Generic coverter for fields in class
referenceRow.field



The field name does not comply with the C# naming convention for public members that should be PascalCase. It should also probably be Fields since it's apparently a collection.




typeActions



Consider changing its name to convertTo which in this context makes the usage more natural:

var fieldValue = convertTo[typeof(T)]();





Func&lt;object&gt;



Consider using a parameter rahter then using closures. That makes the usage even clearer.

If you define it as

Func&lt;object, object&gt;


and the lambdas as

{ typeof(DateTime), x =&gt; { return DateTime.Parse(x.ToString()); } },


you can call it with

var fieldValue = convertTo[typeof(T)](referenceField.Item);





if (referenceField != null)



Avoid unnecessary nesting. You can use a postive condition == null and return right away if it's nulll.




return (T)Convert.ChangeType(fieldValue, typeof(T));



This is redundant. The converted value has already the target type. It just needs to be casted and because the ChangeType boxes the value anyway, you might as well do it yourself like this:

return (T)(object)typeActions[typeof(T)]();