Getting Error An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter

Question

Getting Error after Update data into database

The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult UpdateChain(Int32, HCIBE.Models.chain)' in 'HCIBE.Controllers.ChainsController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.

Here is My Controller

    [HttpGet]
    public ActionResult UpdateChain(int? id)
    {
        chain objchain = db.chains.Find(id);
        if (objchain == null)
        {
            return HttpNotFound();
        }
        return View(objchain);
    }

    [HttpPost]
    public ActionResult UpdateChain(int id, [Bind(Include = "name,code,username,password,updated_by,updated_on")] chain chain)
    {
        chain _objchain = db.chains.Find(id);
        try
        {
        if(ModelState.IsValid)
        {
            _objchain.code = chain.code;
            _objchain.name = chain.name;
            _objchain.username = chain.username;
            _objchain.password = chain.password;
            _objchain.updated_by = Convert.ToInt32("1");
            _objchain.updated_on = DateTime.Now;

            db.Entry(_objchain).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        }
        catch (Exception Ex)
        {
            ModelState.AddModelError("", "Unable to update data");
        }
        return View(_objchain);
    }

View

@using (@Html.BeginForm("UpdateChain", "Chains", FormMethod.Post))
{

<div class="form-horizontal">
    <hr />
    <div class="form-group">
        <label class="col-sm-2 control-label">
            Select Chain
        </label>
        <div class="col-md-3">
            @Html.DropDownList("ddlchainname", (SelectList)ViewData["chain_name"],"Select Chain", new { onchange = "Action(this.value);", @class = "form-control" })
        </div>
        <label class="control-label">
            or @Html.ActionLink("Add New", "Create")

        </label>
    </div>
    <div class="form-group">
        <label class="col-sm-2 control-label">
            Chain Name
        </label>
        <div class="col-md-3">
            @Html.TextBox("ChainName", null, new { @class = "form-control" })
        </div>
        <label class="col-sm-2 control-label">
            Username
        </label>
        <div class="col-md-3">
            @Html.TextBox("username", null, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        <label class="col-sm-2 control-label">
            Chain Code
        </label>
        <div class="col-md-3">
            @Html.TextBox("ChainCode", null, new { @class = "form-control" })
        </div>
        <label class="col-sm-2 control-label">
            Password
        </label>
        <div class="col-md-3">
            @Html.Password("password", null, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Update" onclick="UpdateChain()" class="btn btn-default" />
        </div>
    </div>
</div>
}

<script type="text/javascript">
    function UpdateChain(){
        var _vddlChainID = $("#ddlchainname").val();
        alert("Your Selected ID = " + _vddlChainID);
        $.ajax({
            url: '@Url.Action("UpdateChain", "Chains")',
            type: "POST",
            data: { "id": _vddlChainID }
        });
    }
</script>

Through Dropdown Selection i Fill all textboxes, when i submit form then i get Error.

Routing

    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
        );
    }

Model

public partial class chain
{
    public chain()
    {
        this.templates = new HashSet<template>();
        this.hotels = new HashSet<hotel>();
    }

    public long chain_id { get; set; }
    public string name { get; set; }
    public string code { get; set; }
    public string username { get; set; }
    public string password { get; set; }
    public long created_by { get; set; }
    public System.DateTime created_on { get; set; }
    public Nullable<long> updated_by { get; set; }
    public Nullable<System.DateTime> updated_on { get; set; }

    public virtual ICollection<template> templates { get; set; }
    public virtual ICollection<hotel> hotels { get; set; }
}

Solution

You are passing an object of chain but you have not added value of id in it anywhere. You need to set value of id and add it in chain object.

Comments

[Origin]

Care to show your routings? I believe that's the problem. The default route requires an ID.

[Admin]

You have either omitted some code or not much makes sense here. Why are you using AJAX to post as well as submitting the form at the same time (you are making 2 calls - one passing the id value (AJAX) which does nothing and the other passing chain (SUBMIT) without the id

[ANJYR]

i haven't too much idea about MVC, may be my way of work is wrong so plz. guide me to correct this. thanks

[Admin]

You have numerous errors. For instance you are rendering a textbox with name="ChainName" but your model does not include a property with the namae ChainName` (at least not according to your [Bind(Include= ...)] list. Your [Bind(Include= ...)] also includes properties for which you are not even rendering a control. But the main issue is your making 2 calls to the controller (the javascript is not neccessary). Please post you model so I can guide you.

[ANJYR]

[Bind(Include=.....)] in this context what we pass, Html control name or table column name? i also update my question with model.

[Admin]

It optional, but yes. If you use it it needs to match the names of your controls which must match the names of you properties (which it currently doesn't), but you should be using a view model in this case. Can you please explain the purpose of the dropdown and what is the script for onchange = Action(this.value)

[ANJYR]

onchange=Action(this.value) Method call Controller through AJAX to bind all textbox data according to dropdown selection . you can check this stackoverflow.com/questions/26031197/…

[Admin]

Let us continue this discussion in chat.

[ANJYR]

As id i passing dropdown selectedvalue, so how i pass my dropdown value there. @Url.Action("UpdateChain", "Chains",new {id= DropdownValue }) i don't know.

[ANJYR]

I don't know how to pass dropdown selected value into any hidden field or any where in view.

[Mairaj Ahmad]

Change this line @Url.Action("UpdateChain", "Chains") to @Url.Action("UpdateChain", "Chains",new {id=_vddlChainID })

[ANJYR]

it's not working... The name '_vddlChainID' does not exist in the current context.

[Admin]

This is not necessary, the id value is already passed using data: { "id": _vddlChainID }. The problem is 2 calls are being made to the controller.

[Twix]

you can directly pass it to the method like this string ddlchainname where string is the type of the value being passed by dropdown ddlchainname is the name of the dropdown