NSIS - Disable “Uninstall” button if no component is selected

Question

I have a NSIS script with two components to uninstall. If the user unchecks both components in the "Choose components" page, the Uninstall button is still active, and the uninstall process can continue without actually uninstalling anything. Is there any easy way to disable the "Uninstall" button if no component is selected? The code for selecting the uninstaller section is the following:

# Macro for selecting uninstaller sections
!macro SELECT_UNSECTION SECTION_NAME UNSECTION_ID
    Push $R0
    ReadRegStr $R0 HKLM "${REGKEY}\Components" "${SECTION_NAME}"
    StrCmp $R0 1 0 next${UNSECTION_ID}
    !insertmacro SelectSection "${UNSECTION_ID}"
    GoTo done${UNSECTION_ID}
next${UNSECTION_ID}:
    !insertmacro UnselectSection "${UNSECTION_ID}"
done${UNSECTION_ID}:
    Pop $R0
!macroend

Thanks in advance!

Answer 1

UninstPage Components un.InitComponents
UninstPage InstFiles

Section "un.Foo" SID_FOO
SectionEnd
Section /o "un.Bar" SID_BAR
SectionEnd

!include LogicLib.nsh

Function un.InitComponents
;!insertmacro SELECT_UNSECTION SECTION_NAME ...
Call un.onSelChange ; Make sure the initial button state is correct
FunctionEnd

Function un.onSelChange
GetDlgItem $1 $hwndParent 1
${If} ${SectionIsSelected} ${SID_FOO}
${OrIf} ${SectionIsSelected} ${SID_BAR}
    EnableWindow $1 1
${Else}
    EnableWindow $1 0
${EndIf}
FunctionEnd