I can't explain it properly in the subject section, it's not as simple as that. Here is the code snippet in question.

UserPass = reader["Password"].ToString();

So UserPass is my string variable and reader is an SqlReader object. Here is it being instantiated:

SqlDataReader reader = myCommand.ExecuteReader();

(myCommand is an SqlCommand obj)

reader["Password"]

Password is a column name in my Sql DB. Basically I've just told the reader to go look within that column and used a query to specify where abouts. I want to set the reader["Password"] equal to an empty string to compare against user input. Now there aren't any errors when I do this but it does throw an exception:

An exception of type 'System.InvalidOperationException' occurred in System.Data.dll but was not handled in user code

It doesn't give much more detail other than that and I'm not entirely sure what's wrong.