Send JSON to Server (ASP.NET MVC4)

Question

I have JSON:

[{"id":1,"user_id":"8","project_id":"1","mode":3},{"id":1,"user_id":"8","project_id":"2","mode":1},{"id":1,"user_id":"8","project_id":"3","mode":1}] 

So, I try to send it to server:

$.ajax({
 url : "User/Permissions_Set",
 dataType: 'json',
 type: 'POST',
 data: JSON.stringify(permissions_JSON),
 success: function (data) {
 console.log(data);
 }
 });

On Serverside:

[HttpPost]
 public void Permissions_Set(List<Permission> permissions_JSON)
 {
 foreach (var permission_from_view in permissions_JSON)
 {
 var permission_from_db = db.Permissions.Where(prm => prm.project_id == permission_from_view.project_id && prm.user_id == permission_from_view.user_id).FirstOrDefault();
 permission_from_db.mode = permission_from_view.mode;
 }
 db.SaveChanges();
 }

But I have error near "foreach": Object reference not set to an instance of an object.

I think problem with List permissions_JSON, but my model "Permission" has properties "id", "user_id", "project_id", "mode"

Please, advice, how I can recieve JSON from client on serverside.

Update:

Now I've changed jquery, and it return successfull result. But anyway I can't work with permissions_JSON. So, is it possible work with permissions_JSON not like "List", but like JSON. Could, you, please anybody advice how to recieve it, and work with it in C#...

Thanks in advance.

• Umesh Sehta: can you show Permission class?
• annoirq: public class Permission { public int id { get; set; } public int user_id { get; set; } public int project_id { get; set; } public int mode { get; set; } [ForeignKey("user_id")] public virtual User User { get; set; } [ForeignKey("project_id")] public virtual Project Project { get; set; } }
• Cristi Pufu: try: data: { permissions_JSON: JSON.stringify(permissions_JSON) }
• Yogurt The Wise: try it in reverse, send a list of items, from server thru ajax to the client javascript. Debug and see what the string looks like, may give you an idea what is wrong or missing.
• annoirq: hi, thanks, now error disappear, but now permissions not saved in database, and console.log(data) brings nothing, that means that ajax is not succeed

Answer 1

Edit: Try doing it this way:

var bob = {permissions_JSON:[{ id: 1, user_id: 8, project_id: 1, mode: 3}]};
request.permissions_JSON = bob;
$.ajax({
 url: "Home/Permissions_Set",
 dataType: 'json',
 type: 'POST',
 contentType: 'application/json;',
 data: JSON.stringify(bob),
 success: function (data) {
 console.log(data);
 }
});

create a new object. Attach the collection to that object. Make sure the collection on the object as the same name as your parameter.

• annoirq: hi, thanks, now error disappear, but now permissions not saved in database, and console.log(data) brings nothing, that means that ajax is not succeed
• PaulBinder: This should now work 100% with the edits I just made. NOTE: your success methods will never have data as you created a void method. Voids have no return values.