Creating an object depending on a value of a parameter

[Chamith]

Hi all,
I have a method which takes a string parameter. It takes a type name as a
string.
Inside the method, i want to create an instance of the type which is
mentioned in the string parameter.

Please help me providing with some example code.

Thanks,

Chamith

[Mohamoss]

Hi Chamith
If the set of the types you are reciving as input to this method is
finite , you can do it inside a switch statement
switch type{
case "int " : //create you int object
case "string"://create you string object
default : // not a recognized type , return an erro message

}
Mohamed Mahfouz
MEA Developer Support Center
ITworx on behalf of Microsoft EMEA GTSC

[Jon Skeet [C# MVP]]

Chamith <ch********@gmail.com> wrote:

I have a method which takes a string parameter. It takes a type name as a
string.
Inside the method, i want to create an instance of the type which is
mentioned in the string parameter.

Please help me providing with some example code.

Look at the docs for Activator.CreateInstance. Sample code:

using System;

class Test
{
static void Main()
{
string typeName = "Foo";

Type t = Type.GetType (typeName);
object o = Activator.CreateInstance(t);
}
}

class Foo
{
public Foo()
{
Console.WriteLine ("Constructing instance of Foo");
}
}

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Richard Blewett [DevelopMentor]]

If the type to be created is in the same assembly as the creating function then

object CreateIt(string typename)
{
Type t = Type.GetType(typename);
object o = Activator.CreateInstance(t);
return o;
}

if the type isn't in the same assembly (or in mscorlib) then you haven't got enough information to create the type

Regards

Richard Belwett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi all,
I have a method which takes a string parameter. It takes a type name as a
string.
Inside the method, i want to create an instance of the type which is
mentioned in the string parameter.

Please help me providing with some example code.

Thanks,

Chamith

[Chamith]

Hi,

Thanks a lot for all your replies. Those are really usefull.
One more thing i got to ask.
Once the object is created, it's type is System.Object.
Since i need to get all the functionaly of the specific type i'm creating, i
need to cast it to that particular type explicitly.
but.. coz i dont know what the 'exact type' is until the runtime, is there a
way to do it?

want to do it like this.

Type t = Type.GetType(typename);
MySpecificType o = (MySpecificType)Activator.CreateInstance(t);

Thanks,

Chamith

"Chamith" <ch********@gmail.com> wrote in message
news:#o**************@TK2MSFTNGP10.phx.gbl...

Hi all,
I have a method which takes a string parameter. It takes a type name as a
string.
Inside the method, i want to create an instance of the type which is
mentioned in the string parameter.

Please help me providing with some example code.

Thanks,

Chamith

[Richard Blewett [DevelopMentor]]

Use a common base class or interface and return that from the method

MyBase CreateIt(string typename)
{
object o = Activator.CreateInstance(Type.GetType(typename));
return (MyBase)o;
}

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

Thanks a lot for all your replies. Those are really usefull.
One more thing i got to ask.
Once the object is created, it's type is System.Object.
Since i need to get all the functionaly of the specific type i'm creating, i
need to cast it to that particular type explicitly.
but.. coz i dont know what the 'exact type' is until the runtime, is there a
way to do it?

want to do it like this.

Type t = Type.GetType(typename);
MySpecificType o = (MySpecificType)Activator.CreateInstance(t);

Thanks,

Chamith

[Dino Chiesa [Microsoft]]

Interesting article related to designing plug-in -based apps in .NET
http://www.divil.co.uk/net/articles/plugins/plugins.asp
"Richard Blewett [DevelopMentor]" <ri******@NOSPAMdevelop.com> wrote in
message news:Oo**************@TK2MSFTNGP15.phx.gbl...

Use a common base class or interface and return that from the method

MyBase CreateIt(string typename)
{
object o = Activator.CreateInstance(Type.GetType(typename));
return (MyBase)o;
}

Regards

Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog
http://www.dotnetconsult.co.uk

Hi,

Thanks a lot for all your replies. Those are really usefull.
One more thing i got to ask.
Once the object is created, it's type is System.Object.
Since i need to get all the functionaly of the specific type i'm creating,
i
need to cast it to that particular type explicitly.
but.. coz i dont know what the 'exact type' is until the runtime, is there
a
way to do it?

want to do it like this.

Type t = Type.GetType(typename);
MySpecificType o = (MySpecificType)Activator.CreateInstance(t);

Thanks,

Chamith

[Debasish Bose]

Hi,
As Dino said, use any "good-old" polymorphic technique like Interface
or BaseClass.

"Chamith" <ch********@gmail.com> wrote in message
news:uL**************@TK2MSFTNGP10.phx.gbl...

Hi,

Thanks a lot for all your replies. Those are really usefull.
One more thing i got to ask.
Once the object is created, it's type is System.Object.
Since i need to get all the functionaly of the specific type i'm creating, i need to cast it to that particular type explicitly.
but.. coz i dont know what the 'exact type' is until the runtime, is there a way to do it?

want to do it like this.

Type t = Type.GetType(typename);
MySpecificType o = (MySpecificType)Activator.CreateInstance(t);

Thanks,

Chamith

"Chamith" <ch********@gmail.com> wrote in message
news:#o**************@TK2MSFTNGP10.phx.gbl...

Hi all,
I have a method which takes a string parameter. It takes a type name as a string.
Inside the method, i want to create an instance of the type which is
mentioned in the string parameter.

Please help me providing with some example code.

Thanks,

Chamith