UpgradeCsprojFramework

[Reflection.Assembly]::LoadWithPartialName("System.Xml.Linq") | Out-Null

#specify the root of your source tree below
$path = "C:\Code\chatsworth"

$ns = "http://schemas.microsoft.com/developer/msbuild/2003"
$xname = [System.Xml.Linq.XName]::Get("PropertyGroup",$ns)
$tfname = [System.Xml.Linq.XName]::Get("TargetFrameworkVersion",$ns)
	
$xws = New-Object System.Xml.XmlWriterSettings
$xws.OmitXmlDeclaration = $true
$xws.Indent = $true

function updatefx($filename)
{
	#Write-Host $filename
	$xml = [System.Xml.Linq.XDocument]::Load($filename)
	
 	$result = $xml.Descendants($xname)
	
	foreach ($i in $result)
	{
		$fxelem = $i.Element($tfname)
		if($fxelem)
		{
			$i.SetElementValue($tfname,"v4.0")
		}
	}

	$xw = [System.Xml.XmlWriter]::Create($filename, $xws)
	$xml.Save($xw)
	$xw.Close()
}

$csprojs = Get-ChildItem $path *.csproj -Recurse

foreach ($file in $csprojs)
{
	updatefx $file.FullName
}