12.8. Finding the Subclasses of a Type
Problem
You have a type and you need to find out whether it is subclassed anywhere in an assembly.
Solution
Use the
Type.IsSubclassOf
method to test all types within
a given assembly, which determines whether each type is a subclass of
the type specified in the argument to
IsSubClassOf
:
public static ArrayList GetSubClasses(string asmPath, Type baseClassType) { Assembly asm = Assembly.LoadFrom(asmPath); ArrayList subClasses = new ArrayList( ); if (baseClassType != null) { foreach(Type type in asm.GetTypes( )) { if (type.IsSubclassOf(baseClassType)) { subClasses.Add(type); } } } else { throw (new Exception(baseClassType.FullName + " does not exist in assembly " + asmPath)); } return (subClasses);
The GetSubClasses
method accepts an assembly path
string and a second string containing a fully qualified base class
name. This method returns an ArrayList
of Types
representing the subclasses of the type passed to the
baseClass
parameter.
Discussion
The IsSubclassOf
method on the
Type
class allows us to determine whether the
current type is a subclass of the type passed in to this method.
To use this method, you could use the following code:
public static void FindSubclassOfType( ) { Process current = Process.GetCurrentProcess( ); // get the path of the current module string asmPath = current.MainModule.FileName; Type type = Type.GetType("CSharpRecipes.Reflection+BaseOverrides"); ArrayList subClasses = GetSubClasses(asmPath,type); // write out the subclasses ...
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