NSIS Resetting text and droplists upon button press - nsis

Question

Hope you guys can help me out again. I have created a custom page, and in that page are sever text fieldsa and 2 droplists. I also have a clear button that if pressed it clears all the fields on the screen.
Note: I used the code from TestNotify.nsu in examples
The issue I have is one, when pressing clear the values are written to the ini file so upon reloading the program the last Fields used populate (Even if I press clear, I have to press it twice clear the ini file)
Second is how do I reset the droplist to the default I selected when pressing reset.
So the only section I am working on now is the clearbtn, so how can i reset the droplists to a specific value, and clear data from ini when pressing clear only once.
###Add Auto Start option
SetCompressor lzma
XPStyle on
!define FolderImages "Included\Images"
!define ImageIcon "Icon.ico"
!define ImageHDR "HDR.bmp"
!define PRODUCT_NAME "Test"
!define PRODUCT_VERSION "1.0"
!define MUI_ICON ".\${FolderImages}\${ImageIcon}"
Icon ".\${FolderImages}\${ImageIcon}"
!include WinVer.nsh
!include LogicLib.nsh
!include x64.nsh
!include FileFunc.nsh
!include MUI.nsh
!include WinMessages.nsh
!include InstallOptions.nsh
!include Sections.nsh
!include nsDialogs.nsh
!define MUI_HEADERIMAGE
!define MUI_HEADERIMAGE_BITMAP ".\${FolderImages}\${ImageHDR}"
Page custom SetCustom ValidateCustom
!insertmacro MUI_LANGUAGE "English"
Function SetCustom
!insertmacro MUI_HEADER_TEXT "Licence Key Generator" "Create or Read Licence Keys"
#Hides the close button
GetDlgItem $R0 $HWNDPARENT 1
ShowWindow $R0 ${SW_HIDE}
InstallOptions::initDialog ".\UserProfiles.ini"
; In this mode InstallOptions returns the window handle so we can use it
Pop $0
; Now show the dialog and wait for it to finish
InstallOptions::show
; Finally fetch the InstallOptions status value (we don't care what it is though)
Pop $0
FunctionEnd
Function ValidateCustom
# At this point the user has either pressed cancel or one of our custom buttons
# We find out which by reading from the INI file
ReadINIStr $0 ".\UserProfiles.ini" "Settings" "State"
StrCmp $0 0 cancelbtn
StrCmp $0 19 createbtn
StrCmp $0 20 readbtn
StrCmp $0 21 comparebtn
StrCmp $0 22 clearbtn
Abort # Return to the page
createbtn:
Abort # Return to the page
readbtn:
Abort # Return to the page
comparebtn:
Abort # Return to the page
clearbtn:
#Text Field
ReadINIStr $1 ".\UserProfiles.ini" "Field 6" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
#Text Field
ReadINIStr $1 ".\UserProfiles.ini" "Field 8" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
#Text Field
ReadINIStr $1 ".\UserProfiles.ini" "Field 10" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
#Drop List ------------------------------------------------------------<<<<
ReadINIStr $1 ".\UserProfiles.ini" "Field 12" "HWND"
SendMessage $1 ${WM_SETTETX} 0 "STR:"
#Text Field
ReadINIStr $1 ".\UserProfiles.ini" "Field 14" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
#Drop List ------------------------------------------------------------<<<<
ReadINIStr $1 ".\UserProfiles.ini" "Field 16" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
#Text Field
ReadINIStr $1 ".\UserProfiles.ini" "Field 18" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
Abort # Return to the page
cancelbtn:
FunctionEnd
Section Dummy
SectionEnd

Answer 1

You can clear a droplist by sending the CB_RESETCONTENT message:
Var MyDir
Function .onInit
; Create example .ini
InitPluginsDir
StrCpy $MyDir $Temp ; Use something else in a real application, or use $PluginsDir.
WriteIniStr "$MyDir\UserProfiles.ini" "Settings" NumFields 4
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Type Button
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Left 0
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Right 50
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Top 0
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Bottom 14
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Text "&Clear"
WriteIniStr "$MyDir\UserProfiles.ini" "Field 1" Flags NOTIFY
WriteIniStr "$MyDir\UserProfiles.ini" "Field 2" Type Text
WriteIniStr "$MyDir\UserProfiles.ini" "Field 2" Left 0
WriteIniStr "$MyDir\UserProfiles.ini" "Field 2" Right 100
WriteIniStr "$MyDir\UserProfiles.ini" "Field 2" Top 15
WriteIniStr "$MyDir\UserProfiles.ini" "Field 2" Bottom 30
WriteIniStr "$MyDir\UserProfiles.ini" "Field 3" Type Droplist
WriteIniStr "$MyDir\UserProfiles.ini" "Field 3" Left 0
WriteIniStr "$MyDir\UserProfiles.ini" "Field 3" Right 100
WriteIniStr "$MyDir\UserProfiles.ini" "Field 3" Top 35
WriteIniStr "$MyDir\UserProfiles.ini" "Field 3" Bottom 99
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Type Button
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Left 55
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Right 105
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Top 0
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Bottom 14
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Text "&Add"
WriteIniStr "$MyDir\UserProfiles.ini" "Field 4" Flags NOTIFY
FunctionEnd
Function SetCustom
InstallOptions::initDialog "$MyDir\UserProfiles.ini"
; In this mode InstallOptions returns the window handle so we can use it
Pop $0
; Now show the dialog and wait for it to finish
InstallOptions::show
; Finally fetch the InstallOptions status value (we don't care what it is though)
Pop $0
FunctionEnd
Function ValidateCustom
# At this point the user has either pressed cancel or one of our custom buttons
# We find out which by reading from the INI file
ReadINIStr $0 "$MyDir\UserProfiles.ini" "Settings" "State"
StrCmp $0 1 clearbtn
StrCmp $0 4 addbtn
Abort # Return to the page
clearbtn:
#Text Field
ReadINIStr $1 "$MyDir\UserProfiles.ini" "Field 2" "HWND"
SendMessage $1 ${WM_SETTEXT} 0 "STR:"
#Droplist Field
ReadINIStr $2 "$MyDir\UserProfiles.ini" "Field 3" "HWND"
SendMessage $2 ${CB_RESETCONTENT} 0 0
DeleteIniStr "$MyDir\UserProfiles.ini" "Field 3" "ListItems"
DeleteIniStr "$MyDir\UserProfiles.ini" "Field 3" "State"
Abort # Return to the page
addbtn:
ReadINIStr $1 "$MyDir\UserProfiles.ini" "Field 2" "State"
ReadINIStr $2 "$MyDir\UserProfiles.ini" "Field 3" "HWND"
SendMessage $2 ${CB_ADDSTRING} 0 "STR:$1"
SendMessage $2 ${CB_SELECTSTRING} 0 "STR:$1"
Abort # Return to the page
FunctionEnd
You should not use relative .INI paths, that is just asking for trouble, use full paths!