2nd/10_Wiki/Topics/Domain_Programming/Topic_CSharp/CSharp_Exceptions.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
csharp-exceptions	C# Exceptions - Try..Catch	Programming_Language	draft	conceptual		try catch finally throw C# e.Message C# 예외 처리		B	0.85	2026-07-04	2026-07-04			csharp programming-language w3schools exceptions	https://www.w3schools.com/cs/cs_exceptions.php

CSharp Exceptions

🎯 한 줄 통찰 (One-line insight)

The try { } catch (Exception e) { } finally { } structure is functionally identical to C++'s exception handling already documented in [[CPP Exceptions]], but where C++ typically catches by REFERENCE to a specific exception type (catch (std::exception& e)) and reads its message via .what(), C# catches the generic base Exception type and reads the message via a .Message PROPERTY (no parentheses — consistent with the property-not-method pattern already confirmed for .Length in the Strings chapter); throw new ArithmeticException("...") also demonstrates that C# ships a family of ready-made, semantically-named exception classes (ArithmeticException, FileNotFoundException, IndexOutOfRangeException, TimeOutException) rather than requiring the programmer to define custom exception types from scratch for common cases. [S1]

🧠 핵심 개념 (Core concepts)

• Exception — the technical term for an error C# "throws" when something goes wrong (bad input, coding errors, unforeseen conditions). [S1]
• try { } — a block of code tested for errors during execution. [S1]
• catch (Exception e) { } — a block that runs IF an error occurs inside the paired try block; e is a variable holding the exception object. [S1]
• e.Message — a property (no parentheses) on the caught exception, describing what went wrong. [S1]
• finally { } — runs AFTER the try/catch, regardless of whether an error occurred or was caught. [S1]
• throw new ExceptionType("message") — creates and raises a CUSTOM error, using one of C#'s built-in exception classes (ArithmeticException, FileNotFoundException, IndexOutOfRangeException, TimeOutException, etc.). [S1]

📖 세부 내용 (Details)

• Unhandled error: int[] myNumbers = {1, 2, 3}; Console.WriteLine(myNumbers[10]); → System.IndexOutOfRangeException: 'Index was outside the bounds of the array.'. [S1]
• Caught with built-in message: try { ...myNumbers[10]... } catch (Exception e) { Console.WriteLine(e.Message); } → "Index was outside the bounds of the array.". [S1]
• Caught with custom message: catch (Exception e) { Console.WriteLine("Something went wrong."); } → "Something went wrong." (note: e is available but not necessarily used). [S1]
• With finally: adding finally { Console.WriteLine("The 'try catch' is finished."); } runs that line AFTER the catch block regardless of outcome. [S1]
• Custom throw: static void checkAge(int age) { if (age < 18) { throw new ArithmeticException("Access denied - You must be at least 18 years old."); } else { Console.WriteLine("Access granted - You are old enough!"); } } ... checkAge(15); → throws System.ArithmeticException: 'Access denied...'; checkAge(20); → prints "Access granted - You are old enough!". [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• C++의 예외 처리와 구조는 동일, 메시지 접근 방식이 다름: try/catch/finally 구조 자체는 [[CPP Exceptions]]에서 확인된 C++와 차이가 없지만, C++가 보통 .what() 메서드로 예외 메시지를 얻는 반면 C#은 .Message라는 프로퍼티(괄호 없음)로 접근한다는 점이 확인됨 — Strings 챕터에서 확인된 프로퍼티 vs 메서드 구분이 예외 객체에도 그대로 적용됨. [S1]
• 즉시 사용 가능한 다양한 내장 예외 클래스 제공: ArithmeticException, FileNotFoundException, IndexOutOfRangeException, TimeOutException 등 의미가 명확한 예외 클래스들이 기본 제공되어, throw할 때 매번 커스텀 예외 타입을 새로 정의할 필요가 없다는 점이 확인됨. [S1]

🛠️ 적용 사례 (Applied in summary)

나이가 18세 미만이면 ArithmeticException을 throw하고, 18세 이상이면 "Access granted"를 출력하는 checkAge() 함수 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

💻 코드 패턴 (Code patterns)

try/catch/finally with a custom throw (C#):

static void checkAge(int age)
{
    if (age < 18)
    {
        throw new ArithmeticException("Access denied - You must be at least 18 years old.");
    }
    else
    {
        Console.WriteLine("Access granted - You are old enough!");
    }
}

try
{
    checkAge(15);
}
catch (Exception e)
{
    Console.WriteLine(e.Message);  // property, no parentheses
}
finally
{
    Console.WriteLine("The 'try catch' is finished.");
}

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.85
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: C# Tutorial
• 관련 개념: CSharp User Input, CSharp Files, CPP Exceptions, CSharp Strings
• 참조 맥락: Exceptions 섹션의 유일 챕터 — Files 섹션으로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C# Exceptions - Try..Catch — https://www.w3schools.com/cs/cs_exceptions.php

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "C# Exceptions - Try..Catch" page (Astra wiki-curation, P-Reinforce v3.1 format).