Create a custom powershell script for nuget that adds a custom target to the csproj BeforeBuild step

Question

I want to create a nuget package that adds a BeforeBuild step to my csproj using a custom MSBuild task I have created. Ideally, I want to:

1. Add a new Target int

Answer 1

The following code comes from a package called CodeAssassin.WixWebProjectReferences. It adds and removes the following import-tag to the project file upon install and uninstall. The package does not require any dependencies.

Download the package and open it using NuGetPackageExplorer to se how it's done.

Below is the code from install.ps1 and uninstall.ps1 (they are only executed if the content folder of the NuGet-package is non-empty).

(I couldn't find any powershell-highlighting so I used php instead and it's not perfect.)

install.ps1

param (
    $InstallPath,
    $ToolsPath,
    $Package,
    $Project
)

$TargetsFile = 'CodeAssassin.WixWebProjectReferences.targets'
$TargetsPath = $ToolsPath | Join-Path -ChildPath $TargetsFile

Add-Type -AssemblyName 'Microsoft.Build, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

$MSBProject = [Microsoft.Build.Evaluation.ProjectCollection]::GlobalProjectCollection.GetLoadedProjects($Project.FullName) |
    Select-Object -First 1

$ProjectUri = New-Object -TypeName Uri -ArgumentList "file://$($Project.FullName)"
$TargetUri = New-Object -TypeName Uri -ArgumentList "file://$TargetsPath"

$RelativePath = $ProjectUri.MakeRelativeUri($TargetUri) -replace '/','\'

$ExistingImports = $MSBProject.Xml.Imports |
    Where-Object { $_.Project -like "*\$TargetsFile" }
if ($ExistingImports) {
    $ExistingImports | 
        ForEach-Object {
            $MSBProject.Xml.RemoveChild($_) | Out-Null
        }
}
$MSBProject.Xml.AddImport($RelativePath) | Out-Null
$Project.Save()

uninstall.ps1

param (
    $InstallPath,
    $ToolsPath,
    $Package,
    $Project
)

$TargetsFile = 'CodeAssassin.WixWebProjectReferences.targets'

Add-Type -AssemblyName 'Microsoft.Build, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

$MSBProject = [Microsoft.Build.Evaluation.ProjectCollection]::GlobalProjectCollection.GetLoadedProjects($Project.FullName) |
    Select-Object -First 1

$ExistingImports = $MSBProject.Xml.Imports |
    Where-Object { $_.Project -like "*\$TargetsFile" }
if ($ExistingImports) {
    $ExistingImports | 
        ForEach-Object {
            $MSBProject.Xml.RemoveChild($_) | Out-Null
        }
    $Project.Save()
}

Sample targets-file that copies some files to the output path