鼠标拖动和放缩，已经加载到picture控件的图片

如果您想实现鼠标拖动和放缩功能，可以参考以下代码实现：

public partial class Form1 : Form
{
    private bool isDragging = false;
    private Point lastPoint;
    private int currentScale = 100;

    public Form1()
    {
        InitializeComponent();
        pictureBox1.SizeMode = PictureBoxSizeMode.Zoom;
    }

    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            isDragging = true;
            lastPoint = e.Location;
        }
    }

    private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
    {
        if (isDragging)
        {
            int deltaX = e.Location.X - lastPoint.X;
            int deltaY = e.Location.Y - lastPoint.Y;
            pictureBox1.Location = new Point(pictureBox1.Location.X + deltaX, pictureBox1.Location.Y + deltaY);
            lastPoint = e.Location;
        }
    }

    private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            isDragging = false;
        }
    }

    private void pictureBox1_MouseWheel(object sender, MouseEventArgs e)
    {
        if (e.Delta > 0 && currentScale < 500)
        {
            currentScale += 10;
        }
        else if (e.Delta < 0 && currentScale > 10)
        {
            currentScale -= 10;
        }

        pictureBox1.Width = pictureBox1.Image.Width * currentScale / 100;
        pictureBox1.Height = pictureBox1.Image.Height * currentScale / 100;
    }
}

这段代码实现了以下功能：

1. 鼠标左键拖动Picture控件移动图片位置；
2. 鼠标滚轮向上滚动放大图片，向下滚动缩小图片；
3. 放大缩小的倍数限制在10%到500%之间。

您可以将以上代码复制到Windows窗体应用程序的代码文件中，并将Picture控件的MouseDown、MouseMove、MouseUp和MouseWheel事件与对应的事件处理程序关联，然后加载一张图片到Picture控件中，就可以实现鼠标拖动和放缩已经加载到Picture控件的图片了。