Winform 图形矩形大数字并将它们显示在表单/面板/选项卡上

Question

我需要在 winform 上绘制大小为 (10, 10 ) 的两种不同颜色（红色和蓝色）的动态矩形。 它的数量可以超过 100,000+。

当我在 winform 或面板中绘制它们时，它们开始重叠。 我试过滚动条，但我无法做到这一点。 当我垂直滚动它们时，形状开始变得混乱。 矩形的数量可能很多（行和列）。

private void button1_Click(object sender, EventArgs e)
        {
            tabControl2.Visible = true;

            Graphics g = FileInfoTab.CreateGraphics();
            Pen p = new Pen(Color.Black);
        for (int y = 158; y < 1000; y += 15)
        {
            for (int x = 120; x < 280; x += 15)
            {

                Random rd = new Random();
                int nm = rd.Next(0, 10);

                if (nm % 2 == 0) //if number is even draw red rectangle else blue rectangle
                {
                    SolidBrush sb = new SolidBrush(Color.Red);
                    g.DrawRectangle(p, x, y, 10, 10);
                    g.FillRectangle(sb, x, y, 10, 10);
                    //x += 15;
                }
                else
                {
                    SolidBrush sb_1 = new SolidBrush(Color.Blue);
                    g.DrawRectangle(p, x, y, 10, 10);
                    g.FillRectangle(sb_1, x, y, 10, 10);
                }
            }
        }
    }

Answer 1

从Control.CreateGraphics()创建的Graphics对象必须始终在您的代码退出之前处理，如下所述：（ CreateGraphics() 方法和 Paint Event Args ）

也许您应该考虑使用 FileInfoTab.Paint 事件：

private Bitmap Surface;
private Graphics g;

private void button1_Click(object sender, EventArgs e)
{
    RedrawSurface();
}

private void RedrawSurface()
{
    tabControl2.Visible = true;

    Surface = new Bitmap(FileInfoTab.Width, FileInfoTab.Height, PixelFormat.Format24bpprgb);
    g = Graphics.FromImage(Surface);

    Pen p = new Pen(Color.Black);
    for (int y = 158; y < 1000; y += 15)
    {
        for (int x = 120; x < 280; x += 15)
        {
            Random rd = new Random();
            int nm = rd.Next(0, 10);
            if (nm % 2 == 0)
            {
                SolidBrush sb = new SolidBrush(Color.Red);
                g.DrawRectangle(p, x, y, 10, 10);
                g.FillRectangle(sb, x, y, 10, 10);
                //x += 15;
            }
            else
            {
                SolidBrush sb_1 = new SolidBrush(Color.Blue);
                g.DrawRectangle(p, x, y, 10, 10);
                g.FillRectangle(sb_1, x, y, 10, 10);
            }
        }
    }

    g.Dispose();
    FileInfoTab.Invalidate();
}

private void FileInfoTab_Paint(object sender, PaintEventArgs e)
{
    if (Surface != null)
    {
        e.Graphics.DrawImage(Surface, 0, 0);
    }
}