List with several results in it needs to go to another list for output to csv

Question

I have one list that is called SearchResult the model for it looks like this:

public class Wrapper
{
   public Wrapper()
   {
      Columns = new List<SearchColumn>();
      Rows = new List<SearchRow>()
   }

   public long Total { get; set; } = 0;
   public double Milliseconds { get; set; }
   public List<SearchColumn> Columns { get; set; }
   public List<SearchRow> Rows { get; set; }
}

I use this in a method to attempt to return the result set and export it to a csv file like this:

 private Wrapper SearchResult { get; set; } = new();

public async Task<DownloadFile> StartExport()
{
    //code removed for brevity
    var searchComp = 10000;
    var fileName = "SearchResults";
    var records = SearchResult.Rows.ToList();

    if (defaultValue <= searchComp)
    {
        await Task.Yield();
        return fileEx.ExportToCsv(records, fileName);
    }
    
}

This builds and runs in the application but still does not produce a csv file with the information on it.

The error that I get is "System.NullReferenceException: Object reference not set to an instance of an object"

At this line:

 return fileEx.ExportToCsv(records, fileName);

I assumed it was the "records" returning null however when I debugged the code records had information in it.

So why wouldn't it produce the csv file? I also debugged the ExportToCsv method with a file I knew worked and it worked as expected.

This should return: ID, Name, DOB... in a csv file.

What should I do to remedy the error I am getting?