打印图片框

当我尝试打印一个PictureBox时，抛出一个ArgumentException(参数无效)。

这是打印功能:

void pdGroupBox_PrintPage(object sender, PrintPageEventArgs e)
{
    foreach(Control control in _GbFrm.Controls)
        DrawControls(control, e.Graphics);
}
private void DrawControls(Control control,Graphics g)
{
    var font = new Font("Arial", 10);
    var brush = new SolidBrush(Color.Black);
    var drawFormat = new StringFormat
    {
        FormatFlags = StringFormatFlags.DirectionRightToLeft
    };
    if (control is Label)
    {
        if ((string)control.Tag == "1") //Treated with 1 columns of fields.
        {
            g.DrawString(
                control.Text, font, brush,
                new Rectangle(control.Location.X - 160, control.Location.Y, control.Size.Width + 10, control.Size.Height),
                drawFormat);
        }
        if ((string)control.Tag == "2") //Treated with 2 columns of fields.
        {
            g.DrawString(
                control.Text, font, brush,
                new Rectangle(control.Location.X - 70, control.Location.Y, control.Size.Width + 10, control.Size.Height),
                drawFormat);
        }
        if ((string)control.Tag == "3") //Treated with 3 columns of fields.
        {
            g.DrawString(
                control.Text, font, brush,
                new Rectangle(control.Location.X, control.Location.Y, control.Size.Width + 10, control.Size.Height));
        }
    }
    else if (control is TextBox || control is ComboBox)
    {
        if ((string)control.Tag == "1") //Treated with 1 columns of fields.
        {
            g.DrawRectangle(
                new Pen(Color.Black, 1),
                new Rectangle(control.Location.X - 120, control.Location.Y, control.Size.Width - 40, control.Size.Height));
            g.DrawString(
                control.Text, font, brush,
                new Rectangle(control.Location.X - 120, control.Location.Y, control.Size.Width - 40, control.Size.Height), drawFormat);
        }
        if ((string)control.Tag == "2") //Treated with 2 columns of fields.
        {
            g.DrawRectangle(
                new Pen(Color.Black, 1),
                new Rectangle(control.Location.X - 30, control.Location.Y, control.Size.Width - 40, control.Size.Height));
            g.DrawString(
                control.Text, font, brush,
                new Rectangle(control.Location.X - 30, control.Location.Y, control.Size.Width - 40, control.Size.Height),
                drawFormat);
        }
        if ((string)control.Tag == "3") //Treated with 3 columns of fields.
        {
            g.DrawRectangle(
                new Pen(Color.Black, 1),
                new Rectangle(control.Location.X, control.Location.Y, control.Size.Width, control.Size.Height));
            g.DrawString(
                control.Text, font, brush,
                new Rectangle(control.Location.X, control.Location.Y, control.Size.Width, control.Size.Height), drawFormat);
        }
    }
    else if (control is PictureBox && control.Visible)
    {
        var img = ((PictureBox)control).Image;
        var bitmap = new Bitmap(img,new Size(img.Width,img.Height));
        g.DrawImage(
            bitmap,
            new Rectangle(control.Location.X, control.Location.Y, control.Size.Width, control.Size.Height));
    }
    else if (control is DateTimePicker)
    {
        g.DrawString(
            control.Text, font, brush,
            new Rectangle(control.Location.X, control.Location.Y, control.Size.Width + 10, control.Size.Height));
    }
}

所有打印问题都工作，但有时打印PictureBox会引起Exception，那么我如何解决这个问题?

PrintDocument printDocument1 = new PrintDocument();
printDocument1.PrintPage +=new PrintPageEventHandler(printDocument1_PrintPage);
printDocument1.Print();

private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
    e.Graphics.DrawImage(pic.Image, 0, 0);
}