winForm 中子窗体关闭但不释放对象，方便下次继续打开

方法一： 修改子窗体中自动生成的Dispose方法（在Form.Designer.cs文件中）

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            //if (disposing && (components != null))
            //{
            //    components.Dispose();
            //}
            //base.Dispose(disposing);
            Hide();
        }

方法二：添加子窗体FormClosing事件处理方法

        private void form***_FormClosing(object sender,     FormClosingEventArgs e)
        {
            e.Cancel = true;  //取消该事件响应

            this.Visible = false; //隐藏
        }