Base keyword behavior in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Base keyword behavior

Derived class method called

↓

Use 'base' keyword

↓

Call base class method

↓

Execute base class method code

↓

Return to derived method

↓

Finish derived method

When a derived class method uses 'base', it calls the base class method, runs its code, then returns to finish the derived method.

Execution Sample

C Sharp (C#)

class Base {
  public virtual void Show() {
    Console.WriteLine("Base Show");
  }
}
class Derived : Base {
  public override void Show() {
    base.Show();
    Console.WriteLine("Derived Show");
  }
}
Derived d = new Derived();
d.Show();

This code calls the derived class Show method, which calls the base class Show method first, then prints its own message.

Execution Table

Step	Method Called	Action	Output
1	Derived.Show()	Starts Derived.Show method
2	Derived.Show()	Calls base.Show() using 'base' keyword
3	Base.Show()	Executes Base.Show method	Base Show
4	Derived.Show()	Returns from base.Show(), continues Derived.Show
5	Derived.Show()	Prints Derived Show message	Derived Show
6	Derived.Show()	Method ends

💡 Derived.Show() finishes after calling base.Show() and printing its own message.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	Final
Method Call Stack	Empty	Derived.Show()	base.Show() called	Inside Base.Show()	Returned to Derived.Show()	Printed Derived Show	Empty

Key Moments - 2 Insights

Why does the base class method run before the derived class prints its message?

Because the derived method explicitly calls base.Show() at step 2, so the base method runs first (steps 3-4) before continuing.

What happens if we remove 'base.Show()' call in the derived method?

The base class method won't run, so only 'Derived Show' prints. The execution_table would skip steps 2 and 3.

Visual Quiz - 3 Questions

Look at the execution table, what is printed at step 3?

A Derived Show

B Base Show

C Nothing

D Error

💡 Hint

Check the Output column at step 3 in the execution_table.

At which step does the derived method resume after calling the base method?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look for the step where the action says 'Returned to Derived.Show()' in the execution_table.

If 'base.Show()' is removed, which steps disappear from the execution_table?

A Steps 2 and 3

B Steps 1 and 6

C Steps 4 and 5

D No steps disappear

💡 Hint

Check which steps involve calling and executing base.Show() in the execution_table.

Concept Snapshot

Base keyword calls base class method from derived class.
Use 'base.MethodName()' inside derived method.
Base method runs first, then derived continues.
Without 'base', base method is skipped.
Useful to extend or reuse base behavior.

Full Transcript

This visual trace shows how the 'base' keyword works in C#. When a derived class method calls 'base.Method()', it runs the base class method code first, then returns to finish the derived method. The execution table tracks each step: starting the derived method, calling the base method, executing base code, returning, and finishing derived code. Variables like the call stack show method calls and returns. Key moments clarify why base runs first and what happens if 'base' call is removed. The quiz tests understanding of output and flow. The snapshot summarizes the base keyword usage simply.