我花了一段时间，但这是我自己解决的方法。这可能是caveman_dick 的第三个选项的变体。
1) 将新操作添加到 UISequence 以备份您当前的配置文件。您可以使用自定义操作和 ComponentSearch 的魔力来实际定位文件。
2) 稍后在 ExecuteSequence 中恢复文件。
<Binary Id="CustomActions.CA.dll" SourceFile="..\CustomActions\bin\$(var.Configuration)\CustomActions.CA.dll" />
<CustomAction Id="BackupConfigFile"
Return="check"
BinaryKey="CustomActions.CA.dll"
DllEntry="BackupFile" />
<CustomAction Id="RestoreConfigFile"
Return="check"
Execute="deferred"
Impersonate="no"
BinaryKey="CustomActions.CA.dll"
DllEntry="RestoreFile" />
<CustomAction Id="PropertyDelegator"
Property="RestoreConfigFile"
Value="MYTARGET=[MYTARGET];FILENAME_TO_BACKUP=[FILENAME_TO_BACKUP]" />
<Property Id="FILENAME_TO_BACKUP" Value="test.exe.config" />
<Property Id="PREVIOUS_PATH">
<ComponentSearch Id="evSearch" Guid="{010447A6-3330-41BB-8A7A-70D08ADB35E4}" />
</Property>
这是我写的快速 CustomAction.cs：
[CustomAction]
public static ActionResult BackupFile(Session session)
{
try
{
// check out if the previous installation has our file included
// and if it does,
// then make copy of it.
var previousInstallationPath = session["PREVIOUS_PATH"];
var fileToBackup = session["FILENAME_TO_BACKUP"];
if (!string.IsNullOrEmpty(previousInstallationPath) && !string.IsNullOrEmpty(fileToBackup))
{
var absolutePath = Path.Combine(previousInstallationPath, fileToBackup);
if (File.Exists(absolutePath))
{
var destinationPath = Path.Combine(Path.GetTempPath(),
string.Concat(fileToBackup, _MODIFIER));
File.Copy(absolutePath, destinationPath);
}
}
}
catch (Exception e)
{
session.Log("Couldn't backup previous file: {0}", e);
}
return ActionResult.Success;
}
[CustomAction]
public static ActionResult RestoreFile(Session session)
{
try
{
// check if our CustomAction made backup of file,
// and if it indeed exists in temp path, then
// we basically copy it back.
var currentInstallationPath = session.CustomActionData["MYTARGET"];
var fileToRestore = session.CustomActionData["FILENAME_TO_BACKUP"];
var fileOriginalContentPath = Path.Combine(Path.GetTempPath(),
string.Concat(fileToRestore, _MODIFIER));
if (File.Exists(fileOriginalContentPath))
{
var destinationFile = Path.Combine(currentInstallationPath, fileToRestore);
if (File.Exists(destinationFile))
File.Delete(destinationFile);
File.Move(fileOriginalContentPath, destinationFile);
}
}
catch (Exception e)
{
session.Log("Couldn't restore previous file: {0}", e);
}
return ActionResult.Success;
}
实际定义序列：
<InstallUISequence>
<Custom Action="BackupConfigFile" After="AppSearch"></Custom>
</InstallUISequence>
<InstallExecuteSequence>
<Custom Action="PropertyDelegator" Before="RestoreConfigFile" />
<Custom Action="RestoreConfigFile" After="InstallFiles"></Custom>
</InstallExecuteSequence>
尚未对其进行彻底测试，但目前似乎可以完成这项工作。警告：临时文件夹可能会改变？！
另外有一个是我从网上找的，但没有测试过。
<!-- Support Upgrading the Product -->
<Upgrade Id="{B0FB80ED-249E-4946-87A2-08A5BCA36E7E}">
<UpgradeVersion Minimum="$(var.Version)"
OnlyDetect="yes" Property="NEWERVERSIONDETECTED" />
<UpgradeVersion Minimum="0.0.0"
Maximum="$(var.Version)" IncludeMinimum="yes"
IncludeMaximum="no"
Property="OLDERVERSIONBEINGUPGRADED" />
</Upgrade>
<Property Id="OLDERVERSIONBEINGUPGRADED" Secure="yes" />
<!-- Action to save and Restore the Config-File on reinstall
-->
<!-- We're using CAQuietExec to prevent DOS-Boxes from
popping up -->
<CustomAction Id="SetQtCmdLineCopy" Property="QtExecCmdLine"
Value=""[SystemFolder]cmd.exe" /c copy
"[INSTALLDIR]MyApp.exe.config"
"[INSTALLDIR]config.bak"" />
<CustomAction Id="QtCmdCopy" BinaryKey="WixCA"
DllEntry="CAQuietExec" Execute="immediate" />
<CustomAction Id="SetQtCmdLineRestore"
Property="QtCmdRestore" Value=""[SystemFolder]cmd.exe" /c move
/Y "[INSTALLDIR]config.bak"
"[INSTALLDIR]MyApp.exe.config"" />
<CustomAction Id="QtCmdRestore" Execute="commit"
BinaryKey="WixCA" DllEntry="CAQuietExec" />
<!-- These actions will run only for a major upgrade -->
<InstallExecuteSequence>
<Custom Action="SetQtCmdLineCopy"
After="InstallInitialize"> NOT (OLDERVERSIONBEINGUPGRADED = "")</Custom>
<Custom Action="QtCmdCopy"
After="SetQtCmdLineCopy">NOT (OLDERVERSIONBEINGUPGRADED = "")</Custom>
<Custom Action="SetQtCmdLineRestore"
Before="InstallFinalize">NOT (OLDERVERSIONBEINGUPGRADED = "")</Custom>
<Custom Action="QtCmdRestore"
After="SetQtCmdLineRestore">NOT (OLDERVERSIONBEINGUPGRADED =
"")</Custom>
</InstallExecuteSequence>