Question

I thought this would be quite simple but then realised that I couldnt find any information on it anywhere.

I have a custom task like so:

public class MyCustomTask : Task
{
    [Required]
    public string[] SomeStrings {get;set;}

    public override bool Execute()
    {
        // Do something with strings...
    }
}

The matching MSBuild stuff is basically like so:

<UsingTask TaskName="MyCustomTask" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildBinPath)\Microsoft.Build.Tasks.v4.0.dll">
    <ParameterGroup>
      <SomeStrings ParameterType="System.String[]" Required="true" />
    </ParameterGroup>
    <Task>
    ... 
    </Task>
</UsingTask>

<Target Name="DoSomething">
    <MyCustomTask SomeStrings="????" />
</Target>

Dont have any idea of what to put in the SomeStrings parameter, thought maybe it would understand if I did “xxx,xxx,xxx” so can anyone shed any light on this. The basic scenario is alot like tokenizing so I require a list of strings then some comparison strings so I need to pass in 2 lists/arrays, but just stumped.

Answer 1

It isn’t quite clear what you are trying to do; you have the C# code for a custom task, but also the MSBuild code for the same task as an inline task — you do realize you only need to do one of those, correct? If you are trying to create a task in an assembly, the <UsingTask> in your MSBuild should be an empty element, without the <ParameterGroup> and <Task> children. If you are trying to use an inline task, you don’t need the C# code and need to specify your own assembly as the AssemblyFile, and not specify the TaskFactory as you have.

I’d declare the parameter as type ITaskItem[], so you can then pass in the value(s) as,

<MyCustomTask SomeStrings="@(SomeStrings)" />

You could set up the comparison strings as a second item array in a second parameter, or as metadata on the first parameter, e.g.

<ItemGroup>
   <SomeStrings Include="first string">
      <Comparison>first</Comparison>
   </SomeStrings>
   <SomeStrings Include="second string">
      <Comparison>2nd</Comparison>
   </SomeStrings>
</ItemGroup>

If you are using inline code, you’ll need to <Reference> the proper MSBuild assemblies and fully qualify the ParameterType. Get it working in a compiled assembly first even if your eventual intent is to use inline code.