Introducere in ASP.NET Controale Web Pagina in ... - Profs.info.uaic.ro
Introducere in ASP.NET Controale Web Pagina in ... - Profs.info.uaic.ro
Introducere in ASP.NET Controale Web Pagina in ... - Profs.info.uaic.ro
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<st<strong>ro</strong>ng>ASP</st<strong>ro</strong>ng>.<st<strong>ro</strong>ng>NET</st<strong>ro</strong>ng> 03.03.2014 8/30<br />
Modelul Event <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>ASP</st<strong>ro</strong>ng>.<st<strong>ro</strong>ng>NET</st<strong>ro</strong>ng><br />
Acest model descrie modul de tratare al evenimentelor diverselor cont<strong>ro</strong>ale cont<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>ute <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng><br />
. Adaugam cont<strong>ro</strong>ale la formularul web si apoi decidem ce evenimente sa tratam.<br />
Observatie<br />
Modelul este asemanator cu cel dat de W<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>dows Forms, dar lucreaza diferit. Numarul<br />
evenimentelor implementate de cont<strong>ro</strong>ale este redus <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> comparatie cu W<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>dows Forms.<br />
1. Pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a ruleaza pentru prima data.<br />
<st<strong>ro</strong>ng>ASP</st<strong>ro</strong>ng>.<st<strong>ro</strong>ng>NET</st<strong>ro</strong>ng> creaza pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a si cont<strong>ro</strong>alele d<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a, executa codul de <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>itializare si apoi<br />
pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a este returnata clientului. Obiectul Page si cont<strong>ro</strong>alele ce le cont<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>e sunt elim<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>ate<br />
d<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> memorie (sunt distruse).<br />
2. Clientul executa actiuni asupra pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>ii (completare cont<strong>ro</strong>ale d<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a, etc.) ce au<br />
ca efect un postback. Pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a este trimisa cu toate datele d<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> form catre server.<br />
3. <st<strong>ro</strong>ng>ASP</st<strong>ro</strong>ng>.<st<strong>ro</strong>ng>NET</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>tercepteaza pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a returnata si recreaza obiectele d<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a la starea pe<br />
care au avut-o ultima data.<br />
4. <st<strong>ro</strong>ng>ASP</st<strong>ro</strong>ng>.<st<strong>ro</strong>ng>NET</st<strong>ro</strong>ng> verifica c<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>e a generat postback si apeleaza metoda corespunzatoare acelui<br />
eveniment (de ex. clic pe un buton). In acest moment se executa cod pe server (actualizare<br />
baze de date, etc.) si apoi se modifica obiectele cont<strong>ro</strong>alelor pentru a reflecta noua<br />
<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>formatie.<br />
5. Pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a este transformata <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> HTML, trimisa clientului si apoi distrusa d<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng> server.<br />
Daca pe aceeasi pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>a apare un nou postback se reia ciclul de la psul 2.<br />
Postback automat<br />
In <st<strong>ro</strong>ng>ASP</st<strong>ro</strong>ng>.<st<strong>ro</strong>ng>NET</st<strong>ro</strong>ng> actiunile le genereaza clientul si serverul p<strong>ro</strong>ceseaza codul<br />
corespunzator. Anumite evenimente cum ar fi miscarea mouse-ului nu sunt tratate implicit.<br />
Nu mai exista acea bucla de mesaje ce caracterizeaza o aplicatie W<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>dow.<br />
Evenimentele sunt regenerate pe partea de server numai dupa ce s-a facut un postback al<br />
pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>ii.<br />
Exista cont<strong>ro</strong>ale ce au posibilitatea de a face postback automat, acest lucru <st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>semnand ca la<br />
generarea unui eveniment al cont<strong>ro</strong>lului, cont<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>utul pag<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>ii este trims catre server.<br />
<st<strong>ro</strong>ng>Cont<strong>ro</strong>ale</st<strong>ro</strong>ng>le trebuie sa aiba setata p<strong>ro</strong>prietatea<br />
AutoPostBack = true<br />
Ioan Asim<st<strong>ro</strong>ng>in</st<strong>ro</strong>ng>oaei