Exporting a CSV file using Npoi import in C #

1. First (download DLL Npoi official website)

Add Reference:NPOI.dll,npoi. OOXML.dll,npoi. OpenXml4Net.dll,npoi. OpenXmlFormats.dll

2. Code--csvhelper

1      Public classCsvhelper2     {3         /// <summary>4         ///Write to CSV5         /// </summary>6         /// <param name= "FileName" >file name</param>7         /// <param name= "DT" >the DataTable to write to</param>8          Public Static voidWritecsv (stringfilename,datatable DT)9         {Ten FileStream FS; One StreamWriter SW; A             stringdata =NULL; -  -             //determines whether the file exists, does not write the column name again the             if(!file.exists (fileName)) -             { -FS =NewFileStream (FileName, FileMode.Create, FileAccess.Write); -SW =NewStreamWriter (FS, Encoding.UTF8); +  -                 //write out the column name +                  for(inti =0; i < dt. Columns.count; i++) A                 { atData + =dt. Columns[i]. Columnname.tostring (); -                     if(I < dt. Columns.count-1) -                     { -Data + =",";//in the middle, separated -                     } -                 } in SW. WriteLine (data); -             } to             Else +             { -FS =NewFileStream (FileName, Filemode.append, FileAccess.Write); theSW =NewStreamWriter (FS, Encoding.UTF8); *             } $             Panax Notoginseng             //write each row of data -              for(inti =0; i < dt. Rows.Count; i++) the             { +data =NULL; A                  for(intj =0; J < dt. Columns.count; J + +) the                 { +Data + =dt. ROWS[I][J]. ToString (); -                     if(J < dt. Columns.count-1) $                     { $Data + =",";//in the middle, separated -                     } -                 } the SW. WriteLine (data); -             } Wuyi SW. Close (); the FS. Close ();  -         } Wu  -  About  $         /// <summary> -         ///Read CSV file -         /// </summary> -         /// <param name= "FileName" >file path</param> A          Public StaticDataTable Readcsv (stringfileName) +         { theDataTable dt =NewDataTable (); -FileStream fs =NewFileStream (FileName, FileMode.Open, FileAccess.Read); $StreamReader sr =NewStreamReader (FS, Encoding.UTF8); the  the             //record a row of records per read the             stringStrLine =NULL; the             //record the contents of each field in each row of records -             string[] arrayline=NULL; in             //Separators the             string[] separators = {"," }; the             //judge, if for the first time, create a table header About             BOOLIsFirst =true; the  the             //Read the CSV file line by row the              while((StrLine = Sr.) ReadLine ())! =NULL) +             { -StrLine = Strline.trim ();//Remove Kinsoku spaces theArrayline = Strline.split (separators, stringsplitoptions.removeemptyentries);//separating strings, returning arraysBayi                 intDtcolumns = Arrayline.length;//Number of columns the  the                 if(IsFirst)//Create a table header -                 { -                      for(inti =0; i < dtcolumns; i++) the                     { theDt. Columns.Add (Arrayline[i]);//each column name the                     } the                 } -                 Else   //Table Content the                 { theDataRow datarow = dt. NewRow ();//New Row the                      for(intj =0; J < Dtcolumns; J + +)94                     { theDATAROW[J] =Arrayline[j]; the                     } theDt. Rows.Add (DataRow);//Add a row98                 } About             } - Sr. Close ();101 FS. Close ();102 103             returnDT;104}

Exporting a CSV file using Npoi import in C #