Question

In my program, I’m looping through a datatable to get data from each field. One line of my code looks like this:

int LYSMKWh = Convert.ToInt32(resultsDT.Rows[currentRow]["LYSMKWh"]);

Basically, I’m just taking the value that’s in the cell and converting it to an int32. I run into a problem, though, when the data in the field is a null. I get an Invalid Cast error message about not being able to convert a “DBNull” to another type.

So, I know that I can just check the value of the field before I try to convert it by doing something like this:

if (resultsDT.Rows[currentRow]["LYSMKWh"] == null)
            {
                resultsDT.Rows[currentRow]["LYSMKWh"] = 0;
            }

But, is there a better way to do this? Is there something I can do “inline” while I’m trying to convert the value without having to resort to using the if ?

EDIT: I did try using this suggested method:

int LYSMKWh = Convert.ToInt32(resultsDT.Rows[currentRow]["LYSMKWh"] ?? "0");

Unfortunately, I still received the Invalid Cast error message with regards to the DBNull type. It was suggested that I could have problems using the ?? operator if the types on either side were different.

Also, since I have complete control over the data that I’m building my datatable with, I changed it so that no null values would be written to any field. So, that pretty much negates the need to convert a null to an int32, in this case. Thanks for all the advice, everyone!

Answer 1

You could do this:

var LYSMKWh =
    resultsDT.Rows[currentRow]["LYSMKWh"].Equals(DBNull.Value)
    ? 0
    : Convert.ToInt32(resultsDT.Rows[currentRow]["LYSMKWh"]);