ASP.NET _ViewStart.cshtml - Getting the Request

问题

I have an ASP.NET app. My app has a _ViewStart.cshtml file. That file looks like this:

@using MyCompany.MyApp;
@{
  Layout = "/Views/Shared/_Layout.cshtml";

  var p = HttpContext.Current.Request.QueryString["parameter"];
  ViewBag.QSParameter = p;
}

When I execute this code, I get the following error:

The name 'HttpContext' does not exist in the current context

I don't understand. Isn't _ViewStart.cshtml kind of the "shell" for the views? I'm trying to figure out how to globally read a query string parameter and set a value on the ViewBag for each request. I thought this would be the way to do it.

Thanks

回答1:

To retrieve it from _ViewStart.cshtml, you can use:

ViewBag.QSParameter = Context.Request.Query["parameter"];

Note: Use Query now (over QueryString) in ASP.NET 5

However, I might ellect to go a different route and take advantage of IResultFilter:

public class QSParameterFilter : IResultFilter
{
  public void OnResultExecuting(ResultExecutingContext context)
  {
    var QSParameter = context.HttpContext.Request.Query["parameter"];
    ((Controller)context.Controller).ViewBag.QSParameter = QSParameter;
  }
  public void OnResultExecuted(ResultExecutedContext context) { }
}

Then, register it within your Startup.cs:

services.AddMvc();
services.Configure<MvcOptions>(options => {
  options.Filters.Add(new QSParameterFilter());
});

回答2:

You should have access to Request in your _ViewStart file.

Try this:

@using MyCompany.MyApp;
@{
  Layout = "/Views/Shared/_Layout.cshtml";

  var p = Request.QueryString["parameter"];
  ViewBag.QSParameter = p;
}

EDIT: For ASP.NET 5

I don't have ASP.NET 5 on my machine but have looked at the source code for the framework. It looks like there is a Context property on RazorPage that returns an HttpContext. Alternatively, you can access the HttpContext through the ViewContext. See below:

@{
  Layout = "/Views/Shared/_Layout.cshtml";

  var p = Context.Request.Query["parameter"];
  // or this...
  // var p = ViewContext.HttpContext.Request.Query["parameter"];
  ViewBag.QSParameter = p;
}

来源：https://stackoverflow.com/questions/32127261/asp-net-viewstart-cshtml-getting-the-request

标签

razor

asp.net-core