Is Streamreader reading a line that doesn’t exist?

Question

I want to read a CSV file and save it in a table, but for some reason it still gives the following error:

System.Nullreferenceexception: 'Object Reference not set to an instance of an Object.'

line was null.

I already ran the debug and noticed that it is reading a line that does not exist, for example, reaches line 194 with x values (supposedly the last line of the file and then reads another line (195) that does not exist and does not have any kind of values (null). I tried to fix it by opening the CSV file with Notepad and I checked that there was an extra line with nothing and deleted and saved and after this it should work and is not.

Here is my code:

using (StreamReader sr = new streamReader(@"PATH"))
{
   var datatable = new DataTable();
   datatable.Columns.Add("PowerPlantId", typeof(string));
   datatable.Columns.Add("AssetId", typeof(int));
   string line;

   line = sr.ReadLine();
   if (line != null)
   {
      do
      {
         line = sr.ReadLine();
         System.Diagnostics.Debug.WriteLine(line + "\n");
         string[] lineitems = line.Split(",");
         DataRow dr = datatable.NewRow();
         dr["PowerPlantId"] = lineitems[0];
         dr["AssetId"] = lineitems[1];
         datatable.Rows.Add(dr);
      } while (line != null);
   }

Answer 1

What is happening is that you are trying to do all the operations on the line to then check if it is null, which doesn’t make much sense.

That should work:

string line;

while ((line = sr.ReadLine()) != null) //Lê a linha e já checa se ela é nula
{
    // demais operações
}