1、首先确定一个父窗体,将IsMdiContaine设置为true。
2、创建子窗体,并且设置他们的父窗体。 
MenuStrip:显示按钮功能的分组的应用程序命令和选项。
Form.MdiParent:获取或设置此窗体的当前多文档界面(MDI)父窗体。
显示子窗体,横纵向排列:
public partial class FatherForm : System.Windows.Forms.Form{public FatherForm(){InitializeComponent();}private void 显示子窗体ToolStripMenuItem_Click(object sender, EventArgs e){//显示子窗体//使Form2的父窗体为Form1SubFormOne sub1 = new SubFormOne();sub1.MdiParent = this;sub1.Show();//使Form3的父窗体为Form1SubFormTwo sub2 = new SubFormTwo();sub2.MdiParent = this;sub2.Show();//使Form4的父窗体为Form1SubFormThree sub3 = new SubFormThree();sub3.MdiParent = this;sub3.Show();}/// <summary>/// 将所有子窗体横向排列/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void 横向排列ToolStripMenuItem_Click(object sender, EventArgs e){//LayoutMdi方法,Mdilayout枚举类型LayoutMdi(MdiLayout.TileHorizontal);}/// <summary>/// 将所有子窗体纵向排列/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void 纵向排列ToolStripMenuItem_Click(object sender, EventArgs e){LayoutMdi(MdiLayout.TileVertical);}}
