NPOI datagridatagriexport EXCEL

NPOI official website http://npoi.codeplex.com/load NPOI. DLL, reference these two namespaces

Using NPOI. HSSF. UserModel;
Using NPOI. SS. UserModel;

# Region NPOI datagridatagriexport EXCEL /// <summary> // NPOI DataGridView export EXCEL /// </summary> /// <param name = "fileName"> Save the file name by default </param> /// <param name = "dgv"> DataGridView </param> /// <param name = "fontname"> fontname </param> /// <param name = "fontsize"> font size </param> public void ExportExcel (string fileName, dataGridView dgv, string fontname, short fontsize) {// checks whether data exists if (dgv. selectedRows. count = 0) re Turn; // create the main object HSSFWorkbook workbook = new HSSFWorkbook (); HSSFSheet sheet = (HSSFSheet) workbook. createSheet ("Weight"); // you can specify the font, size, and alignment of HSSFCellStyle = (HSSFCellStyle) workbook. createCellStyle (); HSSFFont font = (HSSFFont) workbook. createFont (); font. fontName = fontname; font. fontHeightInPoints = fontsize; style. setFont (font); style. alignment = NPOI. SS. userModel. horizontalAlignment. center; // Center Align // Add the header HSSFRow dataRow = (HSSFRow) sheet. createRow (0); for (int I = 0; I <dgv. columns. count; I ++) {dataRow. createCell (I ). setCellValue (dgv. columns [I]. headerText); dataRow. getCell (I ). cellStyle = style;} // This line of comment is set to filter // sheet. setAutoFilter (new CellRangeAddress (0, dgv. columns. count, 0, dgv. columns. count); // Add columns and content for (int I = 0; I <dgv. rows. count; I ++) {dataRow = (HSSFRow) sheet. createRow (I + 1); for (int j = 0; j <dgv. columns. count; j ++) {string ValueType = dgv. rows [I]. cells [j]. value. getType (). toString (); string Value = dgv. rows [I]. cells [j]. value. toString (); switch (ValueType) {case "System. string ": // String type dataRow. createCell (j ). setCellValue (Value); break; case "System. dateTime ": // Date type System. dateTime dateV; System. dateTime. tryParse (Value, out dateV); dataRow. createCell (j ). setCellVa Lue (dateV); break; case "System. boolean ": // Boolean bool boolV = false; bool. tryParse (Value, out boolV); dataRow. createCell (j ). setCellValue (boolV); break; case "System. int16 ": // integer case" System. int32 ": case" System. int64 ": case" System. byte ": int intV = 0; int. tryParse (Value, out intV); dataRow. createCell (j ). setCellValue (intV); break; case "System. decimal ": // floating case" System. double ": double doubV = 0; d Ouble. tryParse (Value, out doubV); dataRow. createCell (j ). setCellValue (doubV); break; case "System. DBNull ": // processing dataRow for null values. createCell (j ). setCellValue (""); break; default: dataRow. createCell (j ). setCellValue (""); break;} dataRow. getCell (j ). cellStyle = style; // set the width of sheet. setColumnWidth (j, (Value. length + 10) * 256) ;}// save the file string saveFileName = ""; SaveFileDialog saveDialog = new SaveFileDialog (); SaveDialog. defaultExt = "xls"; saveDialog. filter = "Excel file | *. xls "; saveDialog. fileName = fileName; MemoryStream MS = new MemoryStream (); if (saveDialog. showDialog () = DialogResult. OK) {saveFileName = saveDialog. fileName; if (! CheckFiles (saveFileName) {MessageBox. show ("the file is used. close the file" + saveFileName); workbook = null; ms. close (); ms. dispose (); return;} workbook. write (MS); FileStream file = new FileStream (saveFileName, FileMode. create); workbook. write (file); file. close (); workbook = null; ms. close (); ms. dispose (); MessageBox. show (fileName + "saved successfully", "prompt", MessageBoxButtons. OK);} else {workbook = null; ms. close (); ms. di Spose () ;}# endregion # region detection file occupied [DllImport ("kernel32.dll")] public static extern IntPtr _ lopen (string lpPathName, int iReadWrite ); [DllImport ("kernel32.dll")] public static extern bool CloseHandle (IntPtr hObject); public const int OF_READWRITE = 2; public const int OF_SHARE_DENY_NONE = 0x40; public readonly IntPtr HFILE_ERROR = new IntPtr (-1); // <summary> // check if the file is occupied /// </summary> /// <Param name = "FileNames"> file path to be detected </param> // <returns> </returns> public bool CheckFiles (string FileNames) {if (! File. exists (FileNames) {// return true if the file does not exist;} IntPtr vHandle = _ lopen (FileNames, OF_READWRITE | OF_SHARE_DENY_NONE); if (vHandle = HFILE_ERROR) {// return false;} // CloseHandle (vHandle); return true;} # endregion

The specific effect is as follows: