Get subllist from a list in C# LINQ by removing few columns

Question

I have a list with few records. Now I want to create a new list from this existing list by removing few unwanted columns. Please guide me how to the same using LINQ C#.

Answer 1

One example, create a class that represents only properties you need.

public static async Task<CustomerItem> Example(int companyId)  
{  
    await using var context = new Context();  
    return await context  
        .Customers  
        .Select(c => new CustomerItem()  
        {  
            CompanyName = c.CompanyName,  
            ContactId = c.ContactId,  
            CustomerIdentifier = c.CustomerIdentifier  
              
        }).FirstOrDefaultAsync(x => x.CustomerIdentifier == companyId);  
}  

Or perhaps using a projection where in the following example, data comes from Vendor model and returns a sub-set of type VendorListItem.

public class VendorListItem  
{  
    public int Id { get; set; }  
    public string Name { get; set; }  
    public int NumberOfFruits { get; set; }  
  
    public static Expression<Func<Vendor, VendorListItem>> Projection  
    {  
        get  
        {  
            return x => new VendorListItem()  
            {  
                Id = x.Id,  
                Name = x.Name,  
                NumberOfFruits = x.Fruits.Count()  
            };  
        }  
    }  
}