Hello,
I have created a class that inherits MembershipUser:
public class UserHelper : MembershipUser {
....
Then I am creating a user as follows:
UserHelper user = (UserHelper)Membership.CreateUser("me", "pass",
"me@domain.com", null, null, true, null, out status);
Membership.CreateUser returns a MembershipUser
But I get an error:
Unable to cast object of type 'System.Web.Security.MembershipUser' to
type 'MyApp.Security.Membership.UserHelper'.
If I don't cast it, which means, using:
UserHelper user = Membership.CreateUser("me", "pass", "me@domain.com",
null, null, true, null, out status);
It does not compile and I get the error:
Cannot implicitly convert type 'System.Web.Security.MembershipUser' to
'MyApp.Security.Membership.UserHelper'. An explicit conversion exists
(are you missing a cast?)
What am I doing wrong?
Thanks,
Miguel 2 3431
On Sat, 01 Nov 2008 10:28:10 -0700, shapper <md*****@gmail.comwrote:
Hello,
I have created a class that inherits MembershipUser:
public class UserHelper : MembershipUser {
...
Then I am creating a user as follows:
UserHelper user = (UserHelper)Membership.CreateUser("me", "pass",
"me@domain.com", null, null, true, null, out status);
Membership.CreateUser returns a MembershipUser
If the object is not a UserHelper instance, you simply cannot cast it to
UserHelper. It's just not possible.
Note that in the second case, where you don't cast it and the compiler
says "an explicit conversion exists", it only means that in the
syntactical sense. It has no way to verify whether the conversion will
actually _succeed_...just that you can attempt it explicitly with a cast.
Pete
shapper <md*****@gmail.comwrote:
> I have created a class that inherits MembershipUser: public class UserHelper : MembershipUser { ...
Then I am creating a user as follows: UserHelper user = (UserHelper)Membership.CreateUser("me", "pass", "me@domain.com", null, null, true, null, out status);
Membership.CreateUser returns a MembershipUser
But I get an error: Unable to cast object of type 'System.Web.Security.MembershipUser' to type 'MyApp.Security.Membership.UserHelper'.
If I don't cast it, which means, using: UserHelper user = Membership.CreateUser("me", "pass", "me@domain.com", null, null, true, null, out status);
It does not compile and I get the error: Cannot implicitly convert type 'System.Web.Security.MembershipUser' to 'MyApp.Security.Membership.UserHelper'. An explicit conversion exists (are you missing a cast?)
What am I doing wrong?
You're casting in the wrong direction. If you have a UserHelper, you can
cast it to a MembershipUser, but you cannot safely start with a base object
and cast it to a derived class. What would happen to any additional
members you might have added? They wouldn't be present in the
MembershipUser instance.
In this case, you will have to use composition instead of inheritance. Add
a MembershipUser instance to UserHelper ad a member, call CreateUser, and
pass the MembershipUser object you get to the constructor for UserHelper.
--
Tim Roberts, ti**@probo.com
Providenza & Boekelheide, Inc. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Jacob Jensen |
last post by:
This question has probably been asked a million time, but here it comes
again. I want to learn the difference between the three type cast operators:
static_cast, reinterpret_cast, dynamic_cast. A...
|
by: Brian Blais |
last post by:
Hello,
I saw on a couple of recent posts people saying that casting the return
value of malloc is bad, like:
d=(double *) malloc(50*sizeof(double));
why is this bad? I had always thought...
|
by: ytrama |
last post by:
Hi,
I have read in one of old posting that don't cast of pointer which
is returned by the malloc. I would like to know the reason.
Thanks in advance,
YTR
|
by: yufufi |
last post by:
lets say we have a 'shape' class which doesn't implement IComparable
interface..
compiler doesn't give you error for the lines below..
shape b= new shape();
IComparable h;
h=(IComparable)b;...
|
by: Jim Bancroft |
last post by:
Hi everyone,
A basic one here, I think. I haven't found the pattern yet, but
sometimes when I cast a variable to another type using the "C" style cast
operator the compiler refuses to play...
| |
by: Enrique Bustamante |
last post by:
Casting arrays that works on watch and command window but not in code.
My application is casting arrays in a way it should work. To test if I
was doing something invalid, I wrote a test code that...
|
by: S. Lorétan |
last post by:
Hi guys,
Sorry for this stupid question, but I don't know why it isn't working.
Here is my (example) code:
namespace Test {
class A {
public string Label1;
}
|
by: sophia.agnes |
last post by:
Hi ,
I was going through peter van der linden's book Expert C programming,
in this book there is a section named "How and why to cast"
the author then says as follows
(float) 3 - it's a...
|
by: Taras_96 |
last post by:
Hi everyone,
I was experimenting with static_cast and reinterpret cast
#include <iostream>
struct A1 { int a; };
struct A2 { double d; };
struct B : public A1, A2
|
by: Tinkertim |
last post by:
Hi,
I have often wondered if casting the return value of malloc() (or
friends) actually helps anything, recent threads here suggest that it
does not .. so I hope to find out.
For instance :
...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...
| |
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers,...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows...
|
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new...
| |
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The...
| |