Merge pull request #8202 from workgroupengineering/features/Skia/WPF/…

…FolderPicker

feat(FolderPicker): [Skia][WPF] Added support at SuggestedStartLocati…

src/Uno.UI.Runtime.Skia.Wpf/Extensions/Storage/Pickers/FolderPickerExtension.cs

@@ -4,7 +4,6 @@
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
-using Uno.UI.Runtime.Skia;
 using Windows.Storage;
 using Windows.Storage.Pickers;
 
@@ -14,17 +13,36 @@ internal class FolderPickerExtension : IFolderPickerExtension
 	{
 		private readonly FolderPicker _picker;
 
+		public Guid? SuggestedStartLocation { get; private set; }
+
 		public FolderPickerExtension(FolderPicker owner)
 		{
 			_picker = owner ?? throw new ArgumentNullException(nameof(owner));
 		}
 
 		public async Task<StorageFolder?> PickSingleFolderAsync(CancellationToken token)
 		{
+			SuggestedStartLocation = _picker.SuggestedStartLocation switch
+			{
+				PickerLocationId.Desktop => NativeMethods.KnownFolder.Desktop,
+				PickerLocationId.HomeGroup => NativeMethods.KnownFolder.Profile,
+				PickerLocationId.Downloads => NativeMethods.KnownFolder.Downloads,
+				PickerLocationId.ComputerFolder => NativeMethods.KnownFolder.ComputerFolder,
+				PickerLocationId.DocumentsLibrary => NativeMethods.KnownFolder.DocumentsLibrary,
+				PickerLocationId.MusicLibrary => NativeMethods.KnownFolder.Music,
+				PickerLocationId.Objects3D => NativeMethods.KnownFolder.Objects3D,
+				PickerLocationId.PicturesLibrary => NativeMethods.KnownFolder.Pictures,
+				PickerLocationId.VideosLibrary => NativeMethods.KnownFolder.Videos,
+				PickerLocationId.Unspecified => default,
+				_ => throw new NotImplementedException(),
+			};
 			NativeMethods.BROWSEINFO pbi = new NativeMethods.BROWSEINFO();
 			pbi.ulFlags = 0x41; //BIF_RETURNONLYFSDIRS | BIF_NEWDIALOGSTYLE
 			pbi.pszDisplayName = new string('\0', NativeMethods.MAX_PATH);
-
+			var callback = new WndProc(FolderBrowserDialog_BrowseCallbackProc);
+			var cp = Marshal.GetFunctionPointerForDelegate(callback);
+			GC.KeepAlive(callback);
+			pbi.lpfn = cp;
 			IntPtr pidl = NativeMethods.SHBrowseForFolder(ref pbi);
 			if (pidl != IntPtr.Zero)
 			{
@@ -43,11 +61,80 @@ public FolderPickerExtension(FolderPicker owner)
 			return null;
 		}
 
+		private uint FolderBrowserDialog_BrowseCallbackProc(IntPtr hwnd, uint msg, IntPtr lParam, IntPtr lpData)
+		{
+
+			switch (msg)
+			{
+				case NativeMethods.BFFM_INITIALIZED:
+					var selectedPath = string.Empty;
+					var buttonText = _picker.CommitButtonText;
+					if (SuggestedStartLocation is Guid rfid)
+					{
+						selectedPath = NativeMethods.SHGetKnownFolderPath(rfid);
+					}
+					if (!string.IsNullOrWhiteSpace(selectedPath))
+					{
+						NativeMethods.SendMessage(new HandleRef(null, hwnd)
+							, NativeMethods.BFFM_SETSELECTION
+							, 1
+							, selectedPath);
+					}
+					if (!string.IsNullOrWhiteSpace(buttonText))
+					{
+						NativeMethods.SendMessage(new HandleRef(null, hwnd)
+							, NativeMethods.BFFM_SETOKTEXT
+							, 1
+							, buttonText);
+					}
+					break;
+				case NativeMethods.BFFM_SELCHANGED:
+					if (lParam != IntPtr.Zero)
+					{
+						var path = NativeMethods.SHGetPathFromIDListLong(lParam);
+						NativeMethods.SendMessage(new HandleRef(null, hwnd)
+							, NativeMethods.BFFM_ENABLEOK
+							, 0
+							, !string.IsNullOrWhiteSpace(path) ? 1 : 0);
+					}
+					break;
+			}
+
+			return 0;
+		}
+
+		[UnmanagedFunctionPointer(CallingConvention.Winapi)]
+		private delegate uint WndProc(IntPtr hwnd, uint msg, IntPtr lParam, IntPtr lpData);
+
 		private static class NativeMethods
 		{
+			const uint WM_USER = 0x0400;
+			internal const uint BFFM_INITIALIZED = 1;
+			internal const uint BFFM_SELCHANGED = 2;
+			private const uint BFFM_SETSELECTIONA = (WM_USER + 102);
+			private const uint BFFM_SETSELECTIONW = (WM_USER + 103);
+			internal const uint BFFM_ENABLEOK = (WM_USER + 101);
+			internal const uint BFFM_SETOKTEXT = (WM_USER + 105);
+			internal readonly static uint BFFM_SETSELECTION = Marshal.SystemDefaultCharSize == 1
+				? BFFM_SETSELECTIONA
+				: BFFM_SETSELECTIONW;
 			internal const int MAX_PATH = 260;
 			private const int MAX_LONG_PATH = 32767;
 
+			internal static class KnownFolder
+			{
+				public static readonly Guid Desktop = new Guid("B4BFCC3A-DB2C-424C-B029-7FE99A87C641");
+				public static readonly Guid Profile = new Guid("5E6C858F-0E22-4760-9AFE-EA3317B67173");
+				public static readonly Guid Downloads = new Guid("374DE290-123F-4565-9164-39C4925E467B");
+				public static readonly Guid ComputerFolder = new Guid("0AC0837C-BBF8-452A-850D-79D08E667CA7");
+				public static readonly Guid DocumentsLibrary = new Guid("7B0DB17D-9CD2-4A93-9733-46CC89022E7C");
+				public static readonly Guid Music = new Guid("4BD8D571-6D19-48D3-BE97-422220080E43");
+				public static readonly Guid Objects3D = new Guid("31C0DD25-9439-4F12-BF41-7FF4EDA38722");
+				public static readonly Guid Pictures = new Guid("33E28130-4E1E-4676-835A-98395C3BC3BB");
+				public static readonly Guid Videos = new Guid("18989B1D-99B5-455B-841C-AB7C74E4DDFC");
+			}
+
+
 			[DllImport("shell32", EntryPoint ="SHBrowseForFolderW", CharSet=CharSet.Unicode)]
 			internal static extern IntPtr SHBrowseForFolder(ref BROWSEINFO lpbi);
 
@@ -83,6 +170,34 @@ private static class NativeMethods
 			[DllImport("shell32")]
 			private static extern bool SHGetPathFromIDListEx(IntPtr pidl, IntPtr pszPath, int len, int flags);
 
+			[DllImport("user32.dll", CharSet = CharSet.Auto)]
+			internal static extern IntPtr SendMessage(HandleRef hWnd, uint msg, int wParam, string? lParam);
+
+			[DllImport("user32.dll", CharSet = CharSet.Auto)]
+			internal static extern IntPtr SendMessage(HandleRef hWnd, uint msg, int wParam, int lParam);
+
+
+			internal static string SHGetKnownFolderPath(Guid rfid, uint dwFlags = 0, IntPtr hToken = default(IntPtr))
+			{
+				IntPtr pszPath;
+				SHGetKnownFolderPath(rfid, dwFlags, hToken, out pszPath);
+
+				try
+				{
+					return Marshal.PtrToStringUni(pszPath);
+				}
+				finally
+				{
+					Marshal.FreeCoTaskMem(pszPath);
+				}
+			}
+
+			[DllImport("shell32.dll")]
+			private static extern int SHGetKnownFolderPath([MarshalAs(UnmanagedType.LPStruct)] Guid rfid,
+				uint dwFlags
+				, IntPtr hToken
+				, out IntPtr pszPath);
+
 			internal struct BROWSEINFO
 			{
 				internal IntPtr hwndOwner;