How to change Application in app.xml (XSSF) with NPOI?

Question

Unzipping an .xlsx generated with NPOI I noticed that NPOI set itself as "Application" in docProps/app.xml and also added "Generator" to docProps/custom.xml.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Properties xmlns="http://schemas.openxmlformats.org/officeDocument/2006/extended-properties" xmlns:vt="http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes">
    <Application>NPOI</Application>
    <AppVersion>123.456</AppVersion>
</Properties>

How do I edit the Application information in app.xml?

I only found CoreProperties, CustomProperties and ExtendedProperties, but nothing called "AppProperties".

Answer 1

You need to get the underlying properties from the ExtendedProperties and then set the Application property of that. The following example sets the Application and AppVersion:

static void Main(string[] args)
{
    XSSFWorkbook workbook = new XSSFWorkbook();
    ISheet sheet1 = workbook.CreateSheet("Sheet1");

    POIXMLProperties props = workbook.GetProperties();

    //get the underlying properties (of type NPOI.OpenXmlFormats.CT_ExtendedProperties)
    var underlyingProps = props.ExtendedProperties.GetUnderlyingProperties();
    //now set the properties (excuse the vanity!)
    underlyingProps.Application = "petelids";
    underlyingProps.AppVersion = "1.0";

    FileStream sw = File.Create("test.xlsx");
    workbook.Write(sw);
    sw.Close();
}

Generator properties

Example of changing the Generator in CustomProperties (custom.xml).

CustomProperties customProperties = properies.CustomProperties;
customProperties.AddProperty("Generator", "petelids");
customProperties.AddProperty("Generator Version", "1.0");