Persistent data in an ASP.NET MVC controller

I want to use the same view to insert and update data in a database.

When I am in the "edit mode", I need to know what are the values before and after the edition (to know what has changed and perform operations based on that).

I cannot store the "before edit" data in the model, as there are not mapped and I cannot store that data in the controller as a new instance is created between get and post.

For instance I have no other idea that using a static class or hidden fields but it doesn't sound to me to be a good practice.

How to achieve that in a proper way?

Thanks

You can see the older data in
var data = context.DEMO_MAST.Where(x => x.ID == model.ID).FirstOrDefault(); and new data in Model and just using If Condition you can do AddEdit both things in single method.

AddEdit Method

 public int AddOrEdit(DEMO_MAST model)
            {
                try
                {
                    var data = context.DEMO_MAST.Where(x => x.ID == model.ID).FirstOrDefault();
                    if (data == null)
                    {
                        model.CREATED_ON = DateTime.Now;
                        this.context.DEMO_MAST.Add(model);
                    }
                    else
                    {
                        model.MODIFIED_ON = DateTime.Now;
                        this.context.Entry(data).CurrentValues.SetValues(model);
                    }
                    int flg = this.context.SaveChanges();
                    return flg;
                }
                catch (Exception ex)
                {
                    return 0;
                }
            }

Find

public DEMO_MAST Find(int ID)
{
  return context.DEMO_MAST.where(x=>x.ID==ID).FirstorDefault();
}

Controller

[HttpGet]
public ActionResult Index(int ID)
{
   DEMO_MAST model=new DEMO_MAST();
  if(ID>0)
  {
     model=Find(ID);   
  } 
return View(model);
}

[HttpPost]
public ActionResult Index(DEMO_MAST model)
{
  if(ModelState.IsValid)
  {
     int i = AddEdit(model); 
     if(i>0) 
     {
       ViewBag.Message="Record AddEdit Successfully";
     }
     else
     {
       ViewBag.Message="Error";
     }
  }
return View(model);
}

So when you run your application simple Index() view is display.

Index view for get data

   using (Html.BeginForm("Index", "Home"))
    {
        <div class="row">
            <div class="col-md-6 col-sm-3">
            </div>
            <div class="col-md-6 col-sm-9">
                <div id="sample_6_filter" class="dataTables_filter">
                    <label>
                        @Html.TextBox("ID", ViewBag.ID == null ? "" : (string)ViewBag.ID, new { @class = "form-control input-inline", placeholder = "ID" })
                        <button class="btn green-haze" type="submit" id="submit">
                            <i class="fa fa-search"></i>
                        </button>
                    </label>
                </div>
            </div>
        </div>
    }
    @using (Html.BeginForm("Index", "Home", FormMethod.Post))
    {
        @Html.HiddenFor(x => x.ID)
        @Html.HiddenFor(x => x.CREATED_ON)
        <div class="form-horizontal">
            
            <div class="form-group">
                <label class="control-label col-sm-4">Name</label>
                <div class="col-sm-5">
                    @Html.TextBoxFor(a => a.Name, new { @class = "form-control", @maxlength = "50" })
                </div>
                <div class="col-sm-3 text-danger">
                   
                </div>
            </div>
 <div class="form-group">
       <div class="col-sm-12 text-center">
                <button type="submit" name="command" value="createUser" class="btn btn-lg btn-green hvr-underline-from-center">Submit</button>
       </div>
  </div>
    }

You need to enter ID or any Uniq field of your database for get result in View. When you click on button the [HttpGet] Index method will be called and display records in view.

And after that you can modify your data.Click on submit so it will go for
'[HttPost] Index' remain things done automatically as per above code and methods.

Now you just need to set your data in view.. that's it.
Hope you understand!! Enjoy!!