AppFormBase.cs

///
/// https://stackoverflow.com/questions/7286837/how-to-move-form-in-c-net
///
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FSTimeSync
{
    public class AppFormBase : Form
    {
        protected override void OnLoad(EventArgs e)
        {
            if (this.FormBorderStyle == System.Windows.Forms.FormBorderStyle.None)
            {
                this.MouseDown += new MouseEventHandler(AppFormBase_MouseDown);
                this.MouseMove += new MouseEventHandler(AppFormBase_MouseMove);
                this.MouseUp += new MouseEventHandler(AppFormBase_MouseUp);
            }

            base.OnLoad(e);
        }

        public void RegisterMoveableControl(Control c)
        {
            if (this.FormBorderStyle == System.Windows.Forms.FormBorderStyle.None)
            {
                c.MouseDown += new MouseEventHandler(AppFormBase_MouseDown);
                c.MouseMove += new MouseEventHandler(AppFormBase_MouseMove);
                c.MouseUp += new MouseEventHandler(AppFormBase_MouseUp);
            }
        }

        void AppFormBase_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button != MouseButtons.Left)
            {
                return;
            }
            downPoint = new Point(e.X, e.Y);
        }

        void AppFormBase_MouseMove(object sender, MouseEventArgs e)
        {
            if (downPoint == Point.Empty)
            {
                return;
            }
            Point location = new Point(
                this.Left + e.X - downPoint.X,
                this.Top + e.Y - downPoint.Y);
            this.Location = location;
        }

        void AppFormBase_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button != MouseButtons.Left)
            {
                return;
            }
            downPoint = Point.Empty;
        }

        public Point downPoint = Point.Empty;
    }
}