pinvoke.net: Edit: shell32.SHGetSpecialFolderPath

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@pinvoke=http://pinvoke.net/$$$.htm

Summary: The SHGetSpecialFolderPath API

!!!!C# Signature:
  [DllImport("Shell32.dll", CharSet=CharSet.Unicode)]
   static extern int SHGetSpecialFolderPath(IntPtr hwndOwner, IntPtr lpszPath, int nFolder, int fCreate);

!!!!VB Signature:
 <DllImport("Shell32.dll")> Shared Function SHGetSpecialFolderPath(ByVal hwndOwner As IntPtr,
   <Out()> ByVal lpszPath As IntPtr, ByVal nFolder As Integer, ByVal fCreate As Boolean) As Boolean
 End Function

!!!!User-Defined Types:
None.

!!!!Notes:
lpszPath must be at least MAX_PATH (260) characters in size.

!!!!Tips & Tricks:
Please add some!

!!!!Sample Code:
   int CSIDL_MYMUSIC = 0x000d;
   IntPtr path = Marshal.AllocHGlobal(260 * 2);	// UNICODE
   SHGetSpecialFolderPath(parent.Handle, path, CSIDL_MYMUSIC, 0);
   
   string myMusicDir = Marshal.PtrToStringUni(path);
   //? Marshal.FreeHGlobal(path);
!!!!Alternative Managed API:

Environment.GetFolderPath(Environment.SpecialFolder.xxx) probably calls this internally - it does the same thing. 
However not all of the enums are available (e.g. CSIDL_COMMON_DOCUMENTS missing on .NET 1.1) therefore this is needed sometimes.

Documentation: SHGetSpecialFolderPath@msdn on MSDN

!!! 'Managed API Using Shell32.dll
(VB)

Public Shared Function SpecialFolderPathSH32(csidl As Integer, _
   Optional ByRef DisplayName As String = "", _
	Optional ByRef TypeName As String = "") As String

Dim path As String = ""
		Dim sh As New Shell32.Shell

If csidl <> CInt(Environment.SpecialFolder.MyComputer) _
		 AndAlso [Enum].IsDefined(GetType(Environment.SpecialFolder), csidl) Then
			Dim f2 As Shell32.Folder2 = TryCast(sh.NameSpace(17), Shell32.Folder2)
			If Not IsNothing(f2) Then
				Dim shi As Shell32.FolderItem = f2.Self
				DisplayName = shi.Name
				TypeName = shi.Type
				path = shi.Path
				shi = Nothing
			End If
			Return path
			sh = Nothing
		Else
			Dim folder As Shell32.Folder = Nothing
			If csidl = 12 Then ' !!! MYDOCUMENTS
				Dim dtf As Shell32.Folder2 = CType( _
				 sh.NameSpace(Environment.SpecialFolder.Desktop), Shell32.Folder2)
				'"::{450d8fba-ad25-11d0-98a8-0800361b1103}"
				Dim fit2 As Shell32.FolderItem2 = CType( _
				 dtf.ParseName("::{450d8fba-ad25-11d0-98a8-0800361b1103}"), Shell32.FolderItem2)
				TypeName = fit2.Type
				DisplayName = fit2.Name
				path = fit2.Path
				dtf = Nothing
				sh = Nothing
				fit2 = Nothing
				Return path
			ElseIf csidl = 17 Then ' !!! MYCOMPUTER
				Dim f2 As Shell32.Folder2 = TryCast(sh.NameSpace(17), Shell32.Folder2)
				If Not IsNothing(f2) Then
					path = f2.Self.Path
					DisplayName = f2.Self.Name
					TypeName = f2.Self.Type
					f2 = Nothing
				End If
				sh = Nothing
				Return path
			Else
				folder = sh.NameSpace(csidl)
				'End If
				Dim folder2 As Shell32.Folder2 = TryCast(folder, Shell32.Folder2)
				If Not IsNothing(folder2) Then
					path = folder2.Self.Path
					DisplayName = folder2.Title
					TypeName = folder2.Self.Type
				End If
				End If
			sh = Nothing
				Return path
			End If
	End Function