounds = form2Position;
}
// 顯示雙窗體
form1.Show();
form2.Show();
}
private void OnApplicationExit(object sender, EventArgs e)
{
// 保存窗體位置與大小
WriteFormDataToFile();
try
{
// 忽略窗體關閉時可能出現的錯誤
userData.Close();
}
catch { }
}
private void OnFormClosing(object sender, CancelEventArgs e)
{
// 保存窗體位置與大小
if (sender is AppForm1)
form1Position = ((Form)sender).Bounds;
else if (sender is AppForm2)
form2Position = ((Form)sender).Bounds;
}
private void OnFormClosed(object sender, EventArgs e)
{
// 關閉全部窗體，退出主線程
formCount--;
if (formCount == 0)
{
ExitThread();
}
}
private bool WriteFormDataToFile()
{
// 保存窗體位置與大小到用戶文件
UTF8Encoding encoding = new UTF8Encoding();
RectangleConverter rectConv = new RectangleConverter();
String form1pos = rectConv.ConvertToString(form1Position);
String form2pos = rectConv.ConvertToString(form2Position);
byte[] dataToWrite = encoding.GetBytes("~" + form1pos + "~" + form2pos);
try
{
userData.Seek(0, SeekOrigin.Begin);
userData.Write(dataToWrite, 0, dataToWrite.Length);
userData.Flush();
userData.SetLength(dataToWrite.Length);
return true;
}
catch
{
return false;
}
}
private bool ReadFormDataFromFile()
{
// 從文件中讀取窗體大小與位置
UTF8Encoding encoding = new UTF8Encoding();
String data;
if (userData.Length != 0)
{
byte[] dataToRead = new Byte[userData.Length];
try
{
userData.Seek(0, SeekOrigin.Begin);
userData.Read(dataToRead, 0, dataToRead.Length);
}
catch (IOException e)
{
String errorInfo = e.ToString();
return false;
}
data = encoding.GetString(dataToRead);
try
{
// 轉換數據文件爲 rectangles
RectangleConverter rectConv = new RectangleConverter();
String form1pos = data.Substring(1, data.IndexOf("~", 1) - 1);
form1Position = (Rectangle)rectConv.ConvertFromString(form1pos);
String form2pos = data.Substring(data.IndexOf("~", 1) + 1);
form2Position = (Rectangle)rectConv.ConvertFromString(form2pos);
return true;
}
catch
{
return false;
}
}
else
{
// 無數據文件時，缺省窗體位置與大小
return false;
}
}
[STAThread]
static void Main(string[] args)
{
MyApplicationContext context = new MyApplicationContext();
Application.Run(context);
}
}
}
}
//以上代碼保存成Program.cs，修改form名稱後能夠直接使用。源自MSDN，稍做修改