Return Succes Message After Delete/Update/create - ajax

Question

This is my GesAgence Page action :
public ActionResult GesAgence()
{
var test = new Models.J2VEntities();
return View(test.agence);
}
This is my Action for Deleting :
public ActionResult DeleteAg(string id)
{
Models.J2VEntities entity = new Models.J2VEntities();
Models.agence model = (from p in entity.agence
where p.Idag == id
select p).SingleOrDefault();
//Sauvgarde ds la BD
entity.agence.DeleteObject(model);
entity.SaveChanges();
return View("gesAgence");
}
So i'm wondring how to return Succes message after deleting(i tried with TempData but didn't succed because my gesAgence must return model not TempData).

Answer 1

You can use Ajax to call your controller from your viewpage and pop up the message whatever your controller returned, try something like this.
Script on your view page.
function onDeleteAg (id) {
var answer = confirm("Are you sure you want to delete AG ?")
if (answer) {
$.ajax(
{
type: "Get",
url: '<%= Url.Action("DeleteAg","YourControllerName") %>',
data: { agId: id },
success: function (data) {
//HERE--data is the message you that your controller DeleteAg method will return after it's called. you need to do something here to display this message(data) anywhere you want to . something like below.
alert(data);
},
error: (function () { alert("Error! Ag was not deleted." ); })
});
}
};
Method on your controller.
public string DeleteAg(string agId)
{
try{
Models.J2VEntities entity = new Models.J2VEntities();
Models.agence model = (from p in entity.agence
where p.Idag == id
select p).SingleOrDefault();
//Sauvgarde ds la BD
entity.agence.DeleteObject(model);
entity.SaveChanges();
}
catch(Exception ex)
{
return "AG has not been deleted successfully;
}
return "AG has been deleted successfully;
}

Answer 2

you can call this method via ajax and return JsonResult instead of ActionResult, by looking result you can show message to user.
public JsonResult DeleteAg(string id)
{
Models.J2VEntities entity = new Models.J2VEntities();
Models.agence model = (from p in entity.agence
where p.Idag == id
select p).SingleOrDefault();
//Sauvgarde ds la BD
entity.agence.DeleteObject(model);
entity.SaveChanges();
var json = new
{
success = true
};
return Json(json);
}

Answer 3

You can set Success to ViewBag
public ActionResult DeleteAg(string id)
{
Models.J2VEntities entity = new Models.J2VEntities();
Models.agence model = (from p in entity.agence
where p.Idag == id
select p).SingleOrDefault();
//Sauvgarde ds la BD
entity.agence.DeleteObject(model);
entity.SaveChanges();
ViewData["Success"] = true;
return View("gesAgence");
}
in view
#if(ViewData["Success"] != null && (bool)ViewData["Success"]){
<script>alert("Sucess!");</script>
}
This is my view :
<% if(ViewData != null && ViewData["Success"] != null && (bool)ViewData["Success"]){ %>
<script type="text/javascript"> alert("Sucess!");</script>
<% } %>
<div class="clear">
</div>
<div id="main">
<h1> Demande preinscrit</h1>
<ul class="listing">
<% foreach (var item in Model) { %>
<li>
<div class="listinfo">
<h3>
<%: Html.DisplayFor(modelItem => item.Nomag) %>
</h3>
<p>
<%: Html.DisplayFor(modelItem => item.Idag) %>
</p>
<span class="price"> <%: Html.DisplayFor(modelItem => item.Adrag) %> <%: Html.DisplayFor(modelItem => item.Vilag) %> <%: Html.DisplayFor(modelItem => item.Gov) %></span> <span class="media">Tel : <%: Html.DisplayFor(modelItem => item.Telag) %> |</span> <%: Html.DisplayFor(modelItem => item.Mailag) %>
</div>
<div class="listingbtns">
<span class="listbuttons"><%: Html.ActionLink("Bloque", "Bloque", new {id= item.Idag}) %> </span>
<span class="listbuttons"><%: Html.ActionLink("Supprime", "DeleteAg", new { id = item.Idag })%></span>
</div>
<div class="clear">
</div>
</li>
<% } %>
i got this error : System.NullReferenceException: Object reference not set to an instance of an object on this line <% foreach (var item in Model) { %>.