How can I write dynamic data to page layout in MVC 3 Razor?

Question

I have MVC 3 C# project with Razor engine. What are the ways and, I guess, the best practices to write dynamic data to the _Layout.cshtml?

For example, maybe I\'d like

Answer 1

The default internet application created by visual studio use _LogOnPartial.cshtml to do exactly this.

The user Name value is set in the LogOn action of the HomeController

Code for _LogOnPartial.cshtml

@if(Request.IsAuthenticated) {
    Welcome @User.Identity.Name!
    [ @Html.ActionLink("Log Off", "LogOff", "Account") ]
}
else {
    @:[ @Html.ActionLink("Log On", "LogOn", "Account") ]
}

User.Identity is part of the aspnet Membership provider.

Code for the _Layout.cshtml

    
    
    
    
    


    

        

            

                
Test
            
            

                @Html.Partial("_LogOnPartial")
            
            

                

                
            
        
        

            @RenderBody()
        
        

        
    

Code for the AccountController Logon Action

[HttpPost]
        public ActionResult LogOn(LogOnModel model, string returnUrl)
        {
            if (ModelState.IsValid)
            {
                if (Membership.ValidateUser(model.UserName, model.Password))
                {
                    FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
                    if (Url.IsLocalUrl(returnUrl) && returnUrl.Length > 1 && returnUrl.StartsWith("/")
                        && !returnUrl.StartsWith("//") && !returnUrl.StartsWith("/\\"))
                    {
                        return Redirect(returnUrl);
                    }
                    else
                    {
                        return RedirectToAction("Index", "Home");
                    }
                }
                else
                {
                    ModelState.AddModelError("", "The user name or password provided is incorrect.");
                }
            }

            // If we got this far, something failed, redisplay form
            return View(model);
        }

Code for ApplicationViewPage class

public abstract class ApplicationViewPage : WebViewPage
    {
        protected override void InitializePage()
        {
            SetViewBagDefaultProperties();
            base.InitializePage();
        }

        private void SetViewBagDefaultProperties()
        {
            ViewBag.LayoutModel = new LayoutModel(Request.ServerVariables["SERVER_NAME"]);
        }

    }

The above code allow me to have a ViewBag.LayoutModel that hold an instance of my LayoutModel class in every page.

Here is a code for my LayoutModel class

public class LayoutModel
    {
        public string LayoutFile { get; set; }
        public string IpsTop { get; set; }
        public string IpsBottom { get; set; }
        public string ProfileTop { get; set; }
        public string ProfileBottom { get; set; }

        public LayoutModel(string hostname)
        {
            switch (hostname.ToLower())
            {
                default:

                    LayoutFile = "~/Views/Shared/_BnlLayout.cshtml";
                    IpsBottom = "~/Template/_BnlIpsBottom.cshtml";
                    IpsTop = "~/Template/_BnlTop.cshtml";
                    ProfileTop = "~/Template/_BnlProfileTop.cshtml";
                    break;

                case "something.com":
                    LayoutFile = "~/Views/Shared/_Layout.cshtml";
                    IpsBottom = "~/Template/_somethingBottom.cshtml";
                    IpsTop = "~/Template/_somethingTop.cshtml";
                    ProfileTop = "~/Template/_somethingProfileTop.cshtml";
                    break;
            }
        }
    }

Here is the code to the View

@{
    ViewBag.Title = "PageTitle";
    Layout = @ViewBag.LayoutModel.LayoutFile; 
}
@using (Html.BeginForm())
{
    @ViewBag.ErrorMessage
    
    html stuff here       
}

Refer to the following question for more detail. Make sure you modify your web.config as described there: How to set ViewBag properties for all Views without using a base class for Controllers?