ASP. NET Web API data validation

The first way is to validate each action individually.

 //POST api/values         Publichttpresponsemessage Post ([Frombody]userinfo UserInfo) {if(string. Isnullorwhitespace (Userinfo.gender)) {Modelstate.addmodelerror ("Gender","gender cannot be empty"); }            if(modelstate.isvalid) {//Do something with the product (not shown).                return Newhttpresponsemessage (Httpstatuscode.ok); }            Else            {                returnrequest.createerrorresponse (Httpstatuscode.badrequest, modelstate); }        } Public classUserInfo { Public intId {Get;Set; }        [Required] [Stringlength ( -, errormessage ="The name's too long or too short.", Minimumlength =4)]         Public stringName {Get;Set; } [RegularExpression (@"([2-5]\d)", errormessage ="age is between 20-50")]         Public intAge {Get;Set; }  Public stringGender {Get;Set; } }

The second is to do global validation:

 Public class Validationattribute:actionfilterattribute    {        publicoverridevoid  onactionexecuting (Httpactioncontext actioncontext)        {            if (!  ActionContext.ModelState.IsValid)            {                = ActionContext.Request.CreateErrorResponse (                    Httpstatuscode.badrequest,                    actioncontext.modelstate);}}}    WebApiConfig.cs   CONFIG. Filters.add (new Validationattribute ());

ASP. NET Web API data validation