Creating object but not using the standart way :(

[CreateObject]

Assume that I have the classes below;

class mercedes: IAuto {
....
}

class ford: IAuto{
....
}

class audi: IAuto{
....
}

Is it possible to create objects derived from these classes by just using
strings. In other words, CreateObject("m ercedes") will return mercedes
object and so CreateObject("f ord") will give me the ford one...

It is important for me that the way you are suggesting must not use the
conditional things like if or switch.
How can I do that?

Thanks.

[Bruce Wood]

Look into the Reflection namespace. Reflection allows you to create
objects and invoke their properties, methods, etc. where their types
are not known at compile time.

[Ignacio Machin \( .NET/ C# MVP \)]

HI,
Of course :)

Take a look at CreateInstance method, two classes implement it, AppDomain &
Activator , depending of what you have ( assembly where they were defined,
complete name, etc) you can use either one.
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

Assume that I have the classes below;

class mercedes: IAuto {
...
}

class ford: IAuto{
...
}

class audi: IAuto{
...
}

Is it possible to create objects derived from these classes by just using
strings. In other words, CreateObject("m ercedes") will return mercedes
object and so CreateObject("f ord") will give me the ford one...

It is important for me that the way you are suggesting must not use the
conditional things like if or switch.
How can I do that?

Thanks.

[CreateObject]

Thanx for your rapid answers :)
However, I got the following error :(

System.TypeLoad Exception: Could not load type 'NameSpaceThing .Class1' from
assembly 'App_Web_xcjnbo z6, Version=0.0.0.0 , Culture=neutral ,
PublicKeyToken= null'.
Class1 myCla1 = new Class1();
//works fine
object px = Activator.Creat eInstance(null, "NameSpaceThing .Class1");
//throws error

namespace NameSpaceThing
{
public class Class1
{
public Class1()
{

}
}
}


"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us >, haber
iletisinde þunlarý yazdý:ut******* *******@TK2MSFT NGP02.phx.gbl.. .

HI,
Of course :)

Take a look at CreateInstance method, two classes implement it, AppDomain
& Activator , depending of what you have ( assembly where they were
defined, complete name, etc) you can use either one.
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

Assume that I have the classes below;

class mercedes: IAuto {
...
}

class ford: IAuto{
...
}

class audi: IAuto{
...
}

Is it possible to create objects derived from these classes by just using
strings. In other words, CreateObject("m ercedes") will return mercedes
object and so CreateObject("f ord") will give me the ford one...

It is important for me that the way you are suggesting must not use the
conditional things like if or switch.
How can I do that?

Thanks.

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

Is the code in the same assembly where you define your class?
from the error message it seems not.

what if you call it like:
object px = Activator.Creat eInstance( "NameSpaceThing " , "Class1");

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:eB******** ******@TK2MSFTN GP02.phx.gbl...

Thanx for your rapid answers :)
However, I got the following error :(

System.TypeLoad Exception: Could not load type 'NameSpaceThing .Class1' from
assembly 'App_Web_xcjnbo z6, Version=0.0.0.0 , Culture=neutral ,
PublicKeyToken= null'.
Class1 myCla1 = new Class1(); //works fine
object px = Activator.Creat eInstance(null, "NameSpaceThing .Class1");
//throws error

namespace NameSpaceThing
{
public class Class1
{
public Class1()
{

}
}
}


"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us >,
haber iletisinde þunlarý yazdý:ut******* *******@TK2MSFT NGP02.phx.gbl.. .

HI,
Of course :)

Take a look at CreateInstance method, two classes implement it, AppDomain
& Activator , depending of what you have ( assembly where they were
defined, complete name, etc) you can use either one.
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

Assume that I have the classes below;

class mercedes: IAuto {
...
}

class ford: IAuto{
...
}

class audi: IAuto{
...
}

Is it possible to create objects derived from these classes by just
using strings. In other words, CreateObject("m ercedes") will return
mercedes object and so CreateObject("f ord") will give me the ford one...

It is important for me that the way you are suggesting must not use the
conditional things like if or switch.
How can I do that?

Thanks.

[CreateObject]

My class is not in the same assembly where I call Activator.Creat eInstance()
method.

these are differen classed stored in different files under different paths
Default.cs
namespace NameSpaceThing
{
public partial class _Default : System.Web.UI.P age
{
protected void Page_Load(objec t sender, EventArgs e)
{
Class1 objCls = new Class1();
object px = Activator.Creat eInstance(null,
"NameSpaceThing .Class1");
}
}
}

and my class Class1.cs

namespace NameSpaceThing
{
public class Class1
{
public Class1()
{
...
}
}
}

I also tried what you've suggested but nothing has changed
again :(
"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us >, haber
iletisinde þunlarý yazdý:OO******* *******@TK2MSFT NGP02.phx.gbl.. .

Hi,

Is the code in the same assembly where you define your class?
from the error message it seems not.

what if you call it like:
object px = Activator.Creat eInstance( "NameSpaceThing " , "Class1");

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:eB******** ******@TK2MSFTN GP02.phx.gbl...

Thanx for your rapid answers :)
However, I got the following error :(

System.TypeLoad Exception: Could not load type 'NameSpaceThing .Class1'
from assembly 'App_Web_xcjnbo z6, Version=0.0.0.0 , Culture=neutral ,
PublicKeyToken= null'.
Class1 myCla1 = new Class1(); //works fine
object px = Activator.Creat eInstance(null, "NameSpaceThing .Class1");
//throws error

namespace NameSpaceThing
{
public class Class1
{
public Class1()
{

}
}
}


"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us >,
haber iletisinde þunlarý yazdý:ut******* *******@TK2MSFT NGP02.phx.gbl.. .

HI,
Of course :)

Take a look at CreateInstance method, two classes implement it,
AppDomain & Activator , depending of what you have ( assembly where they
were defined, complete name, etc) you can use either one.
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..
Assume that I have the classes below;

class mercedes: IAuto {
...
}

class ford: IAuto{
...
}

class audi: IAuto{
...
}

Is it possible to create objects derived from these classes by just
using strings. In other words, CreateObject("m ercedes") will return
mercedes object and so CreateObject("f ord") will give me the ford
one...

It is important for me that the way you are suggesting must not use the
conditional things like if or switch.
How can I do that?

Thanks.

[Nick Hounsome]

"CreateObje ct" <ha*********@gm ail.com> wrote in message
news:%2******** ********@TK2MSF TNGP03.phx.gbl. ..

Assume that I have the classes below;

class mercedes: IAuto {
...
}

class ford: IAuto{
...
}

class audi: IAuto{
...
}

Is it possible to create objects derived from these classes by just using
strings. In other words, CreateObject("m ercedes") will return mercedes
object and so CreateObject("f ord") will give me the ford one...

It is important for me that the way you are suggesting must not use the
conditional things like if or switch.
How can I do that?

Thanks.

A lot of people are going to tell you how to do this with reflection but,
except when using plugins, reflection is not necessary and should be avoided
wherever possible for security, maintainability and correctness reasons.

You can avoid switch statements by using a dictionary to look up a delegate
to construct the appropriate object.

Of course the dictionary has to be built explicitly but at least you know
that you are not going to get a security exception and you know and can
control exactly what can and cannot be instantiated.