table null value error

I'm getting the following error when executing the below code when the value of the table entry is null. How do I read a null value?

ArgumentException was unhandled
{"Argument 'Prompt' cannot be converted to type 'String'."}

MsgBox(DataGridView1.Item(1, 1).Value)

As I was going up the stair
I met a man who wasn't there
He wasn't there again today
Oh how I wish he'd go away!

You do understand what 'null' means, right?

If the data came from a database then each null field contains a DBNull object. If all you're doing is displaying the value then you can just call ToString, because DBNull.ToString will yield an empty string, which is appropriate to display for NULL. If you actually want to distinguish between NULL and an actual empty string then you'll need to test whether the value 'Is DBNull.Value' first.