C# 无法使用变量名保存位图图像

我是C#的新手，我正试图在点击按钮时保存位图图像。我正在使用VisualStudio2010进行此操作。我可以保存我的图像，我传递一个特定的字符串作为文件名。以下是我保存图像的代码：-

    private void button1_Click(object sender, EventArgs e)
    { 

        bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
        gfxScreenshot = Graphics.FromImage(bmpScreenshot);
        gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);
        bmpScreenshot.Save("img.jpg", ImageFormat.Jpeg);
    }

但我想把这张照片保存为拍摄时的名字。因此，我在代码中添加了以下内容：-

    private void button1_Click(object sender, EventArgs e)
    { 
        string time = DateTime.Now.ToString("hh:mm:ss");
        string img = time + ".jpg";
        bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
        gfxScreenshot = Graphics.FromImage(bmpScreenshot);
        gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);
        bmpScreenshot.Save(img, ImageFormat.Jpeg);

    }

这段代码构建得很好，但当我单击我的按钮时，出现了以下异常：-

NotSupportedException was handled

---

谁能告诉我如何将我的图像名称保存为timecode。

文件名不应包含

：

。尝试将其更改为下划线或仅删除它：

private void button1_Click(object sender, EventArgs e)
{ 
    string time = DateTime.Now.ToString("HHmmss");
    string img = time + ".jpg";
    bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
    gfxScreenshot = Graphics.FromImage(bmpScreenshot);
    gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);
    bmpScreenshot.Save(img, ImageFormat.Jpeg);

}

---

你不能把

：

放在文件名里谢谢你，老兄，我被困在里面超过两个小时了。