Will GetType() return the most derived type when called from the base class?
Solution 1
GetType()
will return the actual, instantiated type. In your case, if you call GetType()
on an instance of B
, it will return typeof(B)
, even if the variable in question is declared as a reference to an A
.
There is no reason for your GetSubType()
method.
Solution 2
GetType
always returns the type that was actually instantiated. i.e. the most derived type. This means your GetSubType
behaves just like GetType
itself and thus is unnecessary.
To statically get the type information of some type you can use typeof(MyClass)
.
Your code has a mistake though: System.Attribute.GetCustomAttributes
returns Attribute[]
not Type
.
Solution 3
GetType always returns the actual type.
The reason for it is deep in the .NET framework and CLR, as the JIT and CLR use the .GetType
method to create a Type object in memory that holds the information on the object, and all access to the object and compilation are via this Type instance.
For more information, take a look in the book "CLR via C#" from Microsoft Press.
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Matthew Cox
Professional software engineer since 2010 building web applications.
Updated on April 09, 2020Comments
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Matthew Cox about 4 years
Will GetType() return the most derived type when called from the base class?
Example:
public abstract class A { private Type GetInfo() { return System.Attribute.GetCustomAttributes(this.GetType()); } } public class B : A { //Fields here have some custom attributes added to them }
Or should I just make an abstract method that the derived classes will have to implement like the following?
public abstract class A { protected abstract Type GetSubType(); private Type GetInfo() { return System.Attribute.GetCustomAttributes(GetSubType()); } } public class B : A { //Fields here have some custom attributes added to them protected Type GetSubType() { return GetType(); } }
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Admin almost 6 yearsDoes it though? I am passing an instance of an object from its (abstract) super class, the receiver only sees the super class. Is it not that it will always return what the handle was defined as not the instance? - or am i missing something?
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Admin almost 6 yearsAh ha.. the difference is using TypeOf(X) vs. x.GetType() i think