NuGet Package Management

What is NuGet?

NuGet is the package manager for .NET. It's like npm for Node.js, pip for Python, or Maven for Java. NuGet lets you easily add third-party libraries to your projects without manually downloading and managing DLLs.

Why Use NuGet?

• Save Time: Don't reinvent the wheel—use proven libraries
• Easy Updates: Update packages with a single command
• Dependency Management: Automatically handles package dependencies
• Version Control: Lock to specific versions for stability
• Community: Access to 350,000+ packages
• Open Source: Most packages are free and open source

Finding Packages

NuGet.org - The Official Package Repository

Visit https://www.nuget.org to search for packages.

Popular NuGet Packages

Package	Purpose	Downloads
Newtonsoft.Json	JSON serialization/deserialization	3B+
Microsoft.EntityFrameworkCore	Object-Relational Mapper (ORM)	500M+
Serilog	Structured logging	200M+
AutoMapper	Object-to-object mapping	300M+
FluentValidation	Input validation	150M+
Dapper	Micro-ORM for SQL	200M+

Installing Packages

Using the dotnet CLI

# Install latest version
dotnet add package Newtonsoft.Json

# Install specific version
dotnet add package Serilog --version 3.1.1

# Install to specific project
dotnet add src/InvenTrack.Api package Microsoft.EntityFrameworkCore

# Install prerelease version
dotnet add package SomePackage --prerelease

Using Visual Studio

1. Right-click on your project in Solution Explorer
2. Select "Manage NuGet Packages"
3. Click the "Browse" tab
4. Search for the package
5. Click "Install"

Using VS Code

VS Code doesn't have a built-in NuGet UI, but you can:

• Use the integrated terminal with dotnet add package
• Install the "NuGet Package Manager" extension
• Manually edit the .csproj file

Manual Installation (Editing .csproj)

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
    <PackageReference Include="Serilog.AspNetCore" Version="8.0.0" />
  </ItemGroup>

</Project>

After editing, run dotnet restore to download the packages.

Managing Packages

Viewing Installed Packages

# List all packages in current project
dotnet list package

# List packages in entire solution
dotnet list package

# Show package dependency tree
dotnet list package --include-transitive

Updating Packages

# Check for outdated packages
dotnet list package --outdated

# Update to latest version (edit .csproj manually or use dotnet add)
dotnet add package Newtonsoft.Json

# Update to specific version
dotnet add package Serilog --version 3.1.1

Removing Packages

# Remove package
dotnet remove package Newtonsoft.Json

# Remove from specific project
dotnet remove src/InvenTrack.Api package Serilog

Understanding Package Versions

Semantic Versioning (SemVer)

NuGet packages follow Semantic Versioning: MAJOR.MINOR.PATCH

3.1.2
│ │ │
│ │ └─ PATCH: Bug fixes (backward compatible)
│ └─── MINOR: New features (backward compatible)
└───── MAJOR: Breaking changes

Version Ranges

Notation	Meaning	Example
3.1.2	Exact version	Only 3.1.2
3.1.*	Latest patch	3.1.0, 3.1.1, 3.1.2, etc.
[3.1.0, 4.0.0)	Range (inclusive, exclusive)	3.1.0 to 3.9.9
(3.1.0,)	Greater than	Anything above 3.1.0

Package Restore

When you clone a repository or pull changes, you need to restore packages:

# Restore packages for current project/solution
dotnet restore

# Restore with specific sources
dotnet restore --source https://api.nuget.org/v3/index.json

# Force re-download (clear cache)
dotnet restore --force

Package Cache Location

NuGet caches downloaded packages to speed up restores:

• Windows: %userprofile%\.nuget\packages
• macOS/Linux: ~/.nuget/packages

# Clear all NuGet caches
dotnet nuget locals all --clear

# Clear only global packages cache
dotnet nuget locals global-packages --clear

Essential Packages for InvenTrack

Database Access

# Core EF package
dotnet add package Microsoft.EntityFrameworkCore

# SQL Server provider
dotnet add package Microsoft.EntityFrameworkCore.SqlServer

# Design-time tools (migrations)
dotnet add package Microsoft.EntityFrameworkCore.Design

# EF Core CLI tool (global)
dotnet tool install --global dotnet-ef

Logging

# Serilog for ASP.NET Core
dotnet add package Serilog.AspNetCore

# Sinks (output destinations)
dotnet add package Serilog.Sinks.Console
dotnet add package Serilog.Sinks.File

Validation

dotnet add package FluentValidation
dotnet add package FluentValidation.AspNetCore

Object Mapping

dotnet add package AutoMapper
dotnet add package AutoMapper.Extensions.Microsoft.DependencyInjection

Authentication & Authorization

# ASP.NET Core Identity
dotnet add package Microsoft.AspNetCore.Identity.EntityFrameworkCore

# JWT Bearer Authentication
dotnet add package Microsoft.AspNetCore.Authentication.JwtBearer

API Documentation

dotnet add package Swashbuckle.AspNetCore

Testing

# xUnit (testing framework)
dotnet add package xunit
dotnet add package xunit.runner.visualstudio

# Moq (mocking library)
dotnet add package Moq

# FluentAssertions (better assertions)
dotnet add package FluentAssertions

Security Considerations

Checking for Vulnerabilities

# Check for vulnerable packages
dotnet list package --vulnerable

# Check for outdated packages
dotnet list package --outdated

Package Source Configuration

You can configure custom NuGet sources in nuget.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <clear />
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
    <add key="MyCompanyFeed" value="https://pkgs.dev.azure.com/mycompany/_packaging/myfeed/nuget/v3/index.json" />
  </packageSources>
</configuration>

Creating Your Own NuGet Packages

You can package your own libraries and share them on NuGet.org or private feeds.

Step 1: Configure Package Metadata

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    
    <!-- Package Metadata -->
    <PackageId>InvenTrack.Core</PackageId>
    <Version>1.0.0</Version>
    <Authors>Your Name</Authors>
    <Company>InvenTrack Inc.</Company>
    <Description>Core business logic for InvenTrack inventory system</Description>
    <PackageLicenseExpression>MIT</PackageLicenseExpression>
    <PackageProjectUrl>https://github.com/yourname/inventtrack</PackageProjectUrl>
    <RepositoryUrl>https://github.com/yourname/inventtrack</RepositoryUrl>
    <PackageTags>inventory;erp;business</PackageTags>
  </PropertyGroup>

</Project>

Step 2: Pack the Project

# Create NuGet package (.nupkg file)
dotnet pack --configuration Release

# Output will be in bin/Release/
# Example: InvenTrack.Core.1.0.0.nupkg

Step 3: Publish to NuGet.org

# Get API key from nuget.org
# Then push package
dotnet nuget push bin/Release/InvenTrack.Core.1.0.0.nupkg --api-key YOUR_API_KEY --source https://api.nuget.org/v3/index.json

Troubleshooting Common Issues

Issue: Package Not Found

Cause: Package name typo or package doesn't exist.

Solution:

• Verify package name on NuGet.org
• Check spelling and capitalization
• Ensure you're using the correct package source

Issue: Version Conflict

Cause: Two packages require different versions of the same dependency.

Solution:

• Update all packages to latest versions
• Use dotnet list package --include-transitive to see dependency tree
• Manually specify version in .csproj

Issue: Restore Failed

Cause: Network issues, corrupted cache, or authentication problems.

Solution:

• Clear NuGet cache: dotnet nuget locals all --clear
• Check internet connection
• Verify package source is accessible
• Try dotnet restore --force

Key Takeaways

• NuGet is the package manager for .NET
• Search for packages on NuGet.org
• Install packages with dotnet add package PackageName
• Packages are listed in <PackageReference> in .csproj
• Semantic Versioning: MAJOR.MINOR.PATCH
• Use exact versions for production apps
• dotnet restore downloads packages (usually automatic)
• Check for vulnerabilities with dotnet list package --vulnerable
• Essential InvenTrack packages: EF Core, Serilog, FluentValidation, AutoMapper
• Create your own packages with dotnet pack
• NuGet caches packages in ~/.nuget/packages
• Clear cache with dotnet nuget locals all --clear