c# - do asp page variables not persist? -
i have following test asp page:
<html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> <asp:label id="label1" runat="server" text="label"></asp:label> <asp:button id="button1" runat="server" text="button" onclick="button1_click" /> </div> </form> </body> </html> with following code behind:
public partial class test : system.web.ui.page { int x = 0; protected void page_load(object sender, eventargs e) { label1.text = x.tostring(); } protected void button1_click(object sender, eventargs e) { x++; label1.text = x.tostring(); } } from non web programming mindset have thought int x have been sort of object field test page class , when x++ value of x persist through postbacks seems not case. how these feilds work in terms of persistance? find odd because when click button label1.text changed 1 first time click can't past 1 after that.
then once understand why happening easiest way make happen wanting? (value of x persists across postbacks)
this looks using viewstate looking for:
public partial class test : system.web.ui.page {
//static int x = 0; protected void page_load(object sender, eventargs e) { if (viewstate["x"] == null) { viewstate["x"] = 0; label1.text = viewstate["x"].tostring(); } //label1.text = x.tostring(); } protected void button1_click(object sender, eventargs e) { viewstate["x"] = convert.toint32(viewstate["x"].tostring()) + 1; label1.text = viewstate["x"].tostring(); //x++; //label1.text = x.tostring(); } }
x not persisted. upon each request, x initialised 0.
use, example, session state store value of x e.g. session["x"] = x;
as label text, asp.net store inside of viewstate, persists control values on each request. can use viewstate if want store value used on 1 page. use session if want value available on other pages in site.
viewstate["x"] = x;
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