C#实现图片的剪切功能

【实例简介】

实现图片的剪切，截图等功能。

【实例截图】

【核心代码】

public partial class FMDragPictureBox : Form
    {
        public FMDragPictureBox()
        {
            InitializeComponent();
        }
        private const byte Ctrl = 8;//表示按住了Ctrl键（类似的还有Alt、Shift、鼠标左键、鼠标右键等键的常数定义，请查看MSDN）
        Image mouseImg;//额，拖拽的图片

        private void DragPictureBox_Load(object sender, EventArgs e)
        {
            string strHeadImagePath = AppDomain.CurrentDomain.SetupInformation.ApplicationBase   "temp.JPG";
            Bitmap Bi = new Bitmap(strHeadImagePath);  //使用打开的图片路径创建位图对像
            pictureBoxLeft.Image = Bi;

            // 决定是否允许拖放 
            pictureBoxLeft.AllowDrop = true;


            pictureBoxLeft.DragDrop  = new System.Windows.Forms.DragEventHandler(this.PictureBox_DragDrop);
            pictureBoxLeft.DragEnter  = new System.Windows.Forms.DragEventHandler(this.PictureBox_DragEnter);
            pictureBoxLeft.MouseDown  = new System.Windows.Forms.MouseEventHandler(this.PictureBox_MouseDown);
        }

        #region 鼠标拖动图片

        /// <summary>
        /// 拖拽后松开鼠标
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void PictureBox_DragDrop(object sender, DragEventArgs e)
        {
            PictureBox pc = sender as PictureBox; //从sender对象里取出目标事件PictureBox控件
            pc.Image = e.Data.GetData(DataFormats.Bitmap) as Bitmap;//从事件参数中取出拖动的数据，并转换为图象对象
              //MessageBox.Show("松开鼠标了，图片在哪儿！！！");//在这个控件里，松开，才会进来

            //if (e.KeyState != Ctrl) //若不是执行的拷贝操作
            //{
            //    //且是把图片放置到picLeft控件，那么picRight控件显示的图片将被清除；反之亦然。
                //if (pc.Name == "picLeft")
                //{
                //    pc.Image = null;
                //}
                //else
                //{
                //    pc.ImageLocation = null;
                //}
            //}
        }

        /// <summary>
        /// 在用鼠标将某项拖放到该控件的工作区时发生
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void PictureBox_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.Bitmap)) //检查拖动的数据是否适合于目标空间类型；若不适合，则拒绝放置。
            {
                if (e.KeyState == Ctrl)  //检查Ctrl键是否被按住
                {
                    e.Effect = DragDropEffects.Copy; //若Ctrl键被按住，则设置拖放类型为拷贝
                }
                else
                {
                    e.Effect = DragDropEffects.Move; //若Ctrl键没有被按住，则设置拖放类型为移动
                }
            }
            else
            {
                e.Effect = DragDropEffects.None;  //若被拖动的数据不适合于目标控件，则设置拖放类型为拒绝放置
            }
        }

        /// <summary>
        /// 鼠标按下事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void PictureBox_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left) //判断是否按下鼠标左键
            {
                PictureBox pc = sender as PictureBox;//从sender对象里取出源事件PictureBox控件

                if (pc.Image != null) //判断事件源对象是否正显示了图片
                {
                    //开始拖放操作，并传递要拖动的数据以及拖放的类型（是移动操作还是拷贝操作）
                    pc.DoDragDrop(pc.Image, DragDropEffects.Copy | DragDropEffects.Move);
                }

                /*************写变量了****************/
                mouseImg = pc.Image;

                /*****************************/
                ////pictureBoxRight.AllowDrop = true;//目标控件1
                ////pictureBoxRight.BackColor = Color.Transparent;
                ////SetStyle(ControlStyles.SupportsTransparentBackColor, true);
                ////pictureBoxRight.Image = pc.Image;
                ////pictureBoxRight.ImageLocation = pc.ImageLocation;


                ////、、目标控件2
                //pictureBox1.AllowDrop = true;
                //pictureBox1.BackColor = Color.Transparent;
                //SetStyle(ControlStyles.SupportsTransparentBackColor, true);
                //pictureBox1.Image = pc.Image;
                //pictureBox1.ImageLocation = pc.ImageLocation;
            }
        }



        #endregion

        /// <summary>
        /// 弹出框选择图片
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter = "*.gif|*.jpg|*.JPEG|*.JPEG|*.bmp|*.bmp";         //设置读取图片类型
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    string strHeadImagePath = openFileDialog1.FileName;
                    txtAddress.Text = strHeadImagePath;
                    Bitmap Bi = new Bitmap(strHeadImagePath);  //使用打开的图片路径创建位图对像
                    pictureBoxLeft.Image = Bi;
                }
                catch (Exception ex)
                {
                    MessageBox.Show("格式不对");
                    ex.ToString();
                }
            }
        }



        private void pictureBoxRight1_MouseUp(object sender, MouseEventArgs e)
        {
            if (mouseImg!=null)
            {
                pictureBoxRight1.Image = mouseImg;
                mouseImg = null;
            }
            else
            {
                MessageBox.Show("变量无知额1");
            }

        }

      
        private void pictureBoxRight2_MouseUp(object sender, MouseEventArgs e)
        {
            if (mouseImg != null)
            {
                //MessageBox.Show("变量可是有值二");
                pictureBoxRight2.Image = mouseImg;
                mouseImg = null;
            }
            else
            {
                MessageBox.Show("变量无知额2");
            }
        }

     
    }