How to change custom page label text on the fly in nsis?

I have written a custom page where i want to change the label text on the fly .I tried following code but some how I could not bale to change the text .

    Function Maintainance 
    nsDialogs::Create 1018
        Pop $Dialog
        ${If} $Dialog == error
            Abort
        ${EndIf}


        ${NSD_CreateLabel} 0 0 100% 12u "The $CurrentVersion complete installation folder is available at the below link"
        Pop $Label
    FindWindow $0 "#32770" "" $HWNDPARENT
     GetDlgItem $1 $0 1006


    SendMessage $1 ${WM_SETTEXT} 0 "STR:new value 111111"
    nsDialogs::Show
FunctionEnd

Any pointer on this will be a help.

Solution

The custom page is not visible until you call nsDialogs::Show. Any dynamic action has to happen after that with a timer or in response to a user action:

Page Custom MyPageCreate
Page InstFiles

!include nsDialogs.nsh

var mylabel

Function MyPageCreate
nsDialogs::Create 1018
Pop $0
${NSD_CreateLabel} 0 0 100% 12u "Hello"
Pop $mylabel
${NSD_CreateButton} 0 50% 50% 12u "Change"
Pop $0
${NSD_OnClick} $0 ChangeIt
nsDialogs::Show
FunctionEnd

Function ChangeIt
System::Call kernel32::GetTickCount()i.r0
SendMessage $mylabel ${WM_SETTEXT} 0 "STR:World! $0"
FunctionEnd