问题:

Can anyone help me with the subject? I'm using Razor view engine and I need to pass some data to _Layout. How can I do it?

回答1:

As usual you start by creating a view model representing the data:

public class MyViewModel
{
    public string SomeData { get; set; }
}

then a controller which will fetch the data from somewhere:

public class MyDataController: Controller
{
    public ActionResult Index()
    {
        var model = new MyViewModel
        {
            SomeData = "some data"
        };
        return PartialView(model);
    }
}

then a corresponding view (~/Views/MyData/Index.cshtml) to represent the data:

@{
    Layout = null;
}
<h2>@Model.SomeData</h2>

and finally inside your _Layout.cshtml include this data somewhere:

@Html.Action("index", "mydata")

回答2:

You could use the ViewBag to pass data.

In your controller:

ViewBag.LayoutModel = myData;

Access in you layout:

@ViewBag.LayoutModel

It is a dynamic object, so you can use any property name you want.

回答3:

The ViewBag method is the easiest. However if you need advanced and typed features, you can also try taking that part to a partial view (the part that'll render the dependent section) with a common controller (if the value can be calculated on it's own and doesn't need input from other controllers), and call RenderPartial on it from _Layout.
If you'd like I can give you some more info about it...