How to get argument in action filter when the controller action has no corresponding argument?

Question

I am working on an ASP.NET Core 6 based web application. To avoid writing a lot of redundant code in my controllers, I implemented a class BaseController which all of my controllers inherit from. In that class, I overrided the OnActionExecutionAsync method to run the code which would otherwise be redundant in every controller. In this code, I need to access two arguments which I would otherwise have to pass to each controller action via its arguments like this: public async Task<ActionResult> ExampleAction([FromQuery(Name = "argument1")] Guid? argument1, [FromQuery(Name = "argument2")] Guid? argument2)

As long as I keep those arguments in every action, I can easily access them in the OnActionExecutionAsync method. However, I do not want to do it like this because it would require me to add the arguments to every single controller action while I do not even need them there. Now I have the problem that when I remove the arguments from the controller action, I can no longer access them via context.ActionArguments in the OnActionExecutionAsync method.

Is there any way how I can still access the arguments in this situation? I already found this question on SO which is very similar but the suggested solution to use actionContext.ControllerContext.RouteData.Values["tenant"] does not work in my case. There simply is no ControllerContext in ASP.NET Core 6 and context.RouteData.Values does not seem to contain the arguments I am looking for.

Answer 1

You can access the query-string values using HttpContext.Request.Query . Here's an example:

var tenantValues = context.HttpContext.Request.Query["tenant"];

The type of tenantValues here is StringValues , which represents one or more values. If you know there's only going to be one value provided, you can treat it as a collection and use [0] or First() , for example, or just case it as string .

Answer 2

You can use HttpContext property of ActionContext (which is ancestor of ActionExecutingContext ) to access request query string values:

public override Task OnActionExecutionAsync(ActionExecutingContext actionContext, ActionExecutionDelegate next)
{
    StringValues values = actionContext.HttpContext.Request.Query["tenant"];
}