When would SqlCommand.ExecuteReader() return null?

Question

When using calling the SqlCommand.ExecuteReader() method, ReSharper tells me I have a possible NullReference exception when I use the SqlDataReader object after

Answer 1

I have determined one reason why ExecuteReader() can return null.

In the case where I was getting a null, I had sent my client a script to update a stored procedure. My client's Sql Server (2000) is set up so that DB users need a permission to execute a stored procedure. When they updated the SP the permission was removed and not re-assigned. In this instance the SqlCommand.ExecuteReader() returned a null.

Re-assigning the permission fixed this.