Why do I need to instantiate object?

Guest User

14y2kC#

Hi

I have the following code:-

IOrderedDictionary rowValues = new IOrderedDictionary();

rowValues = GetValues(GridView1.Rows[i]);

CheckBox cbRemove = new CheckBox();

cbRemove = (CheckBox)GridView1.Rows[i].FindControl("Remove");

My question is why do I need to create a instance\object of the IOrderedDictionary and CheckBox classes?

I changed the code to

IOrderedDictionary rowValues;

rowValues = GetValues(GridView1.Rows[i]);

CheckBox cbRemove;

cbRemove = (CheckBox)GridView1.Rows[i].FindControl("Remove");

And found that it still works at both compile and runtime?

Regards
Steven

4 Replies

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Vulpes14y ago
Accepted answer
You don't need to instantiate the IOrderedDictionary and CheckBox classes - and in fact you can't instantiate IOrderedDictionary anyway because it's an interface, not a class.

The changes you've made are fine. The RHS of the assignment statements produces an object which implements IOrderedDictionary and a CheckBox object. The variables, rowValues and cbRemove, then have respective references to these objects which is what you want.
Guest User14y ago
Brilliant I understand, thanks Vulpes!
Vulpes14y ago
RHS means 'right hand side'.

In general, you only need to instantiate an object if you're not otherwise getting one by invoking a method or property.

For example this is OK:

MyClass mc = GetMyClassObject();

but this is pointless:

MyClass mc = new MyClass(); // superfluous object created here
mc = GetMyClassObject();

All this does is create a superfluous object and assign it to the variable, mc. When mc is then assigned a different object, there are no longer any references to the previous object and it then becomes eligible for garbage collection without ever being used!
Guest User14y ago
Thanks Vulpes

What is RHS please?

In future would I only need to instantiate if I need access to the Members of the class ie Properties, Methods etc?

Regards
Steven