MVC5 How to define class with only getters - asp.net-mvc

Question

I'm using VS2013 and building a simple MVC5 app with EF6 (learning C#/MVC)
The app is simple. There's a table and an SP in an SQL database that serves up sequential job nos to users via web page. This SP will also be called by a another app so the biz logic is in the SP.
The SP takes a username and returns a JobNo (PK), which is derived as Max(JobNo) + 1
I'm using DB First (as I don't currently understand enough about migrations to production with code first and nearly everything I will write has to work with existing DB's and existing SP's)
I created the model from the DB using ADO.NET and chose the table and a few SP's. This created the following:
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Manual changes to this file may cause unexpected behavior in your application.
// Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace JobNoServer.Models
{
using System;
using System.Collections.Generic;
public partial class JobNo
{
public int JobNo1 { get; set; }
public System.DateTime CreateDateTime { get; set; }
public string UserName { get; set; }
}
}
The problem I've got is that when I call the SP (user clicks "Get new Job No"), I only want to pass the username. The CreateDateTime will be current datetime (set in SP) and JobNo is determined in SP.
I tried removing the setter in class members:
public int JobNo1 { get; }
but then I get the error "must declare a body because it is not marked abstract or extern", but can't figure out how to fix this.
The other issue I have is that the controller created this Create method:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create([Bind(Include = "JobNo1,CreateDateTime,UserName")] JobNo jobNo)
{
if (ModelState.IsValid)
{
db.JobNo.Add(jobNo);
await db.SaveChangesAsync();
return RedirectToAction("Index");
}
return View(jobNo);
}
But I can't pass a job no, as it doesn't exist until after Create is called. When I remove the JobNo from the add method, I get a message saying there is no overload that takes zero params. When i look at the definition of Add it's some kind of generic class and the create view is saying job no is mandatory
public class DbSet<TEntity> : DbQuery<TEntity>, IDbSet<TEntity>, IQueryable<TEntity>, IEnumerable<TEntity>, IQueryable, IEnumerable, IInternalSetAdapter where TEntity : class
{
Could someone point me in the right direction of how to have a create method that takes just the UserName, calls the SP and gets the return value?

Answer 1

There are lot's of way to do this let's look at a few options:
//add a post method to the JobNo class (makes controller logic dead simple)...
public partial class JobNo
{
public int JobNo1 { get; set; }
public System.DateTime CreateDateTime { get; set; }
public string UserName { get; set; }
public Task Post(){
using (var db = new My Entities){
//any issues found here are purely Data access related!
db.JobNo.Add(UserName);
await db.SaveChangesAsync();
}
}
}
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create(JobNo vm)
{
if (ModelState.IsValid)
{
await vm.Post();
RedirectToAction("Index");
}
return View(vm);
}
But first you have to solve the problem of the SP wanting more than just 1 parameter right? Did you map the SP using DB first? Is JobNo class from the SP? There seems to be an "impedance mismatch"

Answer 2

By the looks of it you have your db mapped successfully, however if your db relies on Stored procedures to create PK instead of it's default functionality MVC can get a little confused, which is where you're having troubles.
Have you tried mapping the stored procedure to your context. Basically right click in your edmx diagram and 'update from database'. Instead of adding your tables(which you already did), you'll find the SP under the Stored Procedures and Functions section and add it. Done. Here's the MS how to...
If you map your stored procedure you can simply do something like the following
public JobNo myCreate( DateTime createDT, string uName)
{
int jobNo = 0;
using(Context db = new Context())
{
jobNo = db.yourSP(youParams probably uName, createDT);
}
return new JobNo() { JobNo1 = jobNo, CreateDateTime = createDT, UserName = uName};
}
Then you can reference the Create function in your question and just pass it the JobNo object you just created.
If all else fails and you can't seem to map your SP, remember you could always default to exectuting SQL directly against your context, and call your SP that way.
public JobNo myCreate( DateTime createDT, string uName)
{
int jobNo = 0;
using(Context db = new Context())
{
jobNo = db.Database.SqlQuery<int>("YourProcName #param1, #param2",
new SqlParameter("param1", createDT.toString()),
new SqlParameter("param2", uName));
}
return new JobNo() { JobNo1 = jobNo, CreateDateTime = createDT, UserName = uName};
}