Unable to add FileInfo.Name items from string[] to a List field

Question

I have the following method, which is meant to add file names to a List<string> so that the desired order of the files is stored in the Program class:

    private static void ConvertPdfs()
    {
        // Get the word files FileInfo
        FileInfo[] wordFileInfo = DataGrabber.GetHrWordFileInfo(sourceFolder, spSite, policyListName, sortBy);

        foreach (FileInfo file in wordFileInfo)
        {
            // Create the ordered list - this adds each document to the list in the correct oder (sort in CAML query)
            orderedListOfFileNames.Add(file.Name);                
        }           
        Converter convert = new Converter();
        convert.ToPdf(wordFileInfo, targetPdf);
    }

Where ordereListOfFileNames is a field in that same class:

 private static List<string> orderedListOfFileNames; // Stil static ...

When the method loops around wordFileInfo, I am seeing this exception:

An unhandled exception of type 'System.NullReferenceException' Occurred in PdfConverter.exe
Additional information: Object reference not set to an instance of an object.

However, I can see that wordFileInfo contains 22 items, all of which have a name.

Is the issue here the fact that orderedListOfFileNames has not been initialised properly?

[What is a `NullReferenceException` and how do I fix it?](http://stackoverflow.com/q/4660142/447156) — Soner Gönül, Jan 19 '16 at 09:45
How many elements does wordFileInfo have? Maybe an element of wordFileInfo is null? — BitExodus, Jan 19 '16 at 09:52
Can you show the code of "ToPdf" function? I think that the error is on PDFConverter input parameter — bdn02, Jan 19 '16 at 09:53
After properly instantiating the `orderedListOfFileNames` field, the error disappeared (see un-lucky's answer). — Bassie, Jan 19 '16 at 10:00
How could "orderedListOfFileNames" contain 22 items without been initialized? Was it initialized at some other point? — BitExodus, Jan 19 '16 at 10:02

score 3 · Accepted Answer · answered Jan 19 '16 at 09:46

3

You need to instantiate the orderedListOfFileNames before adding value to the list using a new operotor as like the following:

private static List<string> orderedListOfFileNames= new List<string>();

answered Jan 19 '16 at 09:46

sujith karivelil

28,671
6
55
88

score 2 · Answer 2 · edited Feb 23 '16 at 02:56

2

instantiate is not necessary when you are doing the following so thats not the issue.

FileInfo[] wordFileInfo = DataGrabber.GetHrWordFileInfo(sourceFolder, spSite, policyListName, sortBy);

But still when you do the above code wordFileInfo becomes null, so DataGrabber.GetHrWordFileInfo(sourceFolder, spSite, policyListName, sortB) something happends here.

edited Feb 23 '16 at 02:56

sujith karivelil

28,671
6
55
88

answered Jan 19 '16 at 09:53

Hanna

21
1

Unable to add FileInfo.Name items from string[] to a List field

2 Answers2