Using ActionFilter
Action filters that are actually attributes can be registered as an attribute of an Action or a Controller, as illustrated in the following code snippet:
[HttpPost]
[ValidateModel] // ActionFilter as attribute
public ActionResult<Person> Post([FromBody] Person model)
{
// save the person
return model; //just to test the action
}
Here, we use ValidateModel attribute that checks the ModelState and returns BadRequestObjectResult in case the ModelState is invalid; we don't need to check the ModelState in the actual Action.
To register action filters globally, you need to extend the MVC registration in the ConfigureServices method of the Startup.cs file, as follows:
builder.Services.AddControllersWithViews()
.AddMvcOptions(options =>
{
options.Filters.Add(new SampleActionFilter());
...