how to use view state in code behind files in C#

ajeshss · June 13th, 2006, 11:50 PM

i am using a html control dropdownlist. i am not writing it inside form. so i put a hidden
value inside the form.on change of the dropdownlist,a funciton is called themechange(). and the value
which i selected will goto code behind files. when i select value form dropdown,the theme of the
site will change.

function themechange()
    {
        var s = document.getElementById("refer");
        //alert(s);
        document.getElementById("theme").value = s.options[s.options.selectedIndex].value;
        //alert(document.getElementById("theme").value);

        if(document.getElementById("theme").value != null)
        {
            document.forms(0).elements['themeresult'].value = document.getElementById("theme").value;
            //alert(document.forms(0).elements['themeresult'].value);
        }
        document.forms(0).submit();
        parent.window.location.reload();
    }

</script>

<body onload="displaymsg();" onunload="if (newwin && !newwin.closed) newwin.close();if (timerWindow && !timerWindow.closed) timerWindow.close(); deleteSession();">
        <DIV align=center>
            <table border=0 cellpadding=0 cellspacing=0 width=100% height=100% class=footertable ID="Table2">
                   <tr>
                     <td colspan="5" bgcolor="#5A82AD" valign=middle>
                        <p align=center><small><small>Copyright
                            © Wipro Ltd. 2005. Best Viewed in 1024 x 800 I.E. 6.0 with SP1 & Above                            </small></small>

                             <SELECT id="themes" onchange="themechange();" name="refer">
                                        <OPTION VALUE='' SELECTED>--- Select ---</OPTION>
                                        <OPTION VALUE="theme1" id="theme1">Theme 1</option>
                                        <OPTION VALUE="theme2" id="theme2">Theme 2</option>
                                        <OPTION VALUE="theme3" id="theme3">Theme 3</option>
                                    </SELECT>
                    </td>
                </tr>
            </table>
        </div>
        <div id='alert' style='display:none'></div>
        <form name="frm" ID="Form1" runat="server">
            <input type="hidden" name="timespent">
            <input type="hidden" name="sessionid" value=sessionid>
            <input type="hidden" name="MaxIncId" >
            <input type="hidden" name="theme" >
            <input type="hidden" name="themeresult">
        </form>

codebehind file

if(Request["themeresult"] != null)
    {
    string result ;
    result= Request["themeresult"];
    switch(result)
        {
        case ("theme1"):
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheet.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme2.css");
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme1.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheet.css");
        break;

        case ("theme2"):
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheet.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme4.css");
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme3.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheet.css");
        break;

        case ("theme3"):
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheet.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme6.css");
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme5.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheet.css");
        System.IO.File.Move("F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme6.css", "F:\\DEVELOPMENT 2.0\\e-Helpline\\_StyleLibrary\\stylesheettheme5.css");
        Page.RegisterStartupScript("test",@"<script>parent .window.location.reload();</script>");
        break;
        }
    }

what my problem is, whenever i select theme, its changing but i need to toggle it again to bring back to original theme.
i have use viewstate to resolve the problem.
i have stylesheet.css where it is called all over the place. i have theme1.css, i rename the stylesheet.css to a temporary
stylesheet1.css and theme1.css to stylesheet.css.
now using viewstate, i need to bring back to the original theme.since if i select theme2 or theme3. it should work properly.

i just want to know , how viewstate is used in code behind files?

ajesh

ajeshss · June 14th, 2006, 02:28 AM

did anyone know how to use viewstate in switch case statement?

ajesh

ajeshss · June 14th, 2006, 06:03 AM

i will make my question little more clearer.
i have a drop down box having theme1,theme2 and theme3 as values.
the default stylesheet for the site is stylesheet.css
when i select theme1. the entire site get changed to theme1.

how i did this is
system.file.io.move(\\stylesheet.css, \\ stylesheet1.css)
system.file.io.move(\\stylesheettheme1.css, \\stylesheet.css)
now stylesheet.css contain stylesheettheme1.css

now i am problem is if i select theme2. again i will use move method to replace file,
system.file.io.move(\\stylesheet.css, \\ stylesheet2.css)
system.file.io.move(\\stylesheettheme2.css, \\stylesheet.css)
but here the stylesheet contain stylesheettheme1.css which i changed when i click theme1.
now when i select theme1, theme1 should apply my site and by using the viewstate property i want to change back to my default site.
how can i do that using viewstate.
can anyone please help me in this matter
thanx
ajesh

ajeshss · June 14th, 2006, 07:39 AM

i have a drop down list containing values theme1, theme2 , theme3
corresponding to theme1 is stylesheet1, theme2 is stylesheet2 etc

when i select theme1 the entire site get changed.then the viewstate value is say 1, now when i select theme2 or theme3 etc,
my viewstate value will be changed accordingly. now i have to comapre old viewstate with new viewstate.

the default stylesheet will change according to the selection in the dropdown. if i select theme1, default stylesheet will be changed to theme1. when i select theme2, default stylesheet should become theme2 but i am having theme1 as a default. so when i select theme2,it is overwriting theme1.it should not happen. in that case i need to use viewstate.

did anyone know how to solve my problem, its very urgent.
plz help me

thanx

rumbafum · June 20th, 2006, 06:00 AM

You use ViewState same way you use Session

ViewState["somevalueToStore"] = textBox1.Text;
....
string storedValue = (string)ViewState["someValueToStore"];