ASP.NET MVC Data Repository

Question

I am getting an error message that says:

"No mapping exists from object type <>f__AnonymousType6`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] to a known managed provider native type."

public List<Product> GetCategoryProducts(int catID)
{
    string sql = @"select p.ProductID, p.ItemName, p.ImageName
    from Product p, ProductCategory pc
    where p.ProductID = pc.ProductID
    and pc.CategoryID = @catID
        order by p.ItemName";

    List<Product> products = db.Products.SqlQuery(sql, new { catID }).ToList();
    return products;
}

I am not sure why I am getting this error

It's explained in SqlQuery method help. But why bother with SQL, this is quite simple LINQ To Entities query, you are not using the benefits of your ORM. — Ivan Stoev
– Ivan Stoev, Commented Apr 21, 2017 at 19:05
Please do not delete your previous question and change it to a new one. Either create a new question, or edit you question to include the additional question information (leaving the old one). By deleting the question, you are preventing anyone else from gaining benefit from your question. It's also confusing why there are answers that do not seem to address the current question. — Erik Funkenbusch
– Erik Funkenbusch, Commented Apr 21, 2017 at 19:43

Christos · Accepted Answer · 2017-04-21 19:35:48Z

2

You should do two things a) change the return type of your query, SqlQuery<Product> and b) pass the parameter catID to your query:

var products = db.Products
                 .SqlQuery<Product>(sql,new SqlParameter("catID", catID))
                 .ToList();

I am setting pc.CategoryID = @catID.

Indeed you declare a parameterized query, but you don't pass a value for your parameter. The following is just a string:

@"select p.ProductID, p.ItemName, p.ImageName
from Product p, ProductCategory pc
where p.ProductID = pc.ProductID
and pc.CategoryID = @catID 
order by p.ItemName"

You don't set there any value for the CategoryID. This is the job of SqlQuery method, that would handle this provided that you pass one.

edited Apr 21, 2017 at 19:35

answered Apr 21, 2017 at 19:02

Christos

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2 Comments

Timothy Wong Over a year ago

I added List<Product> products = db.Products.SqlQuery(sql, new { catID }).ToList(); to fix the scalar variable error

Timothy Wong Over a year ago

now Im getting this error: No mapping exists from object type <>f__AnonymousType6`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] to a known managed provider native type.

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