本文實例為大家分享了C# picturebox實現圖像拖拽和縮放的具體代碼，供大家參考，具體內容如下
1.核心步驟：
①新建Point類型全局變量mouseDownPoint，記錄拖拽過程中鼠標位置；
②MouseDown事件記錄Cursor位置；
③MouseMove事件計算移動矢量，并更新pictureBox1.Location。
代碼：
private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { mouseDownPoint.X = Cursor.Position.X; //記錄鼠標左鍵按下時位置 mouseDownPoint.Y = Cursor.Position.Y; isMove = true; pictureBox1.Focus(); //鼠標滾輪事件(縮放時)需要picturebox有焦點 } } private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { isMove = false; } } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { pictureBox1.Focus(); //鼠標在picturebox上時才有焦點，此時可以縮放 if (isMove) { int x, y; //新的pictureBox1.Location(x,y) int moveX, moveY; //X方向，Y方向移動大小。 moveX = Cursor.Position.X - mouseDownPoint.X; moveY = Cursor.Position.Y - mouseDownPoint.Y; x = pictureBox1.Location.X + moveX; y = pictureBox1.Location.Y + moveY; pictureBox1.Location = new Point(x, y); mouseDownPoint.X = Cursor.Position.X; mouseDownPoint.Y = Cursor.Position.Y; } } private void panel2_MouseDown(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { mouseDownPoint.X = Cursor.Position.X; //記錄鼠標左鍵按下時位置 mouseDownPoint.Y = Cursor.Position.Y; isMove = true; } } private void panel2_MouseUp(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { isMove = false; } } private void panel2_MouseMove(object sender, MouseEventArgs e) { panel2.Focus(); //鼠標不在picturebox上時焦點給別的控件，此時無法縮放 if (isMove) { int x, y; //新的pictureBox1.Location(x,y) int moveX, moveY; //X方向，Y方向移動大小。 moveX = Cursor.Position.X - mouseDownPoint.X; moveY = Cursor.Position.Y - mouseDownPoint.Y; x = pictureBox1.Location.X + moveX; y = pictureBox1.Location.Y + moveY; pictureBox1.Location = new Point(x, y); mouseDownPoint.X = Cursor.Position.X; mouseDownPoint.Y = Cursor.Position.Y; } }2.圖像縮放
核心思想：利用picturebox的zoom模式，根據圖像顯示大小更改picturebox大小，記錄鼠標位置補償縮放位移，實現錨點縮放，即以鼠標位置為中心進行縮放。
zoomstep --- 自己定義滾輪滑動縮放大小
代碼：
//實現錨點縮放(以鼠標所指位置為中心縮放)； //步驟： //①先改picturebox長寬，長寬改變量一樣； //②獲取縮放后picturebox中實際顯示圖像的長寬，這里長寬是不一樣的； //③將picturebox的長寬設置為顯示圖像的長寬； //④補償picturebox因縮放產生的位移，實現錨點縮放。 // 注釋：為啥要②③步？由于zoom模式的機制，把picturebox背景設為黑就知道為啥了。 //這里需要獲取zoom模式下picturebox所顯示圖像的大小信息，添加 using System.Reflection； //pictureBox1_MouseWheel事件沒找到。。。手動添加，別忘在Form1.Designer.cs的“Windows 窗體設計器生成的代碼”里加入： //this.pictureBox1.MouseWheel += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseWheel)。 private void pictureBox1_MouseWheel(object sender, MouseEventArgs e) { int x = e.Location.X; int y = e.Location.Y; int ow = pictureBox1.Width; int oh = pictureBox1.Height; int VX, VY; //因縮放產生的位移矢量 if (e.Delta > 0) //放大 { //第①步 pictureBox1.Width += zoomStep; pictureBox1.Height += zoomStep; //第②步 PropertyInfo pInfo = pictureBox1.GetType().GetProperty("ImageRectangle", BindingFlags.Instance | BindingFlags.NonPublic); Rectangle rect = (Rectangle)pInfo.GetValue(pictureBox1, null); //第③步 pictureBox1.Width = rect.Width; pictureBox1.Height = rect.Height; } if (e.Delta < 0) //縮小 { //防止一直縮成負值 if (pictureBox1.Width < myBmp.Width / 10) return; pictureBox1.Width -= zoomStep; pictureBox1.Height -= zoomStep; PropertyInfo pInfo = pictureBox1.GetType().GetProperty("ImageRectangle", BindingFlags.Instance | BindingFlags.NonPublic); Rectangle rect = (Rectangle)pInfo.GetValue(pictureBox1, null); pictureBox1.Width = rect.Width; pictureBox1.Height = rect.Height; } //第④步，求因縮放產生的位移，進行補償，實現錨點縮放的效果 VX = (int)((double)x * (ow - pictureBox1.Width) / ow); VY = (int)((double)y * (oh - pictureBox1.Height) / oh); pictureBox1.Location = new Point(pictureBox1.Location.X + VX, pictureBox1.Location.Y + VY);}以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
新聞熱點
疑難解答
