将静态值分配给模型中的字段

Question

My view has the user enter in values into a form. These values get passed to the controller, in which I use dbset to create the new row in my table. There is one field that serves as a flag for that row, which I don't want the user to define/ even know exists. My question is, how can I assign data to this field and have it passed to the controller without the user having to provide input? In this case, I want the ACTION_TYPE field to be assigned the value/string "Add".

View

@using (Html.BeginForm()) {
@Html.ValidationSummary(true)

var action = Html.HiddenFor(model => model.ACTION_TYPE.ToString());
string val = "Add";
if (action == null){
    action = MvcHtmlString.Create(val);
}

Controller

 public ActionResult Create()
    {
        return View();
    }

    //
    // POST: /Table8/Create

    [HttpPost]
    public ActionResult Create(HOLIDAY_DATE_TABLE holiday_date_table, tbl8_update_transactions tbl8_update_transaction)
    {
        if (ModelState.IsValid)
        {
            db.HOLIDAY_DATE_TABLE.Add(holiday_date_table);
            db.SaveChanges();
            db.tbl8_update_transactions.Add(tbl8_update_transaction);
            db.SaveChanges();
            return RedirectToAction("../Billing/HolidayDateTable");
        }
        return View(holiday_date_table);
    }

Tables

 CREATE TABLE HOLIDAY_DATE_TABLE
 (
 HID INT IDENTITY PRIMARY KEY,
 TABLE_NUMBER nchar(2) NOT NULL,
 HOLIDAY_DATE nchar(8) NOT NULL,
 FIELD_DESCRIPTION nVARchar(43) NULL,
 ACTION_TYPE nchar(6) NULL
 );


 CREATE TABLE tbl8_update_transactions
 (
 TID INT IDENTITY PRIMARY KEY,
 TABLE_NUMBER nchar(2) NOT NULL,
 HOLIDAY_DATE nchar(8) NOT NULL,
 FIELD_DESCRIPTION nVARchar(43) NULL,
 ACTION_TYPE nchar(6) NULL,
 HID int,
 FOREIGN KEY (HID) REFERENCES HOLIDAY_DATE_TABLE (HID) ON DELETE CASCADE
 );

Answer 1

If the user isn't inputting this data then it doesn't belong in the form being submitted by the user. Remove it from the view entirely and set it in the server-side code. One simple way to do this could be in the controller action:

// completely guessing on types/models here, but you should get the idea...
holiday_date_table.ActionType = "Add";
db.HOLIDAY_DATE_TABLE.Add(holiday_date_table);
db.SaveChanges();

Or you can even set it by default in the model itself (which is ideally where logic like this goes), the design of which is going to depend very heavily on your model structure. A default value might be set in a constructor, or late-bound in a property, or perhaps by separating the concepts of "adding" vs. "editing" into their own models.

Either way, it shouldn't be in the view. Even as a hidden field, any user can change that value whenever they like. The only way for your code to genuinely control the value is to keep it server-side.

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As an aside, any time you declare a server-side variable in a view then you're most likely doing something wrong. Views shouldn't have business logic, they just bind a UI to a model. The logic really belongs in the model.