如何在C#中绘制面板？

另一种方法是(如果你真的想在’panel1_Paint’事件处理程序之外绘制)在缓冲区图像中绘制,并将图像复制到paint事件处理程序中的控件图形对象.

更新：

一个例子：

public class Form1 : Form
{
    private Bitmap buffer;

    public Form1()
    {
        InitializeComponent();

        // Initialize buffer
        panel1_Resize(this,null);
    }

    private void panel1_Resize(object sender,EventArgs e)
    {
        // Resize the buffer,if it is growing
        if (buffer == null || 
            buffer.Width < panel1.Width || 
            buffer.Height < panel1.Height)
        {
            Bitmap newBuffer = new Bitmap(panel1.Width,panel1.Height);
            if (buffer != null)
                using (Graphics bufferGrph = Graphics.FromImage(newBuffer))
                    bufferGrph.DrawImageUnscaled(buffer,Point.Empty);
            buffer = newBuffer;
        }
    }

    private void panel1_Paint(object sender,PaintEventArgs e)
    {
        // Draw the buffer into the panel
        e.Graphics.DrawImageUnscaled(buffer,Point.Empty);
    }



    private void button1_Click(object sender,EventArgs e)
    {
        // Draw into the buffer when button is clicked
        PaintBlueRectangle();
    }

    private void PaintBlueRectangle()
    {
        // Draw blue rectangle into the buffer
        using (Graphics bufferGrph = Graphics.FromImage(buffer))
        {
            bufferGrph.DrawRectangle(new Pen(Color.Blue,1),1,100,100);
        }

        // Invalidate the panel. This will lead to a call of 'panel1_Paint'
        panel1.Invalidate();
    }
}

现在绘制的图像即使在重绘控件之后也不会丢失,因为它只绘制缓冲区(图像,保存在内存中).此外,只需绘制到缓冲区中,您就可以在事件发生时随时绘制内容.