如何打印一张位图图片

    public partial class frmPrint : DevExpress.XtraEditors.XtraForm
    {
        Bitmap myPic;
        bool landscape=false;
        //构造函数
        public frmPrint(string mypic)
        {
            InitializeComponent();
            myPic = new Bitmap(mypic);
            this.pictureEdit1.Image = myPic;
        }
        //打印时绘图
        private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
        {
            e.Graphics.DrawImage(myPic, 0, 0);
        }
        //关闭
        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            this.Close();
        }
        //打印
        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            PrintDialog MyPrintDg = new PrintDialog();
            MyPrintDg.Document = printDocument1;

            if(landscape)
                printDocument1.DefaultPageSettings.Landscape = true;
            else
                printDocument1.DefaultPageSettings.Landscape = false;

            if (MyPrintDg.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    printDocument1.Print();
                }
                catch
                {   //停止打印
                    printDocument1.PrintController.OnEndPrint(printDocument1, new System.Drawing.Printing.PrintEventArgs());
                }
            }
        }
        //是否横板打印
        private void toolStripCheckBox1_CheckedChanged(object sender, EventArgs e)
        {
            landscape = !landscape;
        }
        //窗体即将关闭
        private void frmPrint_FormClosing(object sender, FormClosingEventArgs e)
        {
            pictureEdit1.Dispose();
            myPic.Dispose();
            Directory.SetCurrentDirectory(Application.StartupPath);
            if (Directory.Exists(Application.StartupPath + "\\tmpbmp"))
            {
                Directory.Delete(Application.StartupPath + "\\tmpbmp", true);
            }
            e.Cancel = false;
        }
    }