verify the existence of a folder using the msbuild extension pack? - msbuild

Question

How can I dependably verify the existence of a folder using an msbuild extension pack task?
How could i do it without throwing an error and stopping the build?

Answer 1

Could you use the Exists condition on a target?
This will execute the OnlyIfExists target only if there is a directory or file called Testing in the same directory as the msbuild file.
<ItemGroup>
<TestPath Include="Testing" />
</ItemGroup>
<Target Name="OnlyIfExists" Condition="Exists(#(TestPath))">
<Message Text="This ran!" Importance="high" />
</Target>

Answer 2

There is no need to use the extension pack, MSBuild can handle this just fine. You need to consider whether this is a folder that might be created or deleted as part of the build. If it is, then you want to be sure to use a dynamic item group declared within a target (in the case of checking more than one folder) or you can use a path if just checking one. This example shows both:
<Target Name="MyTarget">
<!-- single folder with property -->
<PropertyGroup>
<_CheckOne>./Folder1</_CheckOne>
<_CheckOneExistsOrNot
Condition="Exists('$(_CheckOne)')">exists</_CheckOneExistsOrNot>
<_CheckOneExistsOrNot
Condition="!Exists('$(_CheckOne)')">doesn't exist</_CheckOneExistsOrNot>
</PropertyGroup>
<Message
Text="The folder $(_CheckOne) $(_CheckOneExistsOrNot)"
/>
<!-- multiple folders with items -->
<ItemGroup>
<_CheckMultiple Include="./Folder2" />
<_CheckMultiple Include="./Folder3" />
</ItemGroup>
<Message
Condition="Exists('%(_CheckMultiple.Identity)')"
Text="The folder %(_CheckMultiple.Identity) exists"
/>
<Message
Condition="!Exists('%(_CheckMultiple.Identity)')"
Text="The folder %(_CheckMultiple.Identity) does not exist"
/>
</Target>