Adding C# class Library to Blazor project / solution

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Summary

The issue at hand is about sharing domain objects between a .NET WebAPI project and a Blazor application by adding a C# class library to the Blazor project. Despite adding the class library project to the Blazor solution, the domain objects cannot be referenced in the Blazor app’s @code{} section.

Root Cause

The root cause of this issue is likely due to the following reasons:

  • The class library project is not properly referenced in the Blazor project
  • The namespace of the domain objects is not correctly imported in the Blazor component
  • The class library project is not compatible with the Blazor project’s target framework

Why This Happens in Real Systems

This issue occurs in real systems because of:

  • Inconsistent project configurations: Different projects in a solution may have different target frameworks, causing compatibility issues
  • Incorrect namespace imports: Failing to import the correct namespace or using an incorrect @using statement can prevent the domain objects from being recognized
  • Missing project references: Forgetting to add a reference to the class library project in the Blazor project can prevent the domain objects from being accessible

Real-World Impact

The impact of this issue includes:

  • Increased development time: Trying to resolve the issue can consume a significant amount of development time
  • Code duplication: Without being able to share domain objects, developers may duplicate code, leading to maintenance nightmares
  • Inconsistent data models: Using different data models in different projects can lead to data inconsistencies and integration challenges

Example or Code

// Domain object example
namespace MyDomainObjects
{
    public class User
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
}

// Blazor component example
@using MyDomainObjects
@code {
    private User currentUser { get; set; }
}

How Senior Engineers Fix It

Senior engineers fix this issue by:

  • Verifying project configurations: Ensuring that all projects in the solution have consistent target frameworks and configurations
  • Checking namespace imports: Confirming that the correct namespace is imported in the Blazor component using the @using statement
  • Adding project references: Adding a reference to the class library project in the Blazor project to make the domain objects accessible

Why Juniors Miss It

Junior developers may miss this issue because of:

  • Lack of experience: Inexperienced developers may not be familiar with the nuances of project configurations and namespace imports
  • Insufficient knowledge: Not understanding the importance of consistent project configurations and correct namespace imports can lead to this issue
  • Rushing through setup: Hurrying through the setup process without double-checking project configurations and references can cause this issue to be overlooked