Sending temporary information between classes with C # 4.0 MVC 4

Assuming you have access to both systems, you could perform a ProjectA POST for ProjectB by passing a value. And in projectB you check for this value and fill in your TempData . An example would be something like this:

Project B

Cause an Ation POST to receive data from another application. If it has value, you perform redirect with TempData . It would look something like this:

   // GET: ProjetoB
    public ActionResult Index()
    {
        string valor = "";
        if (TempData["Teste"] != null)
        {
            valor = "sim";
        }
        else
        {
            valor = "não";
        }

        ViewBag.Valor = valor;
        return View();
    }

    [AllowAnonymous]
    [HttpPost]
    public ActionResult Index(string valor)
    {
        //Caso tenha valor, você preenche o TempData
        if(!string.IsNullOrEmpty(valor))
            TempData["Teste"] = 1;

        return RedirectToAction("Index");
    }

  

I am passing the value in case you want to use it in any query. But for your Model this would be irrelevant.

In this way, when updating the page TempData will have null , and thus you do not fill DropDown .

Project A

In your ProjectA you just have to POST to the correct ProjectB page like this:

<li>
    @*Na Action você deve passar o valor completo do Action POST do ProjetoB*@
    <form action="/ProjetoB/Index" method="post" id="link-cadastro">
        <input type="hidden" value="true" name="valor" />
        <a href="javascript:void(0);" onclick="$('#link-cadastro').submit()"><i class="fa fa-file-text-o"></i> Cadastro </a>
    </form>
</li>

Change the action="/ProjetoB/Index" to the path of POST ProjectB .

Note that I'm only using HTML for better understanding. However, you can use HtmlHelpers normally.

One option would be to work with cookies .

To be more exact, cookies per domain .

According to the your comment , both systems are subdomains of the same domain, meaning they all end with .site.com.br . So you can set a cookie by clicking the ProjectA link and deleting it in the Action Index of ProjectB .

It would look something like this:

ProjectA

In ProjectA you would create an Action only to create cookie and redirect to ProjectB (you can do via JS as well, it is up to you) :

public ActionResult LinkFake()
{
    HttpCookie cookie = new HttpCookie("MeuCookie");
    //Define o valor do cookie
    cookie.Value = "valorQualquer";
    //Define o Dominio do cookie
    cookie.Domain = "seudominio.com";
    //Adiciona o cookie
    Response.Cookies.Add(cookie);

    //Redireciona para o ProjetoB
    return RedirectToAction("URL PROJETO B");
}

And in your View, you'd call Action LinkFake() , like this:

<li>
    <a href="@Url.Action(LINK DA ACTIONFAKE AQUI)"><i class="fa fa-file-text-o"></i> Cadastro </a>
</li>

And in Your ProjectB you just check to see if there is that cookie or not, like this:

public ActionResult Index()
{
    HttpCookie cookie = Request.Cookies["MeuCookie"];

    if(cookie != null)
    {
        cookie.Expires = DateTime.Now.AddDays(-1d);
        Response.Cookies.Add(cookie);

        //Preencho dropdown de uma maneira
    }
    else
    {
        //Preencho dropdown de outra maneira
    }

    return View();
}

Study links:

• How to cookie domains work?
• Share cookie between subdomain and domain
• Cross-Domain Cookies

With the help of @Randrade's suggestions, I was able to reach the final result as follows:

DESIGN A

The view remains the same as the question.

VIEW

<li>
      <a href="@Url.Action(MVC.ProjetoA.Home.AbrirCadastro())"><i class="fa fa-file-text-o"></i> Cadastro </a>
</li>

The Controller is no longer in TempData and redirects to an auxiliary method in Project B.

CONTROLLER

[RequiresAuthorization]
public virtual ActionResult AbrirCadastro()
{
    Client dadosUsuario = ViewBag.User;
    return Redirect(Url.SubdomainUrl(SubdomainConstants.Register, MVC.ProjetoB.Home.IndexAuxiliar()));
}

PROJECT B

CONTROLLER

I inserted an auxiliary method to populate TempData

    [HttpGet]
    public virtual ActionResult IndexAuxiliar()
    {
        TempData["Teste"] = true;
        return RedirectToAction(MVC.ProjetoB.Home.Index());
    }

And in the main method I check if it is null or not. Thus, when there is a reload of the page, TempData will be null, thus achieving my goal.

[HttpGet]
public virtual ActionResult Index()
{
    if (TempData["Teste"] != null)
    {
        //Preencho dropdown de uma maneira
    }
    else
    {
        //Preencho dropdown de outra maneira
    }
    return View();
}