如何在用户取消选择特定Feature时执行自定义操作？

要求在用户取消选择MyFeature时执行自定义Custom Action，无论当前操作是Repair、Upgrade还是Uninstall；但Upgrade过程中如果Feature被重新安装，则不执行该操作。

之前的尝试及问题 #

我曾尝试定义_UNINSTALLONLY属性来限制仅在卸载时执行：

<SetProperty Id="_UNINSTALLONLY" After="FindRelatedProducts" Value="1">
       <![CDATA[Installed AND NOT UPGRADINGPRODUCTCODE]]></SetProperty>

并在InstallExecuteSequence中添加延迟执行的CustomAction：

<Custom Action="HandleMyFeatureMyCustomActionOnUnselect" Before="InstallFinalize">
  <![CDATA[_UNINSTALLONLY AND (!MyFeature >= 2) AND (&MyFeature <= 2) ]]></Custom>

该方案在多数场景有效，但Upgrade过程中用户取消选择Feature时，操作不会被触发。

还尝试过其他条件，均存在问题：

• (!MyFeature >= 2) AND (&MyFeature <= 2)：Upgrade时，即使用户未更改选择也会触发操作
• _UNINSTALLONLY AND (&MyFeature <= 2)：Upgrade时取消选择其他Feature2也会触发操作

已实现功能及代码上下文 #

目前已实现升级时可靠移除旧版本、根据当前状态预选Feature的需求，相关代码如下：

CustomAction定义 #

<CustomAction Id="HandleMyFeatureMyCustomActionOnUnselect" BinaryKey="FeatureCustomActions"
    DllEntry="HandleMyFeatureMyCustomActionOnUnselect" Impersonate="no"  Execute="deferred"  
    Return="check" />

<CustomAction Id="SetHandleMyFeatureMyCustomActionOnUnselectPropertyValues" Property="HandleMyFeatureMyCustomActionOnUnselect" 
    Value="INSTALLFOLDER=[INSTALLFOLDER]" />    

<Property Id='INSTALLFEATURE'>
        <RegistrySearch Id='InstallFEATURE' Root='HKLM'
                        Key='SOFTWARE\Somewhere\AnotherKey'
                        Name='FEATUREINSTALLED' Type='raw' />
</Property>

InstallExecuteSequence #

<InstallExecuteSequence>
   <Custom Action="SetREINSTALL" Before="CostInitialize">
            Installed AND REMOVE ~= "" AND NOT REINSTALL
   </Custom>
   <RemoveExistingProducts After="InstallInitialize"/>
   ...
   <Custom Action="SetHandleMyFeatureMyCustomActionOnUnselectPropertyValues" Before="HandleMyFeatureMyCustomActionOnUnselect" ><![CDATA[_UNINSTALLONLY AND (!MyFeature >= 2) AND (&MyFeature <= 2) ]]></Custom>
   <Custom Action="HandleMyFeatureMyCustomActionOnUnselect" Before="InstallFinalize"><![CDATA[_UNINSTALLONLY AND (!MyFeature >= 2) AND (&MyFeature <= 2) ]]></Custom>
   ...
</InstallExecuteSequence>

Features定义 #

<Feature Id="MyFeature" Title="My Feature" ConfigurableDirectory="INSTALLFOLDER"  Display="expand" Level="1">
    <Condition Level="2">INSTALLFEATURE=0</Condition> 
    <ComponentGroupRef Id="FEATURE"/>
</Feature>
<Feature Id="MyFeature2" Title="My Feature2" ConfigurableDirectory="INSTALLFOLDER"  Display="expand" Level="1">
    <Condition Level="2">INSTALLFEATURE2=0</Condition> 
    <ComponentGroupRef Id="FEATURE2"/>
</Feature>

解决方案 #

要实现仅当用户将MyFeature从已选择改为未选择时执行自定义操作，需调整CustomAction的执行条件，覆盖所有目标场景并排除误触发情况：

调整CustomAction执行条件 #

替换原有的CustomAction触发条件，使用以下组合逻辑：

<Custom Action="SetHandleMyFeatureMyCustomActionOnUnselectPropertyValues" Before="HandleMyFeatureMyCustomActionOnUnselect" >
  <![CDATA[(!MyFeature >= 3) AND (&MyFeature <= 2) AND NOT REINSTALL~="MyFeature"]]>
</Custom>
<Custom Action="HandleMyFeatureMyCustomActionOnUnselect" Before="InstallFinalize">
  <![CDATA[(!MyFeature >= 3) AND (&MyFeature <= 2) AND NOT REINSTALL~="MyFeature"]]>
</Custom>

逻辑说明 #

• !MyFeature >=3：表示MyFeature在操作前处于已安装状态（Windows Installer中，Feature已安装对应的状态值为3）
• &MyFeature <=2：表示MyFeature的目标状态为未安装
• NOT REINSTALL~="MyFeature"：排除Upgrade或Repair过程中重新安装该Feature的场景，避免误触发

内容的提问来源于stack exchange，提问作者gReX