CalculatePackageVersion.ps1

$Prefix = Get-ChildItem -Recurse -Depth 2 -Filter *.csproj `
  | ForEach-Object { [Xml]$A = $_ | Get-Content; $A.Project.PropertyGroup.VersionPrefix } `
  | Where-Object { $_ -ne $null -and $_ -ne '' } `
  | Select-Object -First 1

If ($IsBeta -eq "1") {
  $Parts = $BuildNumber.Split('.')
  $Date = $Parts[0]
  $Sequence = $Parts[1] / 1
  $Suffix = "-beta" + $Date + $Sequence.ToString("000")
}
Else {
  $Suffix = ""
}
Write-Host "Using Package Version $Prefix$Suffix"
Write-Host "##vso[task.setvariable variable=PackageVersion;]$Prefix$Suffix"