MSBuild - how to copy files that may or may not exist?

问题

I have a situation where I need to copy a few specific files in a MSBuild script, but they may or may not exist. If they don't exist it's fine, I don't need them then. But the standard <copy> task throws an error if it cannot find each and every item in the list...

回答1:

Use the Exists condition on Copy task.

<CreateItem Include="*.xml">
  <Output ItemName="ItemsThatNeedToBeCopied" TaskParameter="Include"/>
</CreateItem>

<Copy SourceFiles="@(ItemsThatNeedToBeCopied)"
      DestinationFolder="$(OutputDir)"
      Condition="Exists('%(RootDir)%(Directory)%(Filename)%(Extension)')"/>

回答2:

The easiest would be to use the ContinueOnError flag http://msdn.microsoft.com/en-us/library/7z253716.aspx

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

    <ItemGroup>
        <MySourceFiles Include="a.cs;b.cs;c.cs"/>
    </ItemGroup>

    <Target Name="CopyFiles">
        <Copy
            SourceFiles="@(MySourceFiles)"
            DestinationFolder="c:\MyProject\Destination"
            ContinueOnError="true"
        />
    </Target>

</Project>

But if something else is wrong you will not notice it. So the condition exist from madgnome's answer would be better.

回答3:

It looks like you can mark MySourceFiles as SkipUnchangedFiles="true" and it won't copy the files if they already exist.

来源：https://stackoverflow.com/questions/511829/msbuild-how-to-copy-files-that-may-or-may-not-exist