合并两个WORD文档，并且修改Word中标签的内容

因工作需要，需要对两个word 文档进行合并

 Word.Application objApp=new Word.ApplicationClass();
            object confirmConversion = false;
            object link = false;
            object attachment = false;
            object objMissing = Missing.Value;
            object isVisible = true;
            object objFalse = false;  
            try
            {
               
                Word.Document objDoc = null;
                objDoc = objApp.Documents.Open(
                 ref objOrgDoc,    //FileName
                 ref objMissing,   //ConfirmVersions
                 ref objMissing,   //ReadOnly
                 ref objMissing,   //AddToRecentFiles
                 ref objMissing,   //PasswordDocument
                 ref objMissing,   //PasswordTemplate
                 ref objMissing,   //Revert
                 ref objMissing,   //WritePasswordDocument
                 ref objMissing,   //WritePasswordTemplate
                 ref objMissing,   //Format
                 ref objMissing,   //Enconding
                 ref objMissing,   //Visible
                 ref objMissing,   //OpenAndRepair
                 ref objMissing,   //DocumentDirection
                 ref objMissing,   //NoEncodingDialog
                 ref objMissing    //XMLTransform
                 );
               
                if (objDoc.Bookmarks.Exists((string)bm_ReceiveOrderNo))
                    ReplaceBookMark(objDoc, bm_ReceiveOrderNo, receiveOrderNo, 32);
                if (objDoc.Bookmarks.Exists((string)bm_CertNo))
                    ReplaceBookMark(objDoc, bm_CertNo, certNo, 32);
                if (objDoc.Bookmarks.Exists((string)bm_VerifiedUnit))
                    ReplaceBookMark(objDoc, bm_VerifiedUnit, verifiedUnit, 55);
                if (objDoc.Bookmarks.Exists((string)bm_Name))
                    ReplaceBookMark(objDoc, bm_Name, name, 55);
                if (objDoc.Bookmarks.Exists((string)bm_Specification))
                    ReplaceBookMark(objDoc, bm_Specification, specification, 55);
                if (objDoc.Bookmarks.Exists((string)bm_Rank))
                    ReplaceBookMark(objDoc, bm_Rank, rank, 55);
                if (objDoc.Bookmarks.Exists((string)bm_ProductionCode))
                    ReplaceBookMark(objDoc, bm_ProductionCode, productionCode, 55);
                if (objDoc.Bookmarks.Exists((string)bm_ProductionUnit))
                    ReplaceBookMark(objDoc, bm_ProductionUnit, producteUnit, 55);
                if (objDoc.Bookmarks.Exists((string)bm_ReasonBase))
                    ReplaceBookMark(objDoc, bm_ReasonBase, reasonBase, 55);
                if (objDoc.Bookmarks.Exists((string)bm_Conclusion))
                    ReplaceBookMark(objDoc, bm_Conclusion, conclusion, 55);
              
                if (objDoc.Bookmarks.Exists((string)bm_VerifyDate))
                    objDoc.Bookmarks.get_Item(ref bm_VerifyDate).Range.Text = verifyDate;
                if (objDoc.Bookmarks.Exists((string)bm_ExpireDate))
                    objDoc.Bookmarks.get_Item(ref bm_ExpireDate).Range.Text = expireDate;

                Range r = objDoc.Range(ref objMissing,ref objMissing);
                object direction = Word.WdCollapseDirection.wdCollapseEnd;
                r.Collapse(ref direction);
                object objBreak = WdBreakType.wdSectionBreakNextPage;
                r.InsertBreak(ref objBreak);
                r.InsertFile(this.txtFilePath.Text, ref objMissing, ref confirmConversion, ref link, ref attachment);
               
                object objOutDoc = path;
                objDoc.SaveAs(ref objOutDoc,
                          ref objMissing,     //FileFormat
                          ref objMissing,     //LockComments
                          ref objMissing,     //PassWord     
                          ref objMissing,     //AddToRecentFiles
                          ref objMissing,     //WritePassword
                          ref objMissing,     //ReadOnlyRecommended
                          ref objMissing,     //EmbedTrueTypeFonts
                          ref objMissing,     //SaveNativePictureFormat
                          ref objMissing,     //SaveFormsData
                          ref objMissing,     //SaveAsAOCELetter,
                          ref objMissing,     //Encoding
                          ref objMissing,     //InsertLineBreaks
                          ref objMissing,     //AllowSubstitutions
                          ref objMissing,     //LineEnding
                          ref objMissing      //AddBiDiMarks
                          );
                return path;
            }
           finally
            {
                objApp.Quit(ref objFalse,
                 ref objMissing,
                 ref objMissing
                 );
                objApp = null;
            }

 private void ReplaceBookMark(Document doc, object bookmarkName, string text, int CharLength)
        {
            Range rng = doc.Bookmarks.get_Item(ref bookmarkName).Range;
            rng.Text = text;
            int count = System.Text.Encoding.GetEncoding("gb2312").GetBytes(text).Length;
           
            if (CharLength > count)
            {
                int startAddedSpaceCount = (CharLength - count) / 2;
                int endAddedSpaceCount = (CharLength - count) / 2 + (CharLength - count) % 2;
                rng.InsertBefore(GetSpaceString(startAddedSpaceCount));
                rng.InsertAfter(GetSpaceString(endAddedSpaceCount));
                rng.Font.Underline = WdUnderline.wdUnderlineSingle;
             
            } 
        }

        private string GetSpaceString(int StringLength)
        {
            StringBuilder sb = new StringBuilder();
            for(int i=0;i<StringLength;i++)
            {
                sb.Append(" ");
            }
            return sb.ToString();
        }