Check if an object is a type object

[Fredrik Strandberg]

Hi!

I receive an object as a System.Object argument to a method. I need to
check if the object is a Type object or not (that is, not a specific
type, but if the object is a type object in general). How can I do
this? Is there a way of checking if my object inherits from the
System.Type class?

sub myMethod(obj as Object)

if ("obj is a type object")

...do my stuff...

I could not find any solution in any thread in the google groups. I
only find threads about how to determine the Type of an object, but I
need to determine if my object is a Type object!

As far as i understand, I am not able to use the Type.IsInstance OfType
method since the Type class is abstract, i.e.

Type typeObj
typeObj.IsInsta nceOfType(GetTy pe(obj))

does not work.

Thank you for your time!

/Fredrik

[parez]

Hi

This might work

test(GetType(Da taColumn))

Private Sub test(ByVal obj As Object)

MsgBox(obj.GetT ype.ToString)
End Sub

[jvb]

I would recommend

If TypeOf obj is <Type> then
..
ElseIf TypeOf obj is <Type> then.
..
End If

[AlanT]

If you have a routine

Sub fx(obj as object)
end sub

and call it with a type as a parameter

e.g

fx(GetType(Inte ger))

or,

dim str as string = ""
fx(str.GetType( ))
Then the incoming parameter will have a type of

System.RuntimeT ype
The nice way to check would be to compare with that type
if (obj.GetType() is GetType(System. RuntimeType)) then
....
end if

but System.RuntimeT ype is private and not accessible - that's what the
error message says ?

More clumsy, but will work, is to compare with the name

if (obj.GetType(). ToString() = "System.Runtime Type") then
...
end if

will allow you to discern which of the incoming objects are types.
hth,
Alan.

[Fredrik Strandberg]

I may missinterpret your answers but,

parez - I cannot use a msgBox to determine manually if the obejct is a
type object, it has to be done automatically.

jvb - If I understand you correctly <Type> should be replaced with the
types I am looking for, but I am looking for all types. If the method
call to my method is:

myMethod(GetTyp e(anyobject))

then I want to be able to determine that it is a type object that I
receive, in contrast to

Dim obj as MyClass

myMethod(obj)

where the obj (probably) is not a type object.

I do not however have any idea of which types the objects may be!

/Fredrik

[Fabio]

"AlanT" <al*******@user s.com> ha scritto nel messaggio
news:11******** **************@ p10g2000cwp.goo glegroups.com.. .

More clumsy, but will work, is to compare with the name

if (obj.GetType(). ToString() = "System.Runtime Type") then
...
end if

will allow you to discern which of the incoming objects are types.

Never be esoteric in your code!

What about the

obj.GetType.Equ als(GetType(obj ))

?

or

obj.GetType().I sSubClassOf(Get Type(obj)))

--

Free .Net Reporting Tool - http://www.neodatatype.net

[AlanT]

-- In general it is probably better not too open an answer with a
criticism, especially when said criticism is dubious.

GetType() works on Types not objects - GetType(obj) doesn't compile
Unless I totally misunderstood the question, the issue is that objects
will be passed into the function

sub fx(obj as Object)
some of these will be actual objects - ints, strings, user defined
classes.
some of these will be Types

e.g.
fx(GetType(Stri ng))

dim i as integer
fx(i.GetType()) ' FYI, you this is how you find the type or an
object
The OP wanted to ascertain which of the incoming value were Types, not
the type of the incoming parameter.

My answer was (as I said) a touch clumsy, but did the job.

If there is another way to obtain the same result (one that actually
compiles), I would be interested in learning it.
Alan.

[Phill W.]

"Fredrik Strandberg" <be***********@ hotmail.com> wrote in message
news:11******** *************@u 72g2000cwu.goog legroups.com...

Hi!

I receive an object as a System.Object argument to a method. I need to
check if the object is a Type object or not (that is, not a specific
type, but if the object is a type object in general).

You'd be better off looking into Overloading and writing methods for
/each/ object Type that you want to process but, if you /really/ want
to do it the Hard Way, try this:

Dim thing as New SomeReferenceTy pe

If thing.GetType() .IsSubclassOf( GetType( System.Object ) ) Then
' Reference Type
Else
' Value Type
End If

Can't think why you'd want to though ... ;-)

HTH,
Phill W.

[Mattias Sjögren]

>but System.RuntimeT ype is private and not accessible - that's what the

error message says ?

More clumsy, but will work, is to compare with the name

if (obj.GetType(). ToString() = "System.Runtime Type") then

What's wrong with

If TypeOf obj Is System.Type Then
Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Larry Lard]

Fredrik Strandberg wrote:

Hi!

I receive an object as a System.Object argument to a method. I need to
check if the object is a Type object or not (that is, not a specific
type, but if the object is a type object in general). How can I do
this? Is there a way of checking if my object inherits from the
System.Type class?

The replies to this thread have astonished me.

Does this meet your requirements?

Public Sub whatisit(ByVal o As Object)
If TypeOf o Is Type Then
MsgBox("it's a type")
Else
MsgBox("it's not a type")
End If
End Sub

--
Larry Lard
Replies to group please