Whenever I try to import an FTA diagram from my Diagram Library into a system file, I get the error "Object reference not set to an instance of an object". I have searched the reference guide and haven't found any mention of this particular error. I know it's also a general Windows error, so a Google search wasn't helpful, either.
Does anyone know what is causing this error? I can provide more details if need be.
Solved! Go to Solution.
An Object is an instance of a Class , it is stored some where in memory. A reference is what is used to describe the pointer to the memory location where the Object resides. The message "object reference not set to an instance of an object" means that you are referring to an object the does not exist or was deleted or cleaned up. It's usually better to avoid a NullReferenceException than to handle it after it occurs. To prevent the error, objects that could be null should be tested before being used.
if (mClass != null)
// Go ahead and use mClass
mClass.property = ...
// Attempting to use mClass here will result in NullReferenceException
A NullReferenceException typically reflects developer error and is thrown in the following scenarios: