What is SonarScanner and why use it in .NET?

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ICSM · Answer

SonarScanner is a command-line analysis tool used to 
analyze source code and send the results to SonarQube or SonarCloud.
In short: it scans your code → detects issues → reports them to Sonar.
What SonarScanner does
SonarScanner does not fix code. It:
Analyzes your source codeCalculates code metricsDetects problemsUploads results to SonarQube / SonarCloud
It works for many languages, including C# / .NET.
Why use SonarScanner in .NET projects?
In .NET (ASP.NET MVC, Web API, Console apps, etc.), SonarScanner helps you 
enforce production-grade code quality.
1. Detects real problems (not just style)
For C#/.NET it finds:
Bugs (null reference risks, unreachable code)Security vulnerabilities (SQL injection, hardcoded secrets)Code smells (too complex methods, duplicate code)Maintainability issues
Example:
if (user.IsAdmin == true || user.IsAdmin == false)
Sonar will flag this as redundant logic.
2. Enforces coding standards across teams
In large .NET projects:
Different developersDifferent coding habits
SonarScanner ensures:
Consistent code rulesStandard complexity limitsUniform naming and design patterns
This is critical for enterprise ASP.NET MVC / Web API projects.
3. Security scanning for .NET apps
Very useful for:
Public APIsAuthentication modulesChat systemsPayment or admin panels
Sonar detects:
Unsafe SQL usageWeak cryptographyInsecure deserializationAuthorization bypass risks
This goes beyond what the compiler catches.
4. Technical debt tracking
Sonar shows:
Technical debt (time to fix issues)Code coverage %Complexity trend over time
This is valuable when:
Refactoring old ASP.NET MVC 5 codeMigrating legacy .NET Framework appsMaintaining long-running systems
5. Works perfectly with CI/CD
SonarScanner integrates with:
Azure DevOpsGitHub ActionsGitLab CIJenkins
Typical pipeline:
Build → Run tests → SonarScanner → Quality Gate → Deploy
If Quality Gate fails, deployment can be blocked.
Why NOT rely only on Visual Studio?
Visual Studio:
Finds syntax errorsFinds some warnings
SonarScanner:
Finds architectural issuesFinds security risksMeasures long-term maintainability
Think of it as:
Compiler checks correctness, Sonar checks quality
When should you use SonarScanner in .NET?
You should use it if:
You have a medium or large .NET codebaseMultiple developers work on the same projectYou care about security and maintainabilityYou deploy via CI/CDYou want production-ready code
Simple mental model
SonarScanner = Inspector
SonarQube   = Dashboard
Quality Gate = Go / No-Go decision
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What is SonarScanner and why use it in .NET?

ICSM

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What SonarScanner does

Why use SonarScanner in .NET projects?

1. Detects real problems (not just style)

2. Enforces coding standards across teams

3. Security scanning for .NET apps

4. Technical debt tracking

5. Works perfectly with CI/CD

Why NOT rely only on Visual Studio?

When should you use SonarScanner in .NET?

Simple mental model

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