C# Windows窗体间消息传递的问题

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提出Windows窗体间消息传递的问题：如何根据子窗体的状态更改父窗体的状态？如双击DataGridView的行记录后弹出修改该行记录的子窗体，在修改完数据后希望DataGridView数据刷新，这就需要子窗体通知父窗体刷新数据！
考虑在子窗体上移动鼠标，将子窗体鼠标的坐标传递给父窗体的标题栏，如何实现？反过来在父窗体上移动鼠标，如何传递给子窗体？
经典的做法为方法回调，在父窗体类中注册子窗体的MouseMove事件调用父窗体的Method直接修改标题栏；当然我们也可以将父窗体的对象指针船体给子窗体对象的tag，然后在子窗体的MouseMove事件中将tag转换为父窗体对象，然后修改其标题栏文本。回调方案不会破坏程序的逻辑，也不会破坏程序的封装；而tag对象的传递方式必须要public公开tag对象实例的方法和属性才可以！
下面分别示例两种方式实现，考虑父窗体修改子窗体如何实现？！

//target: implement mouse move on child window, call father Window's Method
//implement: before Show the ChildWindow, give EventHandler to the childWindow 
//and pick up a local method to the EvenHandler        The Callback Method!!!!
using System;
using System.Windows.Forms;

namespace infoFromWindows
{
//    TypDefName: infoFromWindows.frmFather  (02000003)
//    Flags     : [NotPublic] [AutoLayout] [Class] [AnsiClass] [BeforeFieldInit]  (00100000)
//    Extends   : 01000001 [TypeRef] System.Windows.Forms.Form
    class frmFather : System.Windows.Forms.Form
    {
        private Button btnAbout;
        
        private  frmFather()
        {
            btnAbout = new Button();
            btnAbout.ForeColor = System.Drawing.Color.Green;
            btnAbout.Text="&About Me";
            btnAbout.Click += new System.EventHandler(this.btnAboutClick);
            this.Width=400;
            this.Controls.Add(btnAbout);
        }
        
        //this method will be called from child window WHEN mouse move on Child Window
        //notice here, private void ...        question: who is the "sender"?
        private void SetChildPosToFather(object sender, MouseEventArgs e)
        {
            string strPos = string.Format( "Child Mouse POS:({0},{1})",e.X,e.Y);
            this.Text = strPos;
            
            Form about = (Form) sender;
            about.Width=400;
            about.Text=string.Format( "Current Mouse POS:({0},{1})",e.X,e.Y);
        }
        
        private void btnAboutClick(object sender,System.EventArgs e)
        {
            Form about = new Form();
            //here, we give the child window a EventHandler to call local Method!!!
            about.MouseMove += new MouseEventHandler(SetChildPosToFather);
            about.Show();
        }
                
        private static void Main()
        {
            frmFather father = new frmFather();
            Application.Run(father);
        }
    }
}

tag传递

using System;
using System.Windows.Forms;
using System.Collections.Generic;

namespace infoFromWindows
{
    public class frmAbout : Form
    {
        public frmAbout()
        {
            this.Text="I'm Child Window";
            this.MouseMove += new MouseEventHandler(changeFatherText);
        }
        
        private void changeFatherText(object sender, MouseEventArgs e)
        {
            frmFather father = (frmFather) this.Tag;
            father.Text = string.Format( "Child Mouse POS:({0},{1})",e.X,e.Y);
        }
    }
    
//    TypDefName: infoFromWindows.frmFather  (02000003)
//    Flags     : [NotPublic] [AutoLayout] [Class] [AnsiClass] [BeforeFieldInit]  (00100000)
//    Extends   : 01000001 [TypeRef] System.Windows.Forms.Form
    class frmFather : System.Windows.Forms.Form
    {
        private Button btnAbout;
        
        private void btnAboutClick(object sender,System.EventArgs e)
        {
            frmAbout about = new frmAbout();
            about.Tag = this;    
            //here,we transfer current Form POINT to "about" window, 
            //then from "about" window 
            //we can access current Form any PUBLIC method and properties.
            about.Show();
        }
        
        public frmFather()
        {
            btnAbout = new Button();
            btnAbout.ForeColor = System.Drawing.Color.Green;
            btnAbout.Text="&About Me";
            btnAbout.Click += new System.EventHandler(this.btnAboutClick);
            this.Width=400;
            this.Controls.Add(btnAbout);
        }
        
        
        public static void Main()
        {
            frmFather father = new frmFather();
            Application.Run(father);
        }
    }
}

利用回调实现双窗口通讯，尝试开启多个窗口一起测试

using System;
using System.Windows.Forms;
using System.Collections.Generic;

namespace infoFromWindows
{
    public class frmAbout : Form
    {
        public frmAbout()
        {
            this.Text="I'm Child Window";
        }
        
        
        //public, called by father window through MouseMove Event
        public void ChangeColor(object sender, MouseEventArgs e)
        {
            this.BackColor = System.Drawing.Color.FromArgb(e.X,e.Y,0);
        }
    }
    
//    TypDefName: infoFromWindows.frmFather  (02000003)
//    Flags     : [NotPublic] [AutoLayout] [Class] [AnsiClass] [BeforeFieldInit]  (00100000)
//    Extends   : 01000001 [TypeRef] System.Windows.Forms.Form
    class frmFather : System.Windows.Forms.Form
    {
        private Button btnAbout;
        
        
        public frmFather()
        {
            btnAbout = new Button();
            btnAbout.ForeColor = System.Drawing.Color.Green;
            btnAbout.Text="&About Me";
            btnAbout.Click += new System.EventHandler(this.btnAboutClick);
            this.Height=255;
            this.Width=255;
            this.MaximizeBox = false;
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
            this.Controls.Add(btnAbout);
        }
        
        private void GetChildPosCallFromFather(object sender,MouseEventArgs e)
        {
            this.Text=string.Format("({0},{1})",e.X,e.Y);
        }
        
        private void btnAboutClick(object sender,System.EventArgs e)
        {
            frmAbout about = new frmAbout();
            //here,we transfer current Form POINT to "about" window, 
            //then from "about" window 
            //we can access current Form any PUBLIC method and properties.
            about.Show();
            about.MouseMove += new MouseEventHandler(GetChildPosCallFromFather);
            this.MouseMove += new MouseEventHandler(about.ChangeColor);
        }
        
        public static void Main()
        {
            frmFather father = new frmFather();
            Application.Run(father);
        }
    }
}