ASP. NET WEB API model validation and exception handling

The model validation of the ASP. Net. NET MVC, like ASP, uses System.ComponentModel.DataAnnotations.

Specifically, for example, there are:
[Required (errormessage= "")]
[Range (0, 999)]
[Bind (Exclude= "")]
[DisplayName ("")]
[Stringlength (1024)]
...

The validation extension can be seen here: http://dataannotationsextensions.org/

How is the model validated in the controller?

Usually through the modelstate.isvalid.

 Public httpresponsemessage Post (product product) {    if(modelstate.isvalid) {        //         returnnew  httpresponsemessage (Httpstatuscode.ok);    }     Else     {        return  request.createerrorresponse (httpstatuscode.badrequest, Modelstate );    }}

You can also customize the attribute Actionfilterattibute attribute of a model validation in a "tangent-oriented" manner.

 Public class validatemodelattribute:actionfilterattibute{    publicoverride void  OnActionExecuting (Httpactioncontext actioncontext)    {        iffalse)        {             = actionContext.Request.CreateErrorResponse (httpstatuscode.badrequest, Actioncontext.modelstate );        }    }}

You then need to register the custom filter feature with the default filter set.

 Public Static class webapiconfig{    publicstaticvoid  Register (httpconfiguraiotn config)    {        config. Filters.add (new  Validatemodelattribute ());}    }

If the filter is not registered globally, we can also hit the filter feature to the controller or controller method.

[Validatemodel]  Public httpresponsemessage Post (product product) {}

ASP. NET WEB API model validation and exception handling