c#中对mdi的操作，代码见内（child部分）

child.cs

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using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;



namespace testagain

{

    /// <summary>

    /// Summary description for child.

    /// </summary>

    public class child : System.Windows.Forms.Form

    {

        private System.Windows.Forms.Label lbl_about;

        private System.Windows.Forms.Label label1;

        /// <summary>

        /// Required designer variable.

        /// </summary>

        private System.ComponentModel.Container components = null;