helper-NPOIwrap-use-Excel-xlsx 1.0.3

THIS DLL IS AVAILABLE AS NUGET-PACKAGE 'helper-NPOIwrap-use-Excel-xlsx.1.0.2.nupkg'

1. my motivation

Seeing NPOI and using it is great. Usage for my own software is reading and writing data from/to real Excel files.
To wrap NPOI there are just a few use cases that need to be cared for if you listen to NPOI's creator and your own view about the data I/O.
There are just 3 kinds of cells used: 'string', 'numeric' and 'function' - while i don't need 'function'.
Concerning that i analysed the lines: there are special ones ( 'mixed' ) and the general list types ( 'string', 'double' ). For both cases you can use the given classes:

• ExcelDataRow: the mixed special version only as example. You would create your own data mixture in that way.
• ExcelDataRowListString/-Double: the list type having only one celltype in the row

Value is not in empty cells on the program side - but you buffer in whole blocks of data. You can use header lines to mark your data in your own logic.

2. Procedure:

I added functions to get and to give data to the wrapper ( <u>DataList...As...(), Array...ToDataList...()</u> ). In the program you take an instance of the '<u>NPOIexcel</u>'-class and everything is wrapped.

To read from an Excel-file:

• NPOIexcel myData = new NPOIexcel(); // the wrapper for NPOI
• myData.ReadWorkbook(); // this will give you the file dialog
• myData.ReadSheets(); // first overview of the given file for the workbook
• myData.ReadSheetAsListDouble( 0 ); // sheetNumber = 0, no header used, filled into dataListDouble
• double[][] doubles = myData.DataListDoubleAsArrayRagged(); // there you have your Excel's file data to your convenience

You should add data from the program side into the lists and then write the file:

• myData.CreateWorkbook(); // start empty
• myData.CreateSheet( 0 ); // new sheet to be filled
• myData.ArrayRaggedToDataListDouble( doubles ); // you give him your data
• myData.CreateSheetFromListDouble( 0 ); // this adds the data now to the workbook
• myData.SaveWorkbook( fileName ); // this will save the file in real excel format thanks to NPOI

I use lists to handle the workbook's possible complexity. They will be instanciated with standard values and later with the special operation of reading sheet# you can get your real headers, too.

• myData.ReadSheetAsListDouble( 0, true ); // sheetNumber = 0, header used, filled into dataListDouble
• string[] headers = myData.GetHeaderNo( 0 ); // sheetNumber = 0

3. Demoprogram

Demoprogram for the DLL is: WPFwithNPOI. It shows how easy you can read and write Excel-xlsx-files. Every menuitem uses its local version of the NPOIexcel-class and thus works as complete example about how-to-use the NPOIwrap on your own.

This helper class uses NPOI by
<u>Author: Tony Qu,NPOI Contributors</u>