拖动PictureBox 代码片断

最新推荐文章于 2020-04-27 20:21:13 发布

转载最新推荐文章于 2020-04-27 20:21:13 发布 · 87 阅读

本文介绍了两种实现PictureBox拖动的方法，并提供了一段用于自定义UserControl边框绘制的代码。第一种方法通过监听PictureBox的鼠标事件来实现拖动功能；第二种方法利用了Windows API实现更为灵活的拖动效果。

Code
        Point p = new Point();
        public Form1()
        {
            InitializeComponent();
            this.pictureBox1.MouseUp += new MouseEventHandler(pictureBox1_MouseUp);
            this.pictureBox1.MouseDown += new MouseEventHandler(pictureBox1_MouseDown);
            this.pictureBox1.MouseMove += new MouseEventHandler(pictureBox1_MouseMove);
        }

        #region capture picturebox
        void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            if (this.pictureBox1.Capture)
            {
                this.pictureBox1.Left = this.pictureBox1.Left + (Cursor.Position.X - p.X);
                this.pictureBox1.Top = this.pictureBox1.Top + (Cursor.Position.Y - p.Y);
                p.X = Cursor.Position.X;
                p.Y = Cursor.Position.Y;
            }
        }

        void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            this.pictureBox1.Capture = false;
        }

        void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            this.pictureBox1.Capture = true;
            p.X = Cursor.Position.X;
            p.Y = Cursor.Position.Y;
        }
        #endregion

另一种方法

Code
        private void pictureBox1_MouseDown( object sender, MouseEventArgs e ) {
            PictureBox1MouseDown( sender, e );
            //this.pictureBox1.BringToFront();
        }

        const uint WM_SYSCOMMAND = 0x0112;
        const uint SC_MOVE = 0xF010;
        const uint HTCAPTION = 0x0002;

        [DllImport( "user32.dll", EntryPoint = "SendMessageA" )]
        private static extern int SendMessage( IntPtr hwnd, uint wMsg, uint wParam, uint lParam );
        [DllImport( "user32.dll" )]
        private static extern int ReleaseCapture();

        void PictureBox1MouseDown( object sender, MouseEventArgs e ) {
            ReleaseCapture();
            SendMessage( ( sender as Control ).Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0 );
            this.Validate();
        }

重画UserControl的边框代码,暂时有一个问题没搞定,就是这个边框是画上去,没有实际的范围"约束",我指子控件可以放到"边"上边,很不爽,继续研究ing...

Code
        private Pen borderPen;
        public TstringBox() {
            InitializeComponent();
            this.SetStyle( ControlStyles.AllPaintingInWmPaint, true );
            this.SetStyle( ControlStyles.OptimizedDoubleBuffer, true );
            this.SetStyle( ControlStyles.ResizeRedraw, true );
            this.SetStyle( ControlStyles.UserPaint, true );
            this.SetStyle( ControlStyles.SupportsTransparentBackColor, true );
            borderPen = new Pen( Color.FromArgb( 179, 179, 179 ) );
        }

        protected override void OnPaint( PaintEventArgs e ) {
            e.Graphics.Clear( Color.White );
            e.Graphics.DrawRectangle( borderPen, new Rectangle( this.ClientRectangle.Location, new Size( this.ClientRectangle.Size.Width - 3,this.ClientRectangle.Size.Height - 3 ) ) );
            base.OnPaint( e );
        }