How to split string by multiple characters in MSBuild 4?

MSBuild 4.0 property functions cannot handle arrays (well basically), however when you do a

Split(`,`, `-`)

You are invoking the String.Split(params string[]) overload, which requires an array (even in C# the params keyword will create an array behind the scene and do something like Split(new string[] { ',', '-' }) internally).

What you could do is the following:

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"
 ToolsVersion="4.0">

    <PropertyGroup>
        <MasterVersion>1.1-SNAPSHOT</MasterVersion>
    </PropertyGroup>

    <ItemGroup>
        <SplitVersion Include="$(MasterVersion.Replace(`-`, `.`).Split(`.`))" />
    </ItemGroup>

    <Target Name="Test">
        <Message Importance="high" Text="@(SplitVersion)"/>
    </Target>
</Project>

Or you could first create the (string) array to be passed to Split:

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
    <PropertyGroup>
        <MasterVersion>1.1-SNAPSHOT</MasterVersion>
        <Delimiters>.;-</Delimiters>
        <DelimitersArray>$(Delimiters.Split(`;`))</DelimitersArray>
    </PropertyGroup>
    <ItemGroup>
        <SplitVersion Include="$(MasterVersion.Split($(DelimitersArray)))" />
    </ItemGroup>
    <Target Name="Test">
        <Message Importance="high" Text="@(SplitVersion)"/>
    </Target>
</Project>

Which is not really better in this case ;-)

Oh, and you might want to check out this MSDN blog entry for more useful information.

Update for a comment:

• The "content" of SplitVersion is technically an "array of ITaskItem", yes. You would deal with it however you would deal with Items (of ItemGroups); including things like "batching", etc.

• You cannot really "access things by index" in msbuild project files. Expressions like $(SplitVersion)[0] or @(SplitVersion)[0] or @(SplitVersion[0]) don't do what you'd think/like. If you really would to you could assign individual properties for "array elements" by "index".

Example:

<PropertyGroup>
  <SplitVersion0>$(MasterVersion.Split($(DelimitersArray))[0])</SplitVersion0>
  <SplitVersion1>$(MasterVersion.Split($(DelimitersArray))[1])</SplitVersion1>
  <SplitVersion2>$(MasterVersion.Split($(DelimitersArray))[2])</SplitVersion2>
</PropertyGroup>

The array-indexing operator works here, because in this case you are still "in the context" of the .NET expression. Once that is assigned to a property (or item group) you cannot do that anymore.