CODEWITHSUNDEEP
c#asp.net-mvcentity-framework
user4661780
user4661780

Reputation:

EF Code first, Insert record to auto generated table

I Create Two class in Models folder Like this:

Material.cs:

public class Material
{
    public int MaterialId { get; set; }
    public string Name { get; set; }

    public virtual ICollection<Project> Project { get; set; }
}

Project.cs:

 public class Project
{
    [Key]
    public int ProjectId { get; set; }
    [Required]
    public string Name { get; set; }
    public DateTime Date { get; set; }

    public ICollection<Material> Material { get; set; }

}

Entity framework code first generate a new table with name MaterialProjects in my SQL server database. I use scaffolding to generate Controllers and Views.

MaterialProjects have two Columns like this:

  1. Material_MaterialId
  2. Project_ProjectId

In 1st step I add a new project record into Projects table. In 2nd step I add a new material record into Materials table.

My question is: How can I add a record to MaterialProjects table. I cant access this entity in my code.

UPDATE: Have I do this in Materials controller create Action method?

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Create([Bind(Include = "MaterialId,Name,")] Material material)
    {
        if (ModelState.IsValid)
        {
            db.Materials.Add(material);
            //what to do here
            await db.SaveChangesAsync();
            return RedirectToAction("Index");
        }

        return View(material);
    }

Upvotes: 1

Views: 1346

Answers (2)

Yashveer Singh
Yashveer Singh

Reputation: 1977

you dont have to add in that table it will be done by EF automaticaly . The only thing you need to do id to add your entities correctly and the junction table will be filled by EF you dont have to do that . 

In controller  you can do like this  .I tested with console application.

            [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Create([Bind(Include = "MaterialId,Name,")] Material material)
    {
        if (ModelState.IsValid)
        {

         using (var ctx = new SampleDbContext())
        {
            -- here context is the DBCOntext class of your application 
            --var mat = new Material
            --{
            --    Name = "A",
            --    Project = new List<Project> {new Project {Name = "P1", Date = DateTime.Now}}
            --};

            ctx.Materials.Add(material);           
            await db.SaveChangesAsync();

        }

            return RedirectToAction("Index");
        }

        return View(material);
    }

Upvotes: 1

Developer
Developer

Reputation: 6440

EF automatically handles the Many-Many junction tables.In your case, say you want to insert a new Project with two new Material entities. You can do this by assigning the materials collection to the Material collection of the new Project entity. EF will inset a new Project and two new materials and will automatically populate the junction table as well

Updating after OP updates the question Hoping that you have already have the Project entity inserted (say, the id of that project is 100). So while adding new Material entity:

var proj = context.Projects.Find (100);
newMaterialObject.Projects.Add (proj);
context.SaveChanges();

Upvotes: 0

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