CSharp/C#, Choose type of the object in run-time

Choose type of the object in run-time

Author	Message
<en.. #1 / 9	Choose type of the object in run-time I have the problem in C#: I have my own classes and I want to declare another object as one of these classes during run-time of my prog. Class1 object1 = new Class1(); Class2 object2 = new Class2(); object myObject = object1 Now I cannot use the methods of the Class1 type, because myObject is type of object. I want myObject to knows methods of the Class1 type.... how to do it???? I dont wanna to switch my program and check type of object1 and create Class1 myObject1 and Class2 myObject2 depends on type of object i want assign into. Thanks -- ------------------- -------------------
Sun, 31 Oct 2004 20:52:47 GMT

Peter W #2 / 9	Choose type of the object in run-time Quote: > I have the problem in C#: > I have my own classes and I want to declare another object as one of these > classes during run-time of my prog. > Class1 object1 = new Class1(); > Class2 object2 = new Class2(); > object myObject = object1 > Now I cannot use the methods of the Class1 type, because myObject is type of > object. I want myObject to knows methods of the Class1 type.... how to do > it???? Why do you cast it then? -- Peter Y. Wu "I know nothing except the fact of my ignorance." -- Socrates
Sun, 31 Oct 2004 21:24:40 GMT

Kory Postm #3 / 9	Choose type of the object in run-time What you need to do is something called casting, or type casting. If you have: Class1 c = new Class1(); object o = c; and say that 'c' has a method called 'Func()', then if you want to use 'o' and call 'Func()' it would look like this: (Class1)o.Func(); Notice the cast in front of 'o', you could also type: ((Class1)o).Func() Hope that helps, Kory Quote: > I have the problem in C#: > I have my own classes and I want to declare another object as one of these > classes during run-time of my prog. > Class1 object1 = new Class1(); > Class2 object2 = new Class2(); > object myObject = object1 > Now I cannot use the methods of the Class1 type, because myObject is type of > object. I want myObject to knows methods of the Class1 type.... how to do > it???? I dont wanna to switch my program and check type of object1 and > create Class1 myObject1 and Class2 myObject2 depends on type of object i > want assign into. > Thanks > -- > ------------------- > -------------------
Sun, 31 Oct 2004 21:24:23 GMT

<en.. #4 / 9	Choose type of the object in run-time Because I have the objects type of Class1 and Class2 saved in TreeNode.Tag object and when I take the saved object from the Tag i need to save it to one variable. I need to work with one variable. I have a lot of code that is similar to both classes (but the classes is not similar). I would retype once declared object...for example: object myObject switch(some) { case 1: Class1 myObject = SelectedTreeNode.Tag; break; case 2: Class2 myObject = SelectedTreeNode.Tag; break; Quote: } It is not possible, I know (multiple definition of one variable) Is it possible by any other way????.... :-((( -- ------------------- ------------------- Quote: > > I have the problem in C#: > > I have my own classes and I want to declare another object as one of these > > classes during run-time of my prog. > > Class1 object1 = new Class1(); > > Class2 object2 = new Class2(); > > object myObject = object1 > > Now I cannot use the methods of the Class1 type, because myObject is type of > > object. I want myObject to knows methods of the Class1 type.... how to do > > it???? > Why do you cast it then? > -- > Peter Y. Wu > "I know nothing except the fact of my ignorance." -- Socrates
Sun, 31 Oct 2004 21:35:23 GMT

<en.. #5 / 9	Choose type of the object in run-time Thanks but!!! It still says that 'object' does not contain a definition for 'Func()' (i dont wanna use function, but property. it is the same problem I think) -- ------------------- ------------------- Quote: > What you need to do is something called casting, or type casting. > If you have: > Class1 c = new Class1(); > object o = c; > and say that 'c' has a method called 'Func()', then if you want to use 'o' > and call 'Func()' it would look like this: > (Class1)o.Func(); > Notice the cast in front of 'o', you could also type: > ((Class1)o).Func() > Hope that helps, > Kory > > I have the problem in C#: > > I have my own classes and I want to declare another object as one of these > > classes during run-time of my prog. > > Class1 object1 = new Class1(); > > Class2 object2 = new Class2(); > > object myObject = object1 > > Now I cannot use the methods of the Class1 type, because myObject is type > of > > object. I want myObject to knows methods of the Class1 type.... how to do > > it???? I dont wanna to switch my program and check type of object1 and > > create Class1 myObject1 and Class2 myObject2 depends on type of object i > > want assign into. > > Thanks > > -- > > ------------------- > > -------------------
Sun, 31 Oct 2004 21:44:53 GMT

Kory Postm #6 / 9	Choose type of the object in run-time Another thing you can try (since you say casting doesn't work,. but it always should) try what is called inheritance. Make an abstract class, Abstract1 for instance and then put all of the common functionality in here, then derive Class1 and Class2 both from here and then make the differences in those classes. You can also declare abstract methods as well if the methods differ. Then when you are passing it out or whatever type cast it to Abstract1 and as long as the methods are the same name and parameter type then it should work. There should be a lot of info online about OOP and abstract classes... Kory Quote: > Because I have the objects type of Class1 and Class2 saved in TreeNode.Tag > object and when I take the saved object from the Tag i need to save it to > one variable. I need to work with one variable. I have a lot of code that is > similar to both classes (but the classes is not similar). > I would retype once declared object...for example: > object myObject > switch(some) > { > case 1: > Class1 myObject = SelectedTreeNode.Tag; > break; > case 2: > Class2 myObject = SelectedTreeNode.Tag; > break; > } > It is not possible, I know (multiple definition of one variable) > Is it possible by any other way????.... :-((( > -- > ------------------- > ------------------- > > > I have the problem in C#: > > > I have my own classes and I want to declare another object as one of > these > > > classes during run-time of my prog. > > > Class1 object1 = new Class1(); > > > Class2 object2 = new Class2(); > > > object myObject = object1 > > > Now I cannot use the methods of the Class1 type, because myObject is > type of > > > object. I want myObject to knows methods of the Class1 type.... how to > do > > > it???? > > Why do you cast it then? > > -- > > Peter Y. Wu > > "I know nothing except the fact of my ignorance." -- Socrates
Mon, 01 Nov 2004 01:53:39 GMT

Kory Postm #7 / 9	Choose type of the object in run-time If you didn't get the other message it should be in this thread. Anyhow, are you trying to do this?? You have Class1 and Class2, then you want to get Func() that is common to both of them, right? The Tag saves it as an object, and you need to typecast it back to Class1 or Class2 depending on what it is right? If that is the case you would have to know what it is and use like an if statement: (I'm not totally sure on my syntax of C# though, still learning) if (o instanceof Class1) { ((Class1)o).Func(); Quote: } else if (o instanceof Class2) { ((Class2)o.)Func(); Quote: } //(I think 'instanceof' in Java is similar to 'is' in C#) But if you read my other message and then you make an abstract class and then derive Class 1 and 2 from the abstract class then you only need one call as long as Func() is defined in the abstract class: ((Abstract)o).Func(); Then no matter what it is Class1 or Class2 they are both of type Abstract and will call the method or property or whatever... Hope that helps, Kory Quote: > Thanks but!!! > It still says that 'object' does not contain a definition for 'Func()' > (i dont wanna use function, but property. it is the same problem I think) > -- > ------------------- > ------------------- > > What you need to do is something called casting, or type casting. > > If you have: > > Class1 c = new Class1(); > > object o = c; > > and say that 'c' has a method called 'Func()', then if you want to use 'o' > > and call 'Func()' it would look like this: > > (Class1)o.Func(); > > Notice the cast in front of 'o', you could also type: > > ((Class1)o).Func() > > Hope that helps, > > Kory - Hide quoted text - - Show quoted text - Quote: > > > I have the problem in C#: > > > I have my own classes and I want to declare another object as one of > these > > > classes during run-time of my prog. > > > Class1 object1 = new Class1(); > > > Class2 object2 = new Class2(); > > > object myObject = object1 > > > Now I cannot use the methods of the Class1 type, because myObject is > type > > of > > > object. I want myObject to knows methods of the Class1 type.... how to > do > > > it???? I dont wanna to switch my program and check type of object1 and > > > create Class1 myObject1 and Class2 myObject2 depends on type of object i > > > want assign into. > > > Thanks > > > -- > > > ------------------- > > > -------------------
Mon, 01 Nov 2004 02:02:52 GMT

Jay B. Harlow [MVP - Outlook #8 / 9	Choose type of the object in run-time Endys, In addition to the other suggestions. Consider a couple of variations of what Kory Postma stated. Create an Interface that both Class1 & Class2 implement. Then instead of using a variable of type 'object' you would use a variable the type of this new interface. This interface would expose common methods used by the various TreeView events you want to handle... Further, rather than putting your classes into the Tag property of a normal TreeNode. Create a new class that inherits from TreeNode and has a property of this Interface. Plus possible exposes the methods of the interface itself. The TreeView events could call into the derived TreeNode class, the derived TreeNode class would invoke the methods of the class being referenced by the property... This leads us to another method that Kory hinted at. If possible derive Class1 & Class2 from TreeNode... or a common class derived from TreeNode... Personally I tend to prefer to a custom TreeNode that holds Class1 or Class2, separation of Business logic from User Interface logic you know... Hope this helps Jay Quote: > I have the problem in C#: > I have my own classes and I want to declare another object as one of these > classes during run-time of my prog. > Class1 object1 = new Class1(); > Class2 object2 = new Class2(); > object myObject = object1 > Now I cannot use the methods of the Class1 type, because myObject is type of > object. I want myObject to knows methods of the Class1 type.... how to do > it???? I dont wanna to switch my program and check type of object1 and > create Class1 myObject1 and Class2 myObject2 depends on type of object i > want assign into. > Thanks > -- > ------------------- > -------------------
Mon, 01 Nov 2004 10:40:31 GMT

<en.. #9 / 9	Choose type of the object in run-time OK, maybe better describtion would be this: I have a collection of different objects. I need pick up an object from this collection and assign it to another object. Do I have to check type of the object Im reading from collection and then switch between all possible object types to assign it to right object type or can I do something like: (collection.item[i].GetType()) myObject = collection.item[i]; I mean some calling type declaration by name .... for example... in Visual Basic is function CallByName(string functionName).... it is similar... I need to use type declaration by name of the type. Thanks -- ------------------- ------------------- Quote: > I have the problem in C#: > I have my own classes and I want to declare another object as one of these > classes during run-time of my prog. > Class1 object1 = new Class1(); > Class2 object2 = new Class2(); > object myObject = object1 > Now I cannot use the methods of the Class1 type, because myObject is type of > object. I want myObject to knows methods of the Class1 type.... how to do > it???? I dont wanna to switch my program and check type of object1 and > create Class1 myObject1 and Class2 myObject2 depends on type of object i > want assign into. > Thanks > -- > ------------------- > -------------------
Mon, 01 Nov 2004 21:24:35 GMT

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