Generic interfaces in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Generic interfaces

Define generic interface IMyInterface<T>

↓

Create class MyClass implementing IMyInterface<int>

↓

Implement interface methods using T

↓

Create instance of MyClass

↓

Call interface methods with int type

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Use generic interface with different types

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END

This flow shows how to define a generic interface, implement it in a class with a specific type, and use it by calling its methods.

Execution Sample

C Sharp (C#)

interface IMyInterface<T>
{
    T GetValue();
}

class MyClass : IMyInterface<int>
{
    public int GetValue() => 42;
}

Defines a generic interface and a class implementing it with int type, returning 42.

Execution Table

Step	Action	Evaluation	Result
1	Define interface IMyInterface<T>	Generic interface created	Interface ready with method GetValue() returning T
2	Define class MyClass implementing IMyInterface<int>	Class ready	MyClass implements GetValue() returning int
3	Create instance: MyClass obj = new MyClass()	Instance created	obj is MyClass implementing IMyInterface<int>
4	Call obj.GetValue()	Method called	Returns 42
5	Use interface with different type: IMyInterface<string>	Interface type specified	Can implement with string type
6	Exit	No more steps	Execution ends

💡 All steps executed, interface and class usage demonstrated

Variable Tracker

Variable	Start	After Step 3	After Step 4	Final
obj	null	Instance of MyClass	Same instance	Same instance
Return value	N/A	N/A	42	42

Key Moments - 2 Insights

Why do we specify <int> when implementing IMyInterface?

Because the interface is generic, we must tell it which type to use. Step 2 shows MyClass implements IMyInterface<int>, so T becomes int.

Can we use the same interface with different types?

Yes, step 5 shows we can specify IMyInterface<string> or any other type, making the interface reusable.

Visual Quiz - 3 Questions

Look at the execution table, what does obj.GetValue() return at step 4?

A 0

B 42

C null

D Error

💡 Hint

Check the 'Result' column at step 4 in the execution_table

At which step is the instance of MyClass created?

A Step 1

B Step 5

C Step 3

D Step 6

💡 Hint

Look at the 'Action' column for instance creation in the execution_table

If we change MyClass to implement IMyInterface<string>, what changes in the execution?

A GetValue() must return a string

B GetValue() still returns int

C Interface becomes non-generic

D Class cannot implement interface

💡 Hint

Refer to key_moments about specifying type when implementing generic interface

Concept Snapshot

Generic interfaces allow defining interfaces with a placeholder type T.
Classes implement these interfaces by specifying a concrete type.
This makes interfaces reusable for different data types.
Syntax: interface IMyInterface<T> { T GetValue(); }
Implement: class MyClass : IMyInterface<int> { public int GetValue() => 42; }

Full Transcript

We start by defining a generic interface IMyInterface with a type parameter T. This interface declares a method GetValue that returns T. Next, we create a class MyClass that implements IMyInterface with T specified as int. Inside MyClass, GetValue returns the integer 42. We then create an instance of MyClass and call GetValue, which returns 42. The generic interface can be used with other types, like string, by specifying the type when implementing. This shows how generic interfaces provide flexibility and reusability in code.