Life cycle analysis of asp.net MVC preview (iii.)

Take a detailed look at the execution of the Invokeaction method:

protected internal bool Invokeaction (string actionname) {
return invokeaction (ActionName, New routevalued Ictionary ()); 　　　　　　
}
Protected internal virtual bool Invokeaction (string actionname, routevaluedictionary values) {
if (String.IsNullOrEmpty (ActionName)) {
throw new ArgumentException (Mvcresources.common_nullorempty, "actio Nname ");
}
//We have to loop through all the methods to make sure there isn ' t
/a conflict. 　　　　 　　If we stop the loop the "the" we find a match
//We might miss some error cases.
memberinfo[] Membinfos = GetType (). GetMember (ActionName, Membertypes.method,
Bindingflags.ignorecase | BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public);
MethodInfo foundmatch = null; 　　　　　　　 　
foreach (MemberInfo memberinfo in Membinfos) {
MethodInfo mi = (MethodInfo) MemberInfo;
1 Action methods must not have the non-action attribute in their inheritance chain, and
//2) Special methods-like constructors, property acces Sors, and event accessors cannot to action methods, and
//3) methods originally defined on Object (like Tostr ing) or Controller cannot be action methods.
if (!mi. IsDefined (typeof (Nonactionattribute), true) &&
!mi. Isspecialname &&
mi. Declaringtype.issubclassof (typeof (Controller))) {
if (foundmatch!= null) {
throw new inval Idoperationexception (
String.Format cultureinfo.currentuiculture, MVCRESOURCES.CONTROLLER_MORETHANONEAC tion, ActionName, GetType ())); 　　　　　　　　
}
Foundmatch = mi;
　　　　　　　　
}
if (Foundmatch!= null) {
Invokeactionmethod (Foundmatch, values);
return true; 　　　　
}
return false;
}It obtains all Action method information of the same name by reflection, and secondly, it filters out all methods with Nonactionattribute and isspecialname tags; third, it throws an exception when a valid Action of the same name is overloaded (prompt controller_mo Rethanoneaction), continue to invoke Invokeactionmethod:

[SuppressMessage ("Microsoft.Design", "CA1011: Considerpassingbasetypesasparameters ",


justification = "We use MethodInfo since it represents only methods and not constructors." +


"This method is only makes sense to use with methods.")]


protected internal virtual void Invokeactionmethod (MethodInfo MethodInfo, routevaluedictionary values) {


if (methodInfo = = null) {


throw new ArgumentNullException ("MethodInfo");


　　 }


if (values = = null) {


values = new RouteValueDictionary ();


　　 }


if (methodinfo.containsgenericparameters) {


throw new InvalidOperationException (String.Format (CultureInfo.CurrentUICulture, Mvcresources.controller_ Actioncannotbegeneric, Methodinfo.name));


　　 }


parameterinfo[] methodparameters = Methodinfo.getparameters ();


object[] parametervalues = null;


if (methodparameters.length > 0) {


parametervalues = new Object[methodparameters.length];


for (int i = 0; i < methodparameters.length; i++) {


parameterinfo pi = methodparameters[i];


if (pi. Isout | | Pi. PARAMETERTYPE.ISBYREF) {


throw new InvalidOperationException (String.Format cultureinfo.currentuiculture, mvcresources.controller_re ferenceparametersnotsupported, Pi. Name, Methodinfo.name));


　　　　　　 }


bool valuerequired = true;


if (pi. Parametertype.isclass) {


Classes (ref types) don ' t require values since we can pass in null


valuerequired = false;


　　　　　　 }


else {


if (pi. Parametertype.isgenerictype &&! Pi. parametertype.isgenerictypedefinition) &&


(pi. Parametertype.getgenerictypedefinition () = = typeof (Nullable<>))) {


//Nullable types don ' t require values since we can pass in null


valuerequired = false;


　　　　　　　　 }


　　　　　　 }


//Try to get a value for the parameter. We Use this order of precedence:


//1. explicitly-provided extra parameters in the call to Invokeaction ()


//2. Values from the Routedata (could to the typed-in URL or from the route ' s default values)


3. Request values (query string, form post data, cookie)


object parametervalue = null;


if (!values. TryGetValue (Methodparameters[i]. Name, out ParameterValue)) {


if (routedata = NULL | |! RouteData.Values.TryGetValue (Methodparameters[i]. Name, out ParameterValue)) {


if (Request!= null) {


parametervalue = request[methodparameters[i]. Name];


　　　　　　　 　　　 }


　　　　　　　　 }


　　　　　　 }


if (ParameterValue = = null && valuerequired) {


throw new InvalidOperationException (String.Format cultureinfo.currentuiculture, mvcresources.controller_m Issingparameter, Pi. Name, Methodinfo.name));


　　　　　　 }


try {


Parametervalues[i] = Convertparametertype (ParameterValue, methodparameters[i). ParameterType, Methodparameters [i]. Name, Methodinfo.name);


　　　　　　 }


catch (Exception ex) {


//Parameter value conversion errors are acceptable unless the value is required


if (valuerequired) {


throw new InvalidOperationException (String.Format cultureinfo.currentuiculture, mvcresources.controller_m Issingparameter, Pi. Name, Methodinfo.name), ex);


　　　　　　　　 }


　　　　　　 }


　　　　 }


　　 }


invokeactionmethodfilters (MethodInfo, () => Methodinfo.invoke (this, parametervalues));


}