Progress which doesn't throw exceptions for invalid input parameters

WinFormsProgress.cs

public void Progress(long current, long total)
{
	if (InvokeRequired)
	{
		BeginInvoke(new Action<long, long>(Progress), current, total);
	}
	else
	{
		if (total <= 0 || current <= 0)
		{
			progressBar1.Value = 0;
		}
		else
		{
			progressBar1.Maximum = 100;

			if (current > total)
				current = total;

			var percent = Convert.ToInt32((current / new decimal(total)) * 100);

			if (percent > 100)
				percent = 100;

			if (percent < 0)
				percent = 0;
  		progressBar1.Value = percent;
		}
	}
}