Cannot perform runtime binding on a null reference exception

Question posted 2011 · +6 upvotes

I’m trying to find the dimensions of an Excel table using C# by finding the first null cell within the first column (which consists of dates) and the header row.

Here’s the code I’m using right now:

public static void findingTableBounds()
    {
        string dateCol = "";
        ArrayList dateColumn = new ArrayList();
        ArrayList numberOfColumns = new ArrayList();

        for (int column = 1; column < currentRow; column++)
        {
            dateCol = ((Excel.Range)workSheet.Cells[currentRow, 1]).Value2.ToString();
            if (dateCol != "")
            {
                dateColumn.Add(dateCol);
                currentRow++;
                totalRow++;
                Console.WriteLine("Total Row: {0}", totalRow);            
            }
            else
            {
                Console.WriteLine("Total Row: {0}", totalRow);
                currentRow = 2;
            }
        }

**Note: There is a closing bracket for this method, I didn’t include it because there’s another for loop that does the exact same thing as the above code but only for how many columns there are.

The error occurs at “dateCol = ((Excel.Range)workSheet.Cells[currentRow, 1]).Value2.ToString();” I’m pretty sure it happens because I’m trying to assign a null value (the cell) to dateCol (a string) when string is a non-nullable type. Unfortunately I’m not sure how to solve the problem.