Checking if an object is null in C#

Question

I would like to prevent further processing on an object if it is null.

In the following code I check if the object is null by either:

if (!data.Equal         


        

Answer 1

Jeffrey L Whitledge is right. Your `dataList´-Object itself is null.

There is also another problem with your code: You are using the ref-keyword, which means the argument data cannot be null! The MSDN says:

An argument passed to a ref parameter must first be initialized. This differs from out, whose arguments do not have to be explicitly initialized before they are passed

It's also not a good idea to use generics with the type `Object´. Generics should avoid boxing/unboxing and also ensure type safety. If you want a common type make your method generic. Finally your code should look like this:

public class Foo where T : MyTypeOrInterface {

      public List dataList = new List();

      public bool AddData(ref T data) {
        bool success = false;
        try {
          dataList.Add(data);                   
          success = doOtherStuff(data);
        } catch (Exception e) {
          throw new Exception(e.ToString());
        }
        return success;
      }

      private bool doOtherStuff(T data) {
        //...
      }
    }