asp.net mvc 5-将ViewBag项传递回控制器

Question

I am trying to pass a ViewBag item from my view back into the post method for that view but I am having difficulty.

This is a simplified version of my methods:

public ActionResult CreateGame(int id)
{
    var selPlayer = db.Players.Find(id);

    if (selPlayer == null)
    {
        return HttpNotFound();
    }

    ViewBag.SelPlayerId = selPlayer.PlayerID;

    PlayerGame newGame = new PlayerGame ();

    return View(newGame);
}

[HttpPost]
public ActionResult CreateGame(PlayerGame newGame)
{
    newGame.GameTitle = newGame.GameTitle;
    newGame.GameNotes = newGame.GameNotes;
    newGame.PlayerID = newGame.PlayerID;

    return RedirectToAction("PlayerView");
    return View(newGame);
}

This is a simplified version of my View:

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()
    <div class="form-horizontal">
        <fieldset>

            <div class="editor-label">
            @Html.LabelFor(model => model.GameTitle)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.GameTitle)
        </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.GameNotes)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.GameNotes)
            </div>

            @Html.HiddenFor(model => model.PlayerID, new { PlayerID = ViewBag.SelPlayerId })
            <p>
                <input type="submit" value="Submit Game" class="btn btn-info" />
            </p>
        </fieldset>
        </div>
        }

In the POST method you can see I am trying to set the PlayerID equal to the player Id that I am passing through as ViewBag.SelPlayerID but when I look at the values that are being passed through in the debugger the id is always equal to 0 which is not right as the player I am using to test has an id of 1.

My question is how can I set the player ID for the new game I am creating equal to the player ID I am passing through as the ViewBag item, or alternatively if there is an easier way of doing this that I have overlooked.

Note: The player id is a foreign key in my Player Game model:

//Foreign Key for Player
        public int PlayerID { get; set; }

        [ForeignKey("PlayerID")]
        public virtual Player Player { get; set; }

Answer 1

You usage of new { PlayerID = ViewBag.SelPlayerId } in the @Html.HiddenFor() method is setting a html attribute, not the value of the property.

If you inspect the html your generating it will be

<input type="hidden" name="PlayerID" PlayerID="1" value="0" />

Change your GET method to set the value of the property in the model (and delete the ViewBag property)

PlayerGame newGame = new PlayerGame() { PlayerID = selPlayer.PlayerID };
return View(newGame);

and in the view use

@Html.HiddenFor(m => m.PlayerID)

Answer 2

This:

@Html.HiddenFor(model => model.PlayerID, new { PlayerID = ViewBag.SelPlayerId })

Is creating a hidden element, bound to model.PlayerID , but with a custom Html attribute of PlayerID , you are getting 0 as thats the default value for int and you are not setting it on the model.

Based on your (simplified) code sample, you should be able to set the model PlayerID to your selected value in the get action on the controller:

newGame.PlayerID = selPlayer.PlayerID

And then

@Html.HiddenFor(m => m.PlayerID)

---

If for some reason you have to use ViewBag , and can't populate it on the model as above you can use @Html.Hidden instead to ensure the value comes back in.

@Html.Hidden("PlayerID", ViewBag.SelPlayerId)

Will result in:

<input type="PlayerID" value="1" />

Which should model bind back to the model. If that's not an option and to do it more manually, you can change the first parameter to something like "SelectedPlayerID" and then you can either pull out in from Request in the controller post action.

Answer 3

只是试图在CSHTML视图page.On回传此使用viewbag alone.Set隐藏式元素你会得到你的argument.This您的玩家ID将工作，如果你使用的是输入型提交

<input type="hidden" id="PlayerID" name="PlayerID" value="@ViewBag.SelPlayerId"/>