如何在ASP.NET MVC页面中声明全局变量

Question

I've began working with asp.net mvc very recently and I've ran into a problem. I've got an aspx page which renders a few ascx pages. What I'd like to do is declare a global var at the aspx page so it is visible to all its childs. I tried <% var i = 0; %> <% var i = 0; %> but it wasn't visible at the child pages.

What could I do?

Answer 1

variables from a aspx page are not shared with the partial views. The view is just a representation of a piece of data. You have to pass the data as a Model to each view you want to render, whether it's a plain View or a PartialView.

<% Html.RenderPartial("ViewName", Model, ViewDataDictionnary) %>

If you want to pass a variable to a partial view, I would strongly recommend you to add this parameter to the model of the partial view, rather that to pass it additionally via the ViewDataDictionnary.

Answer 2

You can add it to the ViewData and then pass the ViewData to the ascx with

<% Html.RenderPartial("ViewName", Model, ViewData) %>

see msdn on RenderPartial

So in your aspx page you'd do something like

<% ViewData["i"] = 0; %>

And in your userControl you'd just retrive it and use it as you want

<% int i = (int)ViewData["i"] %>

Another way would be to use RenderAction eand pass it as a parameter... so we'd need to know how you display your ascx.

see msdn on RenderAction