call a method in an external class

[keith]

I created a class libery which has name space Assembly
and class Assembly and compiled it.

Then created a C# project and called a method in
the external class

e.g.

Assembly dll;
dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
object obj=dll.CreateI nstance("Assemb ly.Assembly");
obj.func();

When compiling, it said "'object' does not contain a
deifinition for 'func'

But if created a VB.NET project
e.g.

Dim dll As Assembly
dll = System.Reflecti on.Assembly.Loa dFrom
("c:\app\Assemb ly.dll")
Dim obj As Object
obj = dll.CreateInsta nce("Assembly.A ssembly")
obj.func()

I compiled and ran it without any problem.

Can you tell what is problem?

Thanks

[Nicholas Paldino [.NET/C# MVP]]

Keith,

The reason for this is that the reference is of type object. You have
to cast obj to "Assembly.Assem bly" in order to call the method, like this:

// Create the instance.
Assembly.Assemb ly obj = (Assembly.Assem bly)
dll.CreateInsta nce("Assembly.A ssembly");

You can then use obj to call the func method.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:02******** *************** *****@phx.gbl.. .

I created a class libery which has name space Assembly
and class Assembly and compiled it.

Then created a C# project and called a method in
the external class

e.g.

Assembly dll;
dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
object obj=dll.CreateI nstance("Assemb ly.Assembly");
obj.func();

When compiling, it said "'object' does not contain a
deifinition for 'func'

But if created a VB.NET project
e.g.

Dim dll As Assembly
dll = System.Reflecti on.Assembly.Loa dFrom
("c:\app\Assemb ly.dll")
Dim obj As Object
obj = dll.CreateInsta nce("Assembly.A ssembly")
obj.func()

I compiled and ran it without any problem.

Can you tell what is problem?

Thanks

[Martin Honnen]

keith wrote:

I created a class libery which has name space Assembly
and class Assembly and compiled it.

Then created a C# project and called a method in
the external class

e.g.

Assembly dll;
dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
object obj=dll.CreateI nstance("Assemb ly.Assembly");
obj.func();

When compiling, it said "'object' does not contain a
deifinition for 'func'

But if created a VB.NET project
e.g.

Dim dll As Assembly
dll = System.Reflecti on.Assembly.Loa dFrom
("c:\app\Assemb ly.dll")
Dim obj As Object
obj = dll.CreateInsta nce("Assembly.A ssembly")
obj.func()

I compiled and ran it without any problem.

Can you tell what is problem?

Are you sure func is an instance member and not a class member
--

Martin Honnen
http://JavaScript.FAQTs.com/

[keith]

Nicholas,

This will not work since the Assembly.Assemb ly is
an external class in an dll file that dosen't have
reference in my project that will use it.

Thanks
Keith

-----Original Message-----
Keith,

The reason for this is that the reference is of type object. You haveto cast obj to "Assembly.Assem bly" in order to call the method, like this:
// Create the instance.
Assembly.Assem bly obj = (Assembly.Assem bly)
dll.CreateInst ance("Assembly. Assembly");

You can then use obj to call the func method.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:02******* *************** ******@phx.gbl. ..

I created a class libery which has name space Assembly
and class Assembly and compiled it.

Then created a C# project and called a method in
the external class

e.g.

Assembly dll;
dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
object obj=dll.CreateI nstance("Assemb ly.Assembly");
obj.func();

When compiling, it said "'object' does not contain a
deifinition for 'func'

But if created a VB.NET project
e.g.

Dim dll As Assembly
dll = System.Reflecti on.Assembly.Loa dFrom
("c:\app\Assemb ly.dll")
Dim obj As Object
obj = dll.CreateInsta nce("Assembly.A ssembly")
obj.func()

I compiled and ran it without any problem.

Can you tell what is problem?

Thanks

.

[Nicholas Paldino [.NET/C# MVP]]

Keith,

In that case, you have two options. The first is to have a base class
which exposes the methods of Assembly.Assemb ly which is accessible to both
Assembly.dll and to the code loading it dynamically, and then cast to the
base type. You can also do this with an interface. The key is to have both
assemblies able to access the interface/base class definition, and the one
loading Assembly.Assemb ly dynamically doesn't have to access the class that
has the implementation directly.

The only other option is to use reflection to call the method.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:01******** *************** *****@phx.gbl.. .

Nicholas,

This will not work since the Assembly.Assemb ly is
an external class in an dll file that dosen't have
reference in my project that will use it.

Thanks
Keith

-----Original Message-----
Keith,

The reason for this is that the reference is of type

object. You have

to cast obj to "Assembly.Assem bly" in order to call the

method, like this:

// Create the instance.
Assembly.Assem bly obj = (Assembly.Assem bly)
dll.CreateInst ance("Assembly. Assembly");

You can then use obj to call the func method.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:02******* *************** ******@phx.gbl. ..

I created a class libery which has name space Assembly
and class Assembly and compiled it.

Then created a C# project and called a method in
the external class

e.g.

Assembly dll;
dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
object obj=dll.CreateI nstance("Assemb ly.Assembly");
obj.func();

When compiling, it said "'object' does not contain a
deifinition for 'func'

But if created a VB.NET project
e.g.

Dim dll As Assembly
dll = System.Reflecti on.Assembly.Loa dFrom
("c:\app\Assemb ly.dll")
Dim obj As Object
obj = dll.CreateInsta nce("Assembly.A ssembly")
obj.func()

I compiled and ran it without any problem.

Can you tell what is problem?

Thanks

.

[keith]

I'm sure.

I did use same method in an external class (a dll file).

Then I tried call the method from both C# and VB.NET
by using almost same codes. It worked for VB but not
in C#.

-----Original Message-----
keith wrote:

I created a class libery which has name space Assembly
and class Assembly and compiled it.

Then created a C# project and called a method in
the external class

e.g.

Assembly dll;
dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
object obj=dll.CreateI nstance("Assemb ly.Assembly");
obj.func();

When compiling, it said "'object' does not contain a deifinition for 'func'

But if created a VB.NET project
e.g.

Dim dll As Assembly
dll = System.Reflecti on.Assembly.Loa dFrom
("c:\app\Assemb ly.dll")
Dim obj As Object
obj = dll.CreateInsta nce("Assembly.A ssembly")
obj.func()

I compiled and ran it without any problem.

Can you tell what is problem?
Are you sure func is an instance member and not a class

member--

Martin Honnen
http://JavaScript.FAQTs.com/

.

[keith]

My purpose is to call a method in a external file
dynamically. So I don't want to use base class or
interface.

I did use reflection in both VB.NET and
C# project. used almost same codes (please compare
the codes in my first email) to load and create instance,
finally call the method.

It worked for VB.NET but not C#. It surprised me since I
should be able to do samething in either language.
Thanks

Keith

-----Original Message-----
Keith,

In that case, you have two options. The first is to have a base classwhich exposes the methods of Assembly.Assemb ly which is accessible to bothAssembly.dll and to the code loading it dynamically, and then cast to thebase type. You can also do this with an interface. The key is to have bothassemblies able to access the interface/base class definition, and the oneloading Assembly.Assemb ly dynamically doesn't have to access the class thathas the implementation directly.

The only other option is to use reflection to call the method.

--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:01******* *************** ******@phx.gbl. ..

Nicholas,

This will not work since the Assembly.Assemb ly is
an external class in an dll file that dosen't have
reference in my project that will use it.

Thanks
Keith

>-----Original Message-----
>Keith,
>
> The reason for this is that the reference is of type

object. You have

>to cast obj to "Assembly.Assem bly" in order to call

the method, like this:

>
>// Create the instance.
>Assembly.Assem bly obj = (Assembly.Assem bly)
>dll.CreateInst ance("Assembly. Assembly");
>
> You can then use obj to call the func method.
>
> Hope this helps.
>
>
>--
> - Nicholas Paldino [.NET/C# MVP]
> - ni************* *@exisconsultin g.com
>
>"keith" <ke*****@shaw.c a> wrote in message
>news:02******* *************** ******@phx.gbl. ..
>> I created a class libery which has name space

Assembly >> and class Assembly and compiled it.
>>
>> Then created a C# project and called a method in
>> the external class
>>
>> e.g.
>>
>> Assembly dll;
>> dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
>> object obj=dll.CreateI nstance("Assemb ly.Assembly");
>> obj.func();
>>
>> When compiling, it said "'object' does not contain a
>> deifinition for 'func'
>>
>> But if created a VB.NET project
>> e.g.
>>
>> Dim dll As Assembly
>> dll = System.Reflecti on.Assembly.Loa dFrom
>> ("c:\app\Assemb ly.dll")
>> Dim obj As Object
>> obj = dll.CreateInsta nce("Assembly.A ssembly")
>> obj.func()
>>
>> I compiled and ran it without any problem.
>>
>> Can you tell what is problem?
>>
>> Thanks
>
>
>.
>

.

[Nicholas Paldino [.NET/C# MVP]]

Keith,

In VB, if you make a method call on type object, it will perform all of
the reflection work for you. VB and C# can do the same things, they just go
about it differently.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:04******** *************** *****@phx.gbl.. .

My purpose is to call a method in a external file
dynamically. So I don't want to use base class or
interface.

I did use reflection in both VB.NET and
C# project. used almost same codes (please compare
the codes in my first email) to load and create instance,
finally call the method.

It worked for VB.NET but not C#. It surprised me since I
should be able to do samething in either language.
Thanks

Keith

-----Original Message-----
Keith,

In that case, you have two options. The first is to

have a base class

which exposes the methods of Assembly.Assemb ly which is

accessible to both

Assembly.dll and to the code loading it dynamically, and

then cast to the

base type. You can also do this with an interface. The

key is to have both

assemblies able to access the interface/base class

definition, and the one

loading Assembly.Assemb ly dynamically doesn't have to

access the class that

has the implementation directly.

The only other option is to use reflection to call

the method.

--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:01******* *************** ******@phx.gbl. ..

Nicholas,

This will not work since the Assembly.Assemb ly is
an external class in an dll file that dosen't have
reference in my project that will use it.

Thanks
Keith
>-----Original Message-----
>Keith,
>
> The reason for this is that the reference is of type object. You have
>to cast obj to "Assembly.Assem bly" in order to call the method, like this:
>
>// Create the instance.
>Assembly.Assem bly obj = (Assembly.Assem bly)
>dll.CreateInst ance("Assembly. Assembly");
>
> You can then use obj to call the func method.
>
> Hope this helps.
>
>
>--
> - Nicholas Paldino [.NET/C# MVP]
> - ni************* *@exisconsultin g.com
>
>"keith" <ke*****@shaw.c a> wrote in message
>news:02******* *************** ******@phx.gbl. ..
>> I created a class libery which has name space Assembly >> and class Assembly and compiled it.
>>
>> Then created a C# project and called a method in
>> the external class
>>
>> e.g.
>>
>> Assembly dll;
>> dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
>> object obj=dll.CreateI nstance("Assemb ly.Assembly");
>> obj.func();
>>
>> When compiling, it said "'object' does not contain a
>> deifinition for 'func'
>>
>> But if created a VB.NET project
>> e.g.
>>
>> Dim dll As Assembly
>> dll = System.Reflecti on.Assembly.Loa dFrom
>> ("c:\app\Assemb ly.dll")
>> Dim obj As Object
>> obj = dll.CreateInsta nce("Assembly.A ssembly")
>> obj.func()
>>
>> I compiled and ran it without any problem.
>>
>> Can you tell what is problem?
>>
>> Thanks
>
>
>.
>

.

[keith]

Nicholas,

How to get samething work for C#?

Keith

-----Original Message-----
Keith,

In VB, if you make a method call on type object, it will perform all ofthe reflection work for you. VB and C# can do the same things, they just goabout it differently.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:04******* *************** ******@phx.gbl. ..

My purpose is to call a method in a external file
dynamically. So I don't want to use base class or
interface.

I did use reflection in both VB.NET and
C# project. used almost same codes (please compare
the codes in my first email) to load and create instance, finally call the method.

It worked for VB.NET but not C#. It surprised me since I should be able to do samething in either language.
Thanks

Keith

>-----Original Message-----
>Keith,
>
> In that case, you have two options. The first is to

have a base class

>which exposes the methods of Assembly.Assemb ly which

is accessible to both

>Assembly.dll and to the code loading it dynamically,

and then cast to the

>base type. You can also do this with an interface.

The key is to have both

>assemblies able to access the interface/base class

definition, and the one

>loading Assembly.Assemb ly dynamically doesn't have to

access the class that

>has the implementation directly.
>
> The only other option is to use reflection to call

the method.

>
>
>--
> - Nicholas Paldino [.NET/C# MVP]
> - ni************* *@exisconsultin g.com
>
>"keith" <ke*****@shaw.c a> wrote in message
>news:01******* *************** ******@phx.gbl. ..
>> Nicholas,
>>
>> This will not work since the Assembly.Assemb ly is
>> an external class in an dll file that dosen't have
>> reference in my project that will use it.
>>
>> Thanks
>> Keith
>>
>>
>> >-----Original Message-----
>> >Keith,
>> >
>> > The reason for this is that the reference is of

type

>> object. You have
>> >to cast obj to "Assembly.Assem bly" in order to call

the

>> method, like this:
>> >
>> >// Create the instance.
>> >Assembly.Assem bly obj = (Assembly.Assem bly)
>> >dll.CreateInst ance("Assembly. Assembly");
>> >
>> > You can then use obj to call the func method.
>> >
>> > Hope this helps.
>> >
>> >
>> >--
>> > - Nicholas Paldino [.NET/C# MVP]
>> > -

ni************* *@exisconsultin g.com >> >
>> >"keith" <ke*****@shaw.c a> wrote in message
>> >news:02******* *************** ******@phx.gbl. ..
>> >> I created a class libery which has name space

Assembly

>> >> and class Assembly and compiled it.
>> >>
>> >> Then created a C# project and called a method in
>> >> the external class
>> >>
>> >> e.g.
>> >>
>> >> Assembly dll;
>> >> dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
>> >> object obj=dll.CreateI nstance ("Assembly.Asse mbly"); >> >> obj.func();
>> >>
>> >> When compiling, it said "'object' does not contain a >> >> deifinition for 'func'
>> >>
>> >> But if created a VB.NET project
>> >> e.g.
>> >>
>> >> Dim dll As Assembly
>> >> dll = System.Reflecti on.Assembly.Loa dFrom
>> >> ("c:\app\Assemb ly.dll")
>> >> Dim obj As Object
>> >> obj = dll.CreateInsta nce("Assembly.A ssembly")
>> >> obj.func()
>> >>
>> >> I compiled and ran it without any problem.
>> >>
>> >> Can you tell what is problem?
>> >>
>> >> Thanks
>> >
>> >
>> >.
>> >
>
>
>.
>

.

[Nicholas Paldino [.NET/C# MVP]]

Keith,

You must use reflection, getting the MethodInfo instance for the method,
and then Invoking it.

You really should consider using an interface, it's just better design,
and you get the type safety.

I should ammend my statement from before, VB and C# can't do everything
the other can do, but most things.

--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:8a******** *************** *****@phx.gbl.. .

Nicholas,

How to get samething work for C#?

Keith

-----Original Message-----
Keith,

In VB, if you make a method call on type object, it

will perform all of

the reflection work for you. VB and C# can do the same

things, they just go

about it differently.
--
- Nicholas Paldino [.NET/C# MVP]
- ni************* *@exisconsultin g.com

"keith" <ke*****@shaw.c a> wrote in message
news:04******* *************** ******@phx.gbl. ..

My purpose is to call a method in a external file
dynamically. So I don't want to use base class or
interface.

I did use reflection in both VB.NET and
C# project. used almost same codes (please compare
the codes in my first email) to load and create instance, finally call the method.

It worked for VB.NET but not C#. It surprised me since I should be able to do samething in either language.
Thanks

Keith


>-----Original Message-----
>Keith,
>
> In that case, you have two options. The first is to have a base class
>which exposes the methods of Assembly.Assemb ly which is accessible to both
>Assembly.dll and to the code loading it dynamically, and then cast to the
>base type. You can also do this with an interface. The key is to have both
>assemblies able to access the interface/base class
definition, and the one
>loading Assembly.Assemb ly dynamically doesn't have to
access the class that
>has the implementation directly.
>
> The only other option is to use reflection to call
the method.
>
>
>--
> - Nicholas Paldino [.NET/C# MVP]
> - ni************* *@exisconsultin g.com
>
>"keith" <ke*****@shaw.c a> wrote in message
>news:01******* *************** ******@phx.gbl. ..
>> Nicholas,
>>
>> This will not work since the Assembly.Assemb ly is
>> an external class in an dll file that dosen't have
>> reference in my project that will use it.
>>
>> Thanks
>> Keith
>>
>>
>> >-----Original Message-----
>> >Keith,
>> >
>> > The reason for this is that the reference is of
type
>> object. You have
>> >to cast obj to "Assembly.Assem bly" in order to call
the
>> method, like this:
>> >
>> >// Create the instance.
>> >Assembly.Assem bly obj = (Assembly.Assem bly)
>> >dll.CreateInst ance("Assembly. Assembly");
>> >
>> > You can then use obj to call the func method.
>> >
>> > Hope this helps.
>> >
>> >
>> >--
>> > - Nicholas Paldino [.NET/C# MVP]
>> > - ni************* *@exisconsultin g.com >> >
>> >"keith" <ke*****@shaw.c a> wrote in message
>> >news:02******* *************** ******@phx.gbl. ..
>> >> I created a class libery which has name space
Assembly
>> >> and class Assembly and compiled it.
>> >>
>> >> Then created a C# project and called a method in
>> >> the external class
>> >>
>> >> e.g.
>> >>
>> >> Assembly dll;
>> >> dll=Assembly.Lo adFrom(@"c:\app \Assembly.dll") ;
>> >> object obj=dll.CreateI nstance ("Assembly.Asse mbly"); >> >> obj.func();
>> >>
>> >> When compiling, it said "'object' does not contain a >> >> deifinition for 'func'
>> >>
>> >> But if created a VB.NET project
>> >> e.g.
>> >>
>> >> Dim dll As Assembly
>> >> dll = System.Reflecti on.Assembly.Loa dFrom
>> >> ("c:\app\Assemb ly.dll")
>> >> Dim obj As Object
>> >> obj = dll.CreateInsta nce("Assembly.A ssembly")
>> >> obj.func()
>> >>
>> >> I compiled and ran it without any problem.
>> >>
>> >> Can you tell what is problem?
>> >>
>> >> Thanks
>> >
>> >
>> >.
>> >
>
>
>.
>

.