System.InvalidOperationException: 'An error was generated for warning 'Microsoft.EntityFrameworkCore.Query.InvalidIncludePathError'

Question

I get this error:

System.InvalidOperationException: 'An error was generated for warning 'Microsoft.EntityFrameworkCore.Query.InvalidIncludePathError': Unable to find navigation ' ApplicationUser' specified in string based include path ' ApplicationUser'. This exception can be suppressed or logged by passing event ID 'CoreEventId.InvalidIncludePathError' to the 'ConfigureWarnings' method in 'DbContext.OnConfiguring' or 'AddDbContext'.'

from my repository class (this is the function):

public T GetFirstOrDefault(Expression<Func<T, bool>> filter, string? includeProperties = null, bool tracked = true)
{
    if (tracked)
    {
        IQueryable<T> query = dbSet;

        query = query.Where(filter);

        if (includeProperties != null)
        {
            foreach (var includeProp in includeProperties.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
            {
                query = query.Include(includeProp);
            }
        }

        return query.FirstOrDefault();
    }
    else
    {
        IQueryable<T> query = dbSet.AsNoTracking();

        query = query.Where(filter);

        if (includeProperties != null)
        {
            foreach (var includeProp in includeProperties.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
            {
                query = query.Include(includeProp);
            }
        }

        return query.FirstOrDefault();
    }
}  

Where did I make a mistake? If anyone knows, then please help me solve my problem

Answer 1

You need to check on the following points to fix the given error :

• Check your code for typos in entity names, property names, or include paths can cause such issues.
• Make sure you are using a compatible and up-to-date version of EF Core for your project.
• Ensure that the entity type T being used in the GetFirstOrDefault method has a navigation property named 'ApplicationUser' if you are specifying it in the includeProperties parameter.
• Check the value you are passing to the includeProperties parameter. Make sure there are no extra spaces, typos, or incorrect property names in the comma-separated string. It should match the navigation property names of the entity T.
• Ensure that the Entity Framework Core model configuration for your entity T is correctly defining the navigation properties. If you are using attributes verify that the navigation property is correctly mapped.
• Check the DbContext class associated with your application and make sure it has DbSet properties for all relevant entities, including ApplicationUser if that's what you are trying to include.