基于C#实现磁性吸附窗体

public partial class Frm_Libretto : FORM
{
    public Frm_Libretto()
    {
        InitializeComponent();
    }

    #region 公共变量

    FrmClass Cla_FrmClass = new FrmClass();

    #endregion

    private void Frm_Libretto_Load(object sender, EventArgs e)
    {
        this.Top = FrmClass.Example_Play_Top;
        this.Left = FrmClass.Example_Play_Left + FrmClass.Example_Play_Width;
        Cla_FrmClass.FrmInitialize(this);
    }

    private void panel_Title_MouseDown(object sender, MouseEventArgs e)
    {
        FrmClass.CPoint = new Point(-e.X, -e.Y);
    }

    private void panel_Title_MouseMove(object sender, MouseEventArgs e)
    {
        FrmClass.Example_Assistant_AdhereTo = false;
        FrmClass.Example_Libretto_AdhereTo = false;
        Cla_FrmClass.FrmMove(this, e);
    }

    private void panel_Title_MouseUp(object sender, MouseEventArgs e)
    {
        Cla_FrmClass.FrmPlace(this);
    }
}

public partial class Frm_ListBox : Form
{
    public Frm_ListBox()
    {
        InitializeComponent();
    }

    #region  公共变量
    FrmClass Cla_FrmClass = new FrmClass();
    #endregion

    private void Frm_ListBox_Load(object sender, EventArgs e)
    {
        this.Left = FrmClass.Example_Play_Left;
        this.Top = FrmClass.Example_Play_Top + FrmClass.Example_Play_Height;
        Cla_FrmClass.FrmInitialize(this);
    }

    private void panel_Title_MouseDown(object sender, MouseEventArgs e)
    {
        FrmClass.CPoint = new Point(-e.X, -e.Y);
    }

    private void panel_Title_MouseMove(object sender, MouseEventArgs e)
    {
        FrmClass.Example_Assistant_AdhereTo = false;
        FrmClass.Example_List_AdhereTo = false;
        Cla_FrmClass.FrmMove(this, e);
    }

    private void panel_Title_MouseUp(object sender, MouseEventArgs e)
    {
        Cla_FrmClass.FrmPlace(this);
    }
}

public partial class Frm_Play : Form
{
    public Frm_Play()
    {
        InitializeComponent();
    }

    #region 公共变量

    FrmClass Cla_FrmClass = new FrmClass();
    public static Form F_List = new Form();
    public static Form F_Libretto = new Form();
    public static Form F_Screen = new Form();

    #endregion

    private void Frm_Play_Load(object sender, EventArgs e)
    {
        //窗体位置的初始化
        Cla_FrmClass.FrmInitialize(this);
    }

    private void panel_Title_MouseDown(object sender, MouseEventArgs e)
    {
        int Tem_Y = 0;
        if (e.Button == MouseButtons.Left) //按下的是否为鼠标左键
        {
            Cla_FrmClass.FrmBackCheck(); //检测各窗体是否连在一起
            Tem_Y = e.Y;
            FrmClass.FrmPoint = new Point(e.X, Tem_Y); //获取鼠标在窗体上的位置，用于磁性窗体
            FrmClass.CPoint = new Point(-e.X, -Tem_Y); //获取鼠标在屏幕上的位置，用于窗体的移动
            if (FrmClass.Example_List_AdhereTo) //如果与frm_ListBox窗体相连接
            {
                Cla_FrmClass.FrmDistanceJob(this, F_List); //计算窗体的距离差
                if (FrmClass.Example_Assistant_AdhereTo) //两个辅窗体是否连接在一起
                {
                    Cla_FrmClass.FrmDistanceJob(this, F_Libretto); //计算窗体的距离差
                }
            }

            if (FrmClass.Example_Libretto_AdhereTo) //如果与frm_Libretto窗体相连接
            {
                Cla_FrmClass.FrmDistanceJob(this, F_Libretto); //计算窗体的距离差
                if (FrmClass.Example_Assistant_AdhereTo) //两个辅窗体是否连接在一起
                {
                    Cla_FrmClass.FrmDistanceJob(this, F_List); //计算窗体的距离差
                }
            }
        }
    }

    private void panel_Title_MouseMove(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left) //按下的是否为鼠标左键
        {
            Cla_FrmClass.FrmMove(this, e); //利用控件移动窗体
            if (FrmClass.Example_List_AdhereTo) //如果frm_ListBox窗体与主窗体连接
            {
                Cla_FrmClass.ManyFrmMove(this, e, F_List); //磁性窗体的移动
                Cla_FrmClass.FrmInitialize(F_List); //对frm_ListBox窗体的位置进行初始化
                if (FrmClass.Example_Assistant_AdhereTo) //如果两个子窗体连接在一起
                {
                    Cla_FrmClass.ManyFrmMove(this, e, F_Libretto);
                    Cla_FrmClass.FrmInitialize(F_Libretto);
                }
            }

            if (FrmClass.Example_Libretto_AdhereTo) //如果frm_Libretto窗体与主窗体连接
            {
                Cla_FrmClass.ManyFrmMove(this, e, F_Libretto);
                Cla_FrmClass.FrmInitialize(F_Libretto);
                if (FrmClass.Example_Assistant_AdhereTo)
                {
                    Cla_FrmClass.ManyFrmMove(this, e, F_List);
                    Cla_FrmClass.FrmInitialize(F_List);
                }
            }

            Cla_FrmClass.FrmInitialize(this);
        }
    }

    private void panel_Title_MouseUp(object sender, MouseEventArgs e)
    {
        Cla_FrmClass.FrmPlace(this);
    }

    private void Frm_Play_Shown(object sender, EventArgs e)
    {
        //显示列表窗体
        F_List = new Frm_ListBox();
        F_List.ShowInTaskbar = false;
        FrmClass.Example_ListShow = true;
        F_List.Show();
        //显示歌词窗体
        F_Libretto = new Frm_Libretto();
        F_Libretto.ShowInTaskbar = false;
        FrmClass.Example_LibrettoShow = true;
        F_Libretto.Show();
        F_Libretto.Left = this.Left + this.Width;
        F_Libretto.Top = this.Top;
        //各窗体位置的初始化
        Cla_FrmClass.FrmInitialize(F_List);
        Cla_FrmClass.FrmInitialize(F_Libretto);
    }

    private void panel_Close_Click(object sender, EventArgs e)
    {
        F_List.Close();
        F_List.Dispose();
        F_Libretto.Close();
        F_Libretto.Dispose();
        F_Screen.Close();
        F_Screen.Dispose();
        this.Close();
    }

    private void panel_Title_Click(object sender, EventArgs e)
    {
        F_List.Focus();
        F_Libretto.Focus();
        this.Focus();
    }
}

class FrmClass
{
    #region 磁性窗体-公共变量

    //记录窗体的隐藏与显示
    public static bool Example_ListShow = false;
    public static bool Example_LibrettoShow = false;
    public static bool Example_ScreenShow = false;

    //记录鼠标的当前位置
    public static Point CPoint; //添加命名空间using System.Drawing;
    public static Point FrmPoint;
    public static int Example_FSpace = 10; //设置窗体间的距离

    //Frm_Play窗体的位置及大小
    public static int Example_Play_Top = 0;
    public static int Example_Play_Left = 0;
    public static int Example_Play_Width = 0;
    public static int Example_Play_Height = 0;
    public static bool Example_Assistant_AdhereTo = false; //辅助窗体是否磁性在一起

    //Frm_ListBos窗体的位置及大小
    public static int Example_List_Top = 0;
    public static int Example_List_Left = 0;
    public static int Example_List_Width = 0;
    public static int Example_List_Height = 0;
    public static bool Example_List_AdhereTo = false; //辅助窗体是否与主窗体磁性在一起

    //Frm_Libretto窗体的位置及大小
    public static int Example_Libretto_Top = 0;
    public static int Example_Libretto_Left = 0;
    public static int Example_Libretto_Width = 0;
    public static int Example_Libretto_Height = 0;
    public static bool Example_Libretto_AdhereTo = false; //辅助窗体是否与主窗体磁性在一起

    //窗体之间的距离差
    public static int Example_List_space_Top = 0;
    public static int Example_List_space_Left = 0;
    public static int Example_Libretto_space_Top = 0;
    public static int Example_Libretto_space_Left = 0;

    #endregion

    #region 检测各窗体是否连接在一起

    /// <summary>
    /// 检测各窗体是否连接在一起
    /// </summary>
    public void FrmBackCheck()
    {
        bool Tem_Magnetism = false;
        //Frm_ListBos与主窗体
        Tem_Magnetism = false;
        if ((Example_Play_Top - Example_List_Top) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Left - Example_List_Left) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Left - Example_List_Left - Example_List_Width) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Left - Example_List_Left + Example_List_Width) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Top - Example_List_Top - Example_List_Height) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Top - Example_List_Top + Example_List_Height) == 0)
            Tem_Magnetism = true;
        if (Tem_Magnetism)
            Example_List_AdhereTo = true;

        //Frm_Libretto与主窗体
        Tem_Magnetism = false;
        if ((Example_Play_Top - Example_Libretto_Top) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Left - Example_Libretto_Left) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Left - Example_Libretto_Left - Example_Libretto_Width) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Left - Example_Libretto_Left + Example_Libretto_Width) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Top - Example_Libretto_Top - Example_Libretto_Height) == 0)
            Tem_Magnetism = true;
        if ((Example_Play_Top - Example_Libretto_Top + Example_Libretto_Height) == 0)
            Tem_Magnetism = true;
        if (Tem_Magnetism)
            Example_Libretto_AdhereTo = true;

        //两个辅窗体
        Tem_Magnetism = false;
        if ((Example_List_Top - Example_Libretto_Top) == 0)
            Tem_Magnetism = true;
        if ((Example_List_Left - Example_Libretto_Left) == 0)
            Tem_Magnetism = true;
        if ((Example_List_Left - Example_Libretto_Left - Example_Libretto_Width) == 0)
            Tem_Magnetism = true;
        if ((Example_List_Left - Example_Libretto_Left + Example_Libretto_Width) == 0)
            Tem_Magnetism = true;
        if ((Example_List_Top - Example_Libretto_Top - Example_Libretto_Height) == 0)
            Tem_Magnetism = true;
        if ((Example_List_Top - Example_Libretto_Top + Example_Libretto_Height) == 0)
            Tem_Magnetism = true;
        if (Tem_Magnetism)
            Example_Assistant_AdhereTo = true;
    }

    #endregion

    #region 利用窗体上的控件移动窗体

    /// <summary>
    /// 利用控件移动窗体
    /// </summary>
    /// <param Frm="Form">窗体</param>
    /// <param e="MouseEventArgs">控件的移动事件</param>
    public void FrmMove(Form Frm, MouseEventArgs e) //Form或MouseEventArgs添加命名空间using System.windows.Forms;
    {
        if (e.Button == MouseButtons.Left)
        {
            Point myPosittion = Control.MousePosition; //获取当前鼠标的屏幕坐标
            myPosittion.Offset(CPoint.X, CPoint.Y); //重载当前鼠标的位置
            Frm.DesktopLocation = myPosittion; //设置当前窗体在屏幕上的位置
        }
    }

    #endregion

    #region 计算窗体之间的距离差

    /// <summary>
    /// 计算窗体之间的距离差
    /// </summary>
    /// <param Frm="Form">窗体</param>
    /// <param Follow="Form">跟随窗体</param>
    public void FrmDistanceJob(Form Frm, Form Follow)
    {
        switch (Follow.Name)
        {
            case "Frm_ListBox":
            {
                Example_List_space_Top = Follow.Top - Frm.Top;
                Example_List_space_Left = Follow.Left - Frm.Left;
                break;
            }
            case "Frm_Libretto":
            {
                Example_Libretto_space_Top = Follow.Top - Frm.Top;
                Example_Libretto_space_Left = Follow.Left - Frm.Left;
                break;
            }
        }
    }

    #endregion

    #region 磁性窗体的移动

    /// <summary>
    /// 磁性窗体的移动
    /// </summary>
    /// <param Frm="Form">窗体</param>
    /// <param e="MouseEventArgs">控件的移动事件</param>
    /// <param Follow="Form">跟随窗体</param>
    public void
        ManyFrmMove(Form Frm, MouseEventArgs e, Form Follow) //Form或MouseEventArgs添加命名空间using System.Windows.Forms;
    {
        if (e.Button == MouseButtons.Left)
        {
            int Tem_Left = 0;
            int Tem_Top = 0;
            Point myPosittion = Control.MousePosition; //获取当前鼠标的屏幕坐标
            switch (Follow.Name)
            {
                case "Frm_ListBox":
                {
                    Tem_Top = Example_List_space_Top - FrmPoint.Y;
                    Tem_Left = Example_List_space_Left - FrmPoint.X;
                    break;
                }
                case "Frm_Libretto":
                {
                    Tem_Top = Example_Libretto_space_Top - FrmPoint.Y;
                    Tem_Left = Example_Libretto_space_Left - FrmPoint.X;
                    break;
                }
            }

            myPosittion.Offset(Tem_Left, Tem_Top);
            Follow.DesktopLocation = myPosittion;
        }
    }

    #endregion

    #region 对窗体的位置进行初始化

    /// <summary>
    /// 对窗体的位置进行初始化
    /// </summary>
    /// <param Frm="Form">窗体</param>
    public void FrmInitialize(Form Frm)
    {
        switch (Frm.Name)
        {
            case "Frm_Play":
            {
                Example_Play_Top = Frm.Top;
                Example_Play_Left = Frm.Left;
                Example_Play_Width = Frm.Width;
                Example_Play_Height = Frm.Height;
                break;
            }
            case "Frm_ListBox":
            {
                Example_List_Top = Frm.Top;
                Example_List_Left = Frm.Left;
                Example_List_Width = Frm.Width;
                Example_List_Height = Frm.Height;
                break;
            }
            case "Frm_Libretto":
            {
                Example_Libretto_Top = Frm.Top;
                Example_Libretto_Left = Frm.Left;
                Example_Libretto_Width = Frm.Width;
                Example_Libretto_Height = Frm.Height;
                break;
            }
        }
    }

    #endregion

    #region 存储各窗体的当前信息

    /// <summary>
    /// 存储各窗体的当前信息
    /// </summary>
    /// <param Frm="Form">窗体</param>
    /// <param e="MouseEventArgs">控件的移动事件</param>
    public void FrmPlace(Form Frm)
    {
        FrmInitialize(Frm);
        FrmMagnetism(Frm);
    }

    #endregion

    #region 窗体的磁性设置

    /// <summary>
    /// 窗体的磁性设置
    /// </summary>
    /// <param Frm="Form">窗体</param>
    public void FrmMagnetism(Form Frm)
    {
        if (Frm.Name != "Frm_Play")
        {
            FrmMagnetismCount(Frm, Example_Play_Top, Example_Play_Left, Example_Play_Width, Example_Play_Height,
                "Frm_Play");
        }

        if (Frm.Name != "Frm_ListBos")
        {
            FrmMagnetismCount(Frm, Example_List_Top, Example_List_Left, Example_List_Width, Example_List_Height,
                "Frm_ListBos");
        }

        if (Frm.Name != "Frm_Libratto")
        {
            FrmMagnetismCount(Frm, Example_Libretto_Top, Example_Libretto_Left, Example_Libretto_Width,
                Example_Libretto_Height, "Frm_Libratto");
        }

        FrmInitialize(Frm);
    }

    #endregion

    #region 磁性窗体的计算

    /// <summary>
    /// 磁性窗体的计算
    /// </summary>
    /// <param Frm="Form">窗体</param>
    /// <param e="MouseEventArgs">控件的移动事件</param>
    public void FrmMagnetismCount(Form Frm, int top, int left, int width, int height, string Mforms)
    {
        bool Tem_Magnetism = false; //判断是否有磁性发生
        string Tem_MainForm = ""; //临时记录主窗体
        string Tem_AssistForm = ""; //临时记录辅窗体

        //上面进行磁性窗体
        if ((Frm.Top + Frm.Height - top) <= Example_FSpace && (Frm.Top + Frm.Height - top) >= -Example_FSpace)
        {
            //当一个主窗体不包含辅窗体时
            if ((Frm.Left >= left && Frm.Left <= (left + width)) ||
                ((Frm.Left + Frm.Width) >= left && (Frm.Left + Frm.Width) <= (left + width)))
            {
                Frm.Top = top - Frm.Height;
                if ((Frm.Left - left) <= Example_FSpace && (Frm.Left - left) >= -Example_FSpace)
                    Frm.Left = left;
                Tem_Magnetism = true;
            }

            //当一个主窗体包含辅窗体时
            if (Frm.Left <= left && (Frm.Left + Frm.Width) >= (left + width))
            {
                Frm.Top = top - Frm.Height;
                if ((Frm.Left - left) <= Example_FSpace && (Frm.Left - left) >= -Example_FSpace)
                    Frm.Left = left;
                Tem_Magnetism = true;
            }
        }

        //下面进行磁性窗体
        if ((Frm.Top - (top + height)) <= Example_FSpace && (Frm.Top - (top + height)) >= -Example_FSpace)
        {
            //当一个主窗体不包含辅窗体时
            if ((Frm.Left >= left && Frm.Left <= (left + width)) ||
                ((Frm.Left + Frm.Width) >= left && (Frm.Left + Frm.Width) <= (left + width)))
            {
                Frm.Top = top + height;
                if ((Frm.Left - left) <= Example_FSpace && (Frm.Left - left) >= -Example_FSpace)
                    Frm.Left = left;
                Tem_Magnetism = true;
            }

            //当一个主窗体包含辅窗体时
            if (Frm.Left <= left && (Frm.Left + Frm.Width) >= (left + width))
            {
                Frm.Top = top + height;
                if ((Frm.Left - left) <= Example_FSpace && (Frm.Left - left) >= -Example_FSpace)
                    Frm.Left = left;
                Tem_Magnetism = true;
            }
        }

        //左面进行磁性窗体
        if ((Frm.Left + Frm.Width - left) <= Example_FSpace && (Frm.Left + Frm.Width - left) >= -Example_FSpace)
        {
            //当一个主窗体不包含辅窗体时
            if ((Frm.Top > top && Frm.Top <= (top + height)) ||
                ((Frm.Top + Frm.Height) >= top && (Frm.Top + Frm.Height) <= (top + height)))
            {
                Frm.Left = left - Frm.Width;
                if ((Frm.Top - top) <= Example_FSpace && (Frm.Top - top) >= -Example_FSpace)
                    Frm.Top = top;
                Tem_Magnetism = true;
            }

            //当一个主窗体包含辅窗体时
            if (Frm.Top <= top && (Frm.Top + Frm.Height) >= (top + height))
            {
                Frm.Left = left - Frm.Width;
                if ((Frm.Top - top) <= Example_FSpace && (Frm.Top - top) >= -Example_FSpace)
                    Frm.Top = top;
                Tem_Magnetism = true;
            }
        }

        //右面进行磁性窗体
        if ((Frm.Left - (left + width)) <= Example_FSpace && (Frm.Left - (left + width)) >= -Example_FSpace)
        {
            //当一个主窗体不包含辅窗体时
            if ((Frm.Top > top && Frm.Top <= (top + height)) ||
                ((Frm.Top + Frm.Height) >= top && (Frm.Top + Frm.Height) <= (top + height)))
            {
                Frm.Left = left + width;
                if ((Frm.Top - top) <= Example_FSpace && (Frm.Top - top) >= -Example_FSpace)
                    Frm.Top = top;
                Tem_Magnetism = true;
            }

            //当一个主窗体包含辅窗体时
            if (Frm.Top <= top && (Frm.Top + Frm.Height) >= (top + height))
            {
                Frm.Left = left + width;
                if ((Frm.Top - top) <= Example_FSpace && (Frm.Top - top) >= -Example_FSpace)
                    Frm.Top = top;
                Tem_Magnetism = true;
            }
        }

        if (Frm.Name == "Frm_Play")
            Tem_MainForm = "Frm_Play";
        else
            Tem_AssistForm = Frm.Name;
        if (Mforms == "Frm_Play")
            Tem_MainForm = "Frm_Play";
        else
            Tem_AssistForm = Mforms;
        if (Tem_MainForm == "")
        {
            Example_Assistant_AdhereTo = Tem_Magnetism;
        }
        else
        {
            switch (Tem_AssistForm)
            {
                case "Frm_ListBos":
                    Example_List_AdhereTo = Tem_Magnetism;
                    break;
                case "Frm_Libratto":
                    Example_Libretto_AdhereTo = Tem_Magnetism;
                    break;
            }
        }
    }

    #endregion

    #region 恢复窗体的初始大小

    /// <summary>
    /// 恢复窗体的初始大小(当松开鼠标时，如果窗体的大小小于300*200,恢复初始状态)
    /// </summary>
    /// <param Frm="Form">窗体</param>
    public void FrmScreen_FormerlySize(Form Frm, int PWidth, int PHeight)
    {
        if (Frm.Width < PWidth || Frm.Height < PHeight)
        {
            Frm.Width = PWidth;
            Frm.Height = PHeight;
            //Example_Size = false;
        }
    }

    #endregion
}

static class Program
{
    /// <summary>
    /// 应用程序的主入口点。
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Frm_Play());
    }
}