How To Get a QueryString Value in Razor

A frequent pattern for me when dealing with articles or calendar events in Umbraco, is to initially render a selection (e.g. the latest 10 articles), and then provide some kind of filtering method to be able to access more (or a less) of these, subsequently.

I always use a QueryString parameter for this, e.g.:

https://example.com/articles/ will get me the initial list

https://example.com/articles/?tag=xslt will get me only the articles tagged with xslt

In “old” Umbraco (ASP.NET, I think?) this was accomplished using the Request.QueryString object - it was even “forwarded” to XSLT macros by way of umbraco.library.RequestQueryString, so really a no-brainer (meaning someone like me could figure it out 😀) to “just” make your view aware of some sort of config parameter.

When Umbraco switched from ASP.NET to .NET Core (or whatever it’s called these days) this got exponentially harder, at least for me, because of this thing called dependency injection (though I will admit that it’s fairly straight-forward to work with in a Razor view, as opposed to a helper class where somehow I’m still unable to do the correct incantations).

If I need to get the “tag” parameter from the QueryString - here’s how I do it currently:

// Inject the HttpContextAccessor
@inject Microsoft.AspNetCore.Http.IHttpContextAccessor HttpContextAccessor;
@{
	// Get a context
	var httpContext = HttpContextAccessor.HttpContext;

	// Grab the value(s) you need
	var tag = httpContext.Request.Query["tag"].ToString();
}

I can’t tell you how much I dislike that .ToString() there - but if you want to do practically anything else than just render the value, you have to cast it because the actual value is not a string… ¯\(ツ)/¯