Implemented Win32 version of file dialog

src/Perspex.Controls/CommonDialog.cs

@@ -0,0 +1,34 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Perspex.Controls.Platform;
+using Splat;
+
+namespace Perspex.Controls
+{
+    public class CommonDialog
+    {
+        public string Title { get; set; }
+        public List<CommonDialogFilter> Filters { get; set; } = new List<CommonDialogFilter>();
+        public string InitialFileName { get; set; }
+        public string InitialDirectory { get; set; }
+        public bool AllowMultiple { get; set; }
+        public string DefaultExtension { get; set; }
+        public CommonDialogAction Action { get; set; }
+
+
+        public Task<string[]> ShowAsync(Window window = null) 
+            => Locator.Current.GetService<ICommonDialogImpl>().ShowAsync(this, window?.PlatformImpl);
+    }
+
+    public enum CommonDialogAction
+    {
+        OpenFile,
+        SaveFile
+    }
+
+    public class CommonDialogFilter
+    {
+        public string Name { get; set; }
+        public List<string> Extensions { get; set; } = new List<string>();
+    }
+}

src/Perspex.Controls/Perspex.Controls.csproj

@@ -41,6 +41,7 @@
     <Compile Include="..\Shared\SharedAssemblyInfo.cs">
       <Link>Properties\SharedAssemblyInfo.cs</Link>
     </Compile>
+    <Compile Include="CommonDialog.cs" />
     <Compile Include="DockPanel\Aligner.cs" />
     <Compile Include="DockPanel\Alignment.cs" />
     <Compile Include="DockPanel\Alignments.cs" />
@@ -64,6 +65,7 @@
     <Compile Include="Margins.cs" />
     <Compile Include="MenuItemAccessKeyHandler.cs" />
     <Compile Include="Mixins\SelectableMixin.cs" />
+    <Compile Include="Platform\ICommonDialogImpl.cs" />
     <Compile Include="Presenters\IContentPresenter.cs" />
     <Compile Include="Primitives\AccessText.cs" />
     <Compile Include="Border.cs" />

src/Perspex.Controls/Platform/ICommonDialogImpl.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Perspex.Platform;
+
+namespace Perspex.Controls.Platform
+{
+    public interface ICommonDialogImpl
+    {
+        Task<string[]> ShowAsync(CommonDialog dialog, IWindowImpl parent);
+    }
+}

src/Windows/Perspex.Win32/CommonDialogImpl.cs

@@ -0,0 +1,117 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+using Perspex.Controls;
+using Perspex.Controls.Platform;
+using Perspex.Platform;
+using Perspex.Win32.Interop;
+
+namespace Perspex.Win32
+{
+    class CommonDialogImpl : ICommonDialogImpl
+    {
+        public unsafe Task<string[]> ShowAsync(CommonDialog dialog, IWindowImpl parent)
+        {
+            var hWnd = parent?.Handle?.Handle ?? IntPtr.Zero;
+            return Task.Factory.StartNew(() =>
+            {
+                var filters = new StringBuilder();
+                foreach (var filter in dialog.Filters)
+                {
+                    var extMask = string.Join(";", filter.Extensions.Select(e => "*." + e));
+                    filters.Append(filter.Name);
+                    filters.Append(" (");
+                    filters.Append(extMask);
+                    filters.Append(")");
+                    filters.Append('\0');
+                    filters.Append(extMask);
+                    filters.Append('\0');
+                }
+                if (filters.Length == 0)
+                    filters.Append("All files\0*.*\0");
+                filters.Append('\0');
+
+                var filterBuffer = new char[filters.Length];
+                filters.CopyTo(0, filterBuffer, 0, filterBuffer.Length);
+
+
+                var buffer = new char[256];
+                fixed (char* pBuffer = buffer)
+                fixed (char* pFilterBuffer = filterBuffer)
+                fixed (char* pDefExt = dialog.DefaultExtension)
+                fixed (char* pInitDir = dialog.InitialDirectory)
+                fixed (char* pTitle = dialog.Title)
+                {
+
+                    var ofn = new UnmanagedMethods.OpenFileName()
+                    {
+                        hwndOwner = hWnd,
+                        hInstance = IntPtr.Zero,
+                        lCustData = IntPtr.Zero,
+                        nFilterIndex = 0,
+                        Flags =
+                            UnmanagedMethods.OpenFileNameFlags.OFN_EXPLORER |
+                            UnmanagedMethods.OpenFileNameFlags.OFN_HIDEREADONLY,
+                        nMaxCustFilter = 0,
+                        nMaxFile = buffer.Length - 1,
+                        nMaxFileTitle = 0,
+                        lpTemplateName = IntPtr.Zero,
+                        lpfnHook = IntPtr.Zero,
+                        lpstrCustomFilter = IntPtr.Zero,
+                        lpstrDefExt = new IntPtr(pDefExt),
+                        lpstrFile = new IntPtr(pBuffer),
+                        lpstrFileTitle = IntPtr.Zero,
+                        lpstrFilter = new IntPtr(pFilterBuffer),
+                        lpstrInitialDir = new IntPtr(pInitDir),
+                        lpstrTitle = new IntPtr(pTitle),
+
+                    };
+                    ofn.lStructSize = Marshal.SizeOf(ofn);
+                    if (dialog.AllowMultiple && dialog.Action == CommonDialogAction.OpenFile)
+                        ofn.Flags |= UnmanagedMethods.OpenFileNameFlags.OFN_ALLOWMULTISELECT;
+
+                    if (dialog.Action == CommonDialogAction.SaveFile)
+                        ofn.Flags |= UnmanagedMethods.OpenFileNameFlags.OFN_NOREADONLYRETURN |
+                                     UnmanagedMethods.OpenFileNameFlags.OFN_OVERWRITEPROMPT;
+
+                    var pofn = &ofn;
+
+                    var res = dialog.Action == CommonDialogAction.OpenFile
+                        ? UnmanagedMethods.GetOpenFileName(new IntPtr(pofn))
+                        : UnmanagedMethods.GetSaveFileName(new IntPtr(pofn));
+                    if (!res)
+                        return null;
+
+                }
+                var cStart = 0;
+                string dir = null;
+                var files = new List<string>();
+                for (var c = 0; c < buffer.Length; c++)
+                {
+                    if (buffer[c] == 0)
+                    {
+                        //Encountered double zero char
+                        if (cStart == c)
+                            break;
+
+                        var s = new string(buffer, cStart, c - cStart);
+                        if (dir == null)
+                            dir = s;
+                        else
+                            files.Add(s);
+                        cStart = c + 1;
+                    }
+                }
+                if (files.Count == 0)
+                    return new[] {dir};
+
+                return files.Select(f => Path.Combine(dir, f)).ToArray();
+            });
+        }
+    }
+}

src/Windows/Perspex.Win32/Interop/UnmanagedMethods.cs

@@ -6,6 +6,7 @@ using System.Diagnostics.CodeAnalysis;
 using System.Runtime.InteropServices;
 using System.Text;
 // ReSharper disable InconsistentNaming
+#pragma warning disable 169
 
 namespace Perspex.Win32.Interop
 {
@@ -677,7 +678,14 @@ namespace Perspex.Win32.Interop
         [DllImport("kernel32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
         public static extern IntPtr GlobalFree(IntPtr hMem);
 
+        [DllImport("comdlg32.dll", CharSet = CharSet.Unicode, EntryPoint = "GetSaveFileNameW")]
+        public static extern bool GetSaveFileName(IntPtr lpofn);
 
+        [DllImport("comdlg32.dll", CharSet = CharSet.Unicode, EntryPoint = "GetOpenFileNameW")]
+        public static extern bool GetOpenFileName(IntPtr lpofn);
+
+        [DllImport("comdlg32.dll")]
+        public static extern int CommDlgExtendedError();
 
         public enum ClipboardFormat
         {
@@ -745,5 +753,49 @@ namespace Perspex.Win32.Interop
             public string lpszClassName;
             public IntPtr hIconSm;
         }
+
+        [Flags]
+        public enum OpenFileNameFlags
+        {
+
+            OFN_ALLOWMULTISELECT = 0x00000200,
+
+            OFN_EXPLORER = 0x00080000,
+
+            OFN_HIDEREADONLY = 0x00000004,
+
+            OFN_NOREADONLYRETURN = 0x00008000,
+
+            OFN_OVERWRITEPROMPT = 0x00000002
+
+        }
+
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+        public struct OpenFileName
+        {
+            public int lStructSize;
+            public IntPtr hwndOwner;
+            public IntPtr hInstance;
+            public IntPtr lpstrFilter;
+            public IntPtr lpstrCustomFilter;
+            public int nMaxCustFilter;
+            public int nFilterIndex;
+            public IntPtr lpstrFile;
+            public int nMaxFile;
+            public IntPtr lpstrFileTitle;
+            public int nMaxFileTitle;
+            public IntPtr lpstrInitialDir;
+            public IntPtr lpstrTitle;
+            public OpenFileNameFlags Flags;
+            private ushort Unused;
+            private ushort Unused2;
+            public IntPtr lpstrDefExt;
+            public IntPtr lCustData;
+            public IntPtr lpfnHook;
+            public IntPtr lpTemplateName;
+            public IntPtr reservedPtr;
+            public int reservedInt;
+            public int flagsEx;
+        }
     }
 }

src/Windows/Perspex.Win32/Perspex.Win32.csproj

@@ -23,6 +23,7 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <DocumentationFile>bin\Debug\Perspex.Win32.XML</DocumentationFile>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -32,6 +33,7 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <DocumentationFile>bin\Release\Perspex.Win32.XML</DocumentationFile>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
@@ -65,6 +67,7 @@
       <Link>Properties\SharedAssemblyInfo.cs</Link>
     </Compile>
     <Compile Include="ClipboardImpl.cs" />
+    <Compile Include="CommonDialogImpl.cs" />
     <Compile Include="CursorFactory.cs" />
     <Compile Include="Input\KeyInterop.cs" />
     <Compile Include="Input\WindowsKeyboardDevice.cs" />

src/Windows/Perspex.Win32/Win32Platform.cs

@@ -8,6 +8,7 @@ using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Reactive.Disposables;
 using System.Runtime.InteropServices;
+using Perspex.Controls.Platform;
 using Perspex.Input;
 using Perspex.Platform;
 using Perspex.Shared.PlatformSupport;
@@ -41,6 +42,7 @@ namespace Perspex.Win32
         private static void InitializeInternal()
         {
             var locator = Locator.CurrentMutable;
+            locator.Register(() => new CommonDialogImpl(), typeof (ICommonDialogImpl));
             locator.Register(() => new PopupImpl(), typeof(IPopupImpl));
             locator.Register(() => new ClipboardImpl(), typeof(IClipboard));
             locator.Register(() => WindowsKeyboardDevice.Instance, typeof(IKeyboardDevice));