public partial class Print : Form
    {

       // 定義dgSetPage托付進行打印時的選項設置
        public delegate void dgSetPage();   

       //定義dgFiledelete 托付進行打印完畢后。刪除填充后的模板文件
        public delegate void dgFiledelete();

        [DllImport("User32.dll", EntryPoint = "FindWindow")]
        private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
        [DllImport("User32.dll", EntryPoint = "FindWindowEx")]
        private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpClassName, string lpWindowName);
 
        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, int lParam);

        //定義SendMessage方法內使用的鼠標單擊 常量

        const int BM_CLICK = 0xF5;

        private void btnPrint_Click(object sender, EventArgs e)
        {
            btnPrint.Enabled = false;

           //由于是使用WebBrowser對象進行打印HTML文件，所以無法控制頁面設置，須要使用注冊表改動一些內容

           //方法 ChangePageSettingByRegist 。改動注冊表，取消頁眉、頁角項目
            ChangePageSettingByRegist();

           //讀取數據填充HTML模板
            string sFillDataResult=FillDataToNewFile();

            if (sFillDataResult.IndexOf("NG") >= 0)
            {
                MessageBox.Show(sFillDataResult);
                return;
            }

            pd_PrintPage(); 
            btnPrint.Enabled = true;
        }

        private void pd_PrintPage()
        {
            //創建一個WebBrowser對象，然后用它在后臺打開并解釋HTML文件
            WebBrowser webBrowserForPrinting = new WebBrowser();

           //  lblNewFile.Text  保存是填充后的模板文件名稱 
            webBrowserForPrinting.Url = new Uri(Application.StartupPath.ToString() + "\\" +  lblNewFile.Text);

            //當載入文件完畢后激發手動追加的事件
            webBrowserForPrinting.DocumentCompleted +=   new WebBrowserDocumentCompletedEventHandler(PrintDocument);
            webBrowserForPrinting.Focus();
        }

        private void PrintDocument(object sender,WebBrowserDocumentCompletedEventArgs e)
        { 
            //創建一個新的線程，用于當彈出頁面設置對話框時發送設置為橫向的指令
            Thread th = new Thread(new ThreadStart(new dgSetPage(SetPage)));
            th.Start(); 

            //彈出頁面設置對話框-----即上方定義的新進程須要處理的窗體
            ((WebBrowser)sender).ShowPageSetupDialog();

            //打印
            ((WebBrowser)sender).Print();
           
            //釋放資源
            ((WebBrowser)sender).Dispose();

            //刪除填充后的模板文件，防止反復打印
            System.IO.File.delete(lblNewFile.Text);
            lblNewFile.Text = "";
        }

        //  此處方式被凝視掉了，由于假設須要改動主窗體內控件的內容或者狀況里須要使用托付調用改動方法

       //  須要時，把SetPage與SetPage2名稱互換就可以在變更后的名稱為SetPage2內加入改動主窗體內容的代碼
        //private void SetPage2()
        //{
        //    //新建托付對象
        //    MethodInvoker In = new MethodInvoker(SetPage2);
        //    this.BeginInvoke(In);
        //}

        private void SetPage()
        {
            int i = 0;

          //      此處須要設置循環查找時間。眼下為超過10秒未找到結束查找
          while (true)
            {
                IntPtr WindownHand = FindWindow("#32770", "頁面設置");
                if (WindownHand != IntPtr.Zero)
                {

                    //找到窗體內子項目的名柄，然后模擬鼠標左鍵單擊事件
                    IntPtr Wk = FindWindowEx(WindownHand, IntPtr.Zero, null, "橫向(&A)");
                    SendMessage(Wk, BM_CLICK, 0, 0);

                    IntPtr Wk1 = FindWindowEx(WindownHand, IntPtr.Zero, null, "確定");
                    SendMessage(Wk1, BM_CLICK, 0, 0);

                    break;
                }
                else
                {
                    if (i > 20)
                        break;
                    Thread.Sleep(500);
                    i++;
                }
            }

        }

        //改動注冊表，把頁眉頁腳拿掉。然后設置為縮放至一頁
        private void ChangePageSettingByRegist()
        {
            RegistryKey hklm = Registry.CurrentUser;
            RegistryKey software = hklm.OpenSubKey(@"Software\Microsoft\Internet Explorer\PageSetup".ToUpper(), true);
            object A = (object)"";
            object B = (object)"0.5";
            object C = (object)"0";
            software.SetValue("header", A);
            software.SetValue("footer", A);
            software.SetValue("margin_bottom", B);
            software.SetValue("margin_left", C);
            software.SetValue("margin_right", C);
            software.SetValue("margin_top", C);
            software.SetValue("Shrink_To_Fit","yes");          

        }

HTML模板內容片段

     <%A%>  占位符，用于替換

    <table cellpadding="0" cellspacing="0" border="0px">
        <tr><td colspan="8"  class="EachPartSpace"></td></tr>
        <tr><td class="LayOutFieldTitle" colspan="8">Machine Protocol</td></tr>       
        <tr>
            <td class="FieldNameHorizontal Column1With">Purchase Order No:</td>
            <td class="FieldValueHorizontal Column2With"><%OrderNo%></td>
            <td class="FieldNameHorizontal Column1With">Unit No:</td>
            <td class="FieldValueHorizontal Column2With"><%UnitNo%></td>
            <td class="FieldNameHorizontal Column1With">Region:</td>
            <td class="FieldValueHorizontal Column6With"><%Region%></td>
            <td class="FieldNameHorizontal Column2With">Assembly date:</td>
            <td class="FieldValueHorizontal Column2With"><%AssemblyDate%></td>
        </tr>
    </table>