File: PreviewPane\PreviewPane.xaml.cs
Web Access
Project: src\src\VisualStudio\Core\Def\Microsoft.VisualStudio.LanguageServices_1q2bu2xg_wpftmp.csproj (Microsoft.VisualStudio.LanguageServices)
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
#nullable disable
 
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Navigation;
using Microsoft.CodeAnalysis.Diagnostics.Log;
using Microsoft.CodeAnalysis.Editor.Implementation.Preview;
using Microsoft.VisualStudio.LanguageServices.Implementation.Utilities;
using Microsoft.VisualStudio.OLE.Interop;
using Microsoft.VisualStudio.Shell;
using Microsoft.VisualStudio.Shell.Interop;
using Roslyn.Utilities;
using IVsUIShell = Microsoft.VisualStudio.Shell.Interop.IVsUIShell;
using OLECMDEXECOPT = Microsoft.VisualStudio.OLE.Interop.OLECMDEXECOPT;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.PreviewPane;
 
internal partial class PreviewPane : UserControl, IDisposable, IOleCommandTarget
{
    private const double DefaultWidth = 400;
 
    private static readonly string s_dummyThreeLineTitle = "A" + Environment.NewLine + "A" + Environment.NewLine + "A";
    private static readonly Size s_infiniteSize = new(double.PositiveInfinity, double.PositiveInfinity);
 
    private readonly string _id;
    private readonly bool _logIdVerbatimInTelemetry;
    private readonly IVsUIShell _uiShell;
 
    private bool _isExpanded;
    private readonly double _heightForThreeLineTitle;
 
    private DifferenceViewerPreview _differenceViewerPreview;
    private readonly IVsRegisterPriorityCommandTarget _registerPriorityCommandTarget;
    private readonly uint _commandTargetCookie = VSConstants.VSCOOKIE_NIL;
 
    public PreviewPane(
        Image severityIcon,
        string id,
        string title,
        string description,
        Uri helpLink,
        string helpLinkToolTipText,
        IReadOnlyList<object> previewContent,
        bool logIdVerbatimInTelemetry,
        IVsUIShell uiShell,
        Guid optionPageGuid = default)
    {
        InitializeComponent();
 
        Loaded += PreviewPane_Loaded;
 
        _id = id;
        _logIdVerbatimInTelemetry = logIdVerbatimInTelemetry;
        _uiShell = uiShell;
 
        // Initialize header portion.
        if ((severityIcon != null) && !string.IsNullOrWhiteSpace(id) && !string.IsNullOrWhiteSpace(title))
        {
            HeaderStackPanel.Visibility = Visibility.Visible;
 
            SeverityIconBorder.Child = severityIcon;
 
            // Set the initial title text to three lines worth so that we can measure the pixel height
            // that WPF requires to render three lines of text under the current font and DPI settings.
            TitleRun.Text = s_dummyThreeLineTitle;
            TitleTextBlock.Measure(availableSize: s_infiniteSize);
            _heightForThreeLineTitle = TitleTextBlock.DesiredSize.Height;
 
            // Now set the actual title text.
            TitleRun.Text = title;
 
            if (helpLink != null)
            {
                Contract.ThrowIfNull(helpLinkToolTipText);
                InitializeHyperlinks(helpLink, helpLinkToolTipText);
            }
 
            if (!string.IsNullOrWhiteSpace(description))
            {
                DescriptionParagraph.Inlines.Add(description);
            }
        }
 
        _optionPageGuid = optionPageGuid;
 
        if (optionPageGuid == default)
        {
            OptionsButton.Visibility = Visibility.Collapsed;
        }
 
        // Initialize preview (i.e. diff view) portion.
        InitializePreviewElement(previewContent);
 
        _registerPriorityCommandTarget = Shell.Package.GetGlobalService(typeof(SVsRegisterPriorityCommandTarget)) as IVsRegisterPriorityCommandTarget;
        Debug.Assert(_registerPriorityCommandTarget != null);
 
        if (_registerPriorityCommandTarget != null)
        {
            ErrorHandler.ThrowOnFailure(
                _registerPriorityCommandTarget.RegisterPriorityCommandTarget(
                    dwReserved: 0,
                    pCmdTrgt: this,
                    out _commandTargetCookie));
        }
    }
 
    public FrameworkElement ParentElement
    {
        get { return (FrameworkElement)GetValue(ParentElementProperty); }
        set { SetValue(ParentElementProperty, value); }
    }
 
    public static readonly DependencyProperty ParentElementProperty =
        DependencyProperty.Register("ParentElement", typeof(FrameworkElement), typeof(PreviewPane), new PropertyMetadata(null));
 
    private void PreviewPane_Loaded(object sender, RoutedEventArgs e)
    {
        Loaded -= PreviewPane_Loaded;
        ParentElement = Parent as FrameworkElement;
    }
 
    public string AutomationName => ServicesVSResources.Preview_pane;
 
    private void InitializePreviewElement(IReadOnlyList<object> previewItems)
    {
        var previewElement = CreatePreviewElement(previewItems);
 
        if (previewElement != null)
        {
            HeaderSeparator.Visibility = Visibility.Visible;
            PreviewDockPanel.Visibility = Visibility.Visible;
            PreviewScrollViewer.Content = previewElement;
            previewElement.VerticalAlignment = VerticalAlignment.Top;
            previewElement.HorizontalAlignment = HorizontalAlignment.Left;
        }
 
        // 1. Width of the header section should not exceed the width of the preview content.
        // In other words, the text we put in the header at the top of the preview pane
        // should not cause the preview pane itself to grow wider than the width required to
        // display the preview content at the bottom of the pane.
        // 2. Adjust the height of the header section so that it displays only three lines worth
        // by default.
        AdjustWidthAndHeight(previewElement);
    }
 
    private FrameworkElement CreatePreviewElement(IReadOnlyList<object> previewItems)
    {
        if (previewItems == null || previewItems.Count == 0)
        {
            return null;
        }
 
        const int MaxItems = 3;
        if (previewItems.Count > MaxItems)
        {
            previewItems = previewItems.Take(MaxItems).Concat("...").ToList();
        }
 
        var grid = new Grid();
 
        foreach (var previewItem in previewItems)
        {
            var previewElement = GetPreviewElement(previewItem);
 
            // no preview element
            if (previewElement == null)
            {
                continue;
            }
 
            // the very first preview
            if (grid.RowDefinitions.Count == 0)
            {
                grid.RowDefinitions.Add(new RowDefinition());
            }
            else
            {
                grid.RowDefinitions.Add(new RowDefinition() { Height = GridLength.Auto });
            }
 
            // set row position of the element
            Grid.SetRow(previewElement, grid.RowDefinitions.Count - 1);
 
            // add the element to the grid
            grid.Children.Add(previewElement);
 
            // set width of the grid same as the first element
            if (grid.Children.Count == 1)
            {
                grid.Width = previewElement.Width;
            }
        }
 
        if (grid.Children.Count == 0)
        {
            // no preview
            return null;
        }
 
        // if there is only 1 item, just take preview element as it is without grid
        if (grid.Children.Count == 1)
        {
            var preview = grid.Children[0];
 
            // we need to take it out from visual tree
            grid.Children.Clear();
 
            return (FrameworkElement)preview;
        }
 
        return grid;
    }
 
    private FrameworkElement GetPreviewElement(object previewItem)
    {
        if (previewItem is DifferenceViewerPreview)
        {
            // Contract is there should be only 1 diff viewer, otherwise we leak.
            Contract.ThrowIfFalse(_differenceViewerPreview == null);
 
            // cache the diff viewer so that we can close it when panel goes away.
            // this is a bit weird since we are mutating state here.
            _differenceViewerPreview = (DifferenceViewerPreview)previewItem;
            var viewer = _differenceViewerPreview.Viewer;
            PreviewDockPanel.Background = viewer.InlineView.Background;
 
            var previewElement = viewer.VisualElement;
            return previewElement;
        }
 
        if (previewItem is string s)
        {
            return GetPreviewForString(s);
        }
 
        if (previewItem is FrameworkElement frameworkElement)
        {
            return frameworkElement;
        }
 
        // preview item we don't know how to show to users
        return null;
    }
 
    private void InitializeHyperlinks(Uri helpLink, string helpLinkToolTipText)
    {
        IdHyperlink.Inlines.Add(_id);
        IdHyperlink.NavigateUri = helpLink;
        IdHyperlink.IsEnabled = true;
        IdHyperlink.ToolTip = helpLinkToolTipText;
 
        LearnMoreHyperlink.Inlines.Add(string.Format(ServicesVSResources.More_about_0, _id));
        LearnMoreHyperlink.NavigateUri = helpLink;
        LearnMoreHyperlink.ToolTip = helpLinkToolTipText;
    }
 
    private static FrameworkElement GetPreviewForString(string previewContent)
    {
        return new TextBlock()
        {
            Margin = new Thickness(5),
            VerticalAlignment = VerticalAlignment.Center,
            Text = previewContent,
            TextWrapping = TextWrapping.Wrap,
        };
    }
 
    // This method adjusts the width of the header section to match that of the preview content
    // thereby ensuring that the preview pane itself is never wider than the preview content.
    // This method also adjusts the height of the header section so that it displays only three lines
    // worth by default.
    private void AdjustWidthAndHeight(FrameworkElement previewElement)
    {
        double headerStackPanelWidth;
        var titleTextBlockHeight = double.PositiveInfinity;
        if (previewElement == null)
        {
            HeaderStackPanel.Measure(availableSize: s_infiniteSize);
            headerStackPanelWidth = HeaderStackPanel.DesiredSize.Width;
 
            TitleTextBlock.Measure(availableSize: s_infiniteSize);
            titleTextBlockHeight = TitleTextBlock.DesiredSize.Height;
        }
        else
        {
            PreviewDockPanel.Measure(availableSize: new Size(
                double.IsNaN(previewElement.Width) ? DefaultWidth : previewElement.Width,
                double.PositiveInfinity));
            headerStackPanelWidth = PreviewDockPanel.DesiredSize.Width;
            if (IsNormal(headerStackPanelWidth))
            {
                TitleTextBlock.Measure(availableSize: new Size(headerStackPanelWidth, double.PositiveInfinity));
                titleTextBlockHeight = TitleTextBlock.DesiredSize.Height;
            }
        }
 
        if (IsNormal(headerStackPanelWidth))
        {
            HeaderStackPanel.Width = headerStackPanelWidth;
        }
 
        // If the pixel height required to render the complete title in the
        // TextBlock is larger than that required to render three lines worth,
        // then trim the contents of the TextBlock with an ellipsis at the end and
        // display the expander button that will allow users to view the full text.
        if (HasDescription || (IsNormal(titleTextBlockHeight) && (titleTextBlockHeight > _heightForThreeLineTitle)))
        {
            TitleTextBlock.MaxHeight = _heightForThreeLineTitle;
            TitleTextBlock.TextTrimming = TextTrimming.CharacterEllipsis;
 
            ExpanderToggleButton.Visibility = Visibility.Visible;
 
            if (_isExpanded)
            {
                ExpanderToggleButton.IsChecked = true;
            }
        }
    }
 
    private static bool IsNormal(double size)
        => size > 0 && !double.IsNaN(size) && !double.IsInfinity(size);
 
    private bool HasDescription
    {
        get
        {
            return DescriptionParagraph.Inlines.Count > 0;
        }
    }
 
    private readonly Guid _optionPageGuid;
    void IDisposable.Dispose()
    {
        // VS editor will call Dispose at which point we should Close() the embedded IWpfDifferenceViewer.
        _differenceViewerPreview?.Dispose();
        _differenceViewerPreview = null;
 
        if (_registerPriorityCommandTarget != null && _commandTargetCookie != VSConstants.VSCOOKIE_NIL)
        {
            _registerPriorityCommandTarget.UnregisterPriorityCommandTarget(_commandTargetCookie);
        }
    }
 
    int IOleCommandTarget.QueryStatus(ref Guid pguidCmdGroup, uint cCmds, OLECMD[] prgCmds, IntPtr pCmdText)
    {
        ThreadHelper.ThrowIfNotOnUIThread();
        if (_differenceViewerPreview != null)
        {
            return _differenceViewerPreview.QueryStatus(ref pguidCmdGroup, cCmds, prgCmds, pCmdText);
        }
 
        return VSConstants.S_OK;
    }
 
    int IOleCommandTarget.Exec(ref Guid pguidCmdGroup, uint nCmdID, uint nCmdexecopt, IntPtr pvaIn, IntPtr pvaOut)
    {
        ThreadHelper.ThrowIfNotOnUIThread();
        if (_differenceViewerPreview != null)
        {
            return _differenceViewerPreview.Exec(ref pguidCmdGroup, nCmdID, nCmdexecopt, pvaIn, pvaOut);
        }
 
        return (int)VisualStudio.OLE.Interop.Constants.OLECMDERR_E_UNKNOWNGROUP;
    }
 
    private void LearnMoreHyperlink_RequestNavigate(object sender, RequestNavigateEventArgs e)
    {
        if (e.Uri == null)
        {
            return;
        }
 
        VisualStudioNavigateToLinkService.StartBrowser(e.Uri);
        e.Handled = true;
 
        if (sender is not Hyperlink hyperlink)
        {
            return;
        }
 
        DiagnosticLogger.LogHyperlink(hyperlink.Name ?? "Preview", _id, HasDescription, _logIdVerbatimInTelemetry, e.Uri.AbsoluteUri);
    }
 
    private void ExpanderToggleButton_CheckedChanged(object sender, RoutedEventArgs e)
    {
        if (ExpanderToggleButton.IsChecked ?? false)
        {
            TitleTextBlock.MaxHeight = double.PositiveInfinity;
            TitleTextBlock.TextTrimming = TextTrimming.None;
 
            if (HasDescription)
            {
                DescriptionDockPanel.Visibility = Visibility.Visible;
 
                if (LearnMoreHyperlink.NavigateUri != null)
                {
                    LearnMoreTextBlock.Visibility = Visibility.Visible;
                    LearnMoreHyperlink.IsEnabled = true;
                }
            }
 
            _isExpanded = true;
        }
        else
        {
            TitleTextBlock.MaxHeight = _heightForThreeLineTitle;
            TitleTextBlock.TextTrimming = TextTrimming.CharacterEllipsis;
 
            DescriptionDockPanel.Visibility = Visibility.Collapsed;
 
            _isExpanded = false;
        }
    }
 
    private void OptionsButton_Click(object sender, RoutedEventArgs e)
    {
        if (_optionPageGuid != default)
        {
            ErrorHandler.ThrowOnFailure(_uiShell.PostExecCommand(
                VSConstants.GUID_VSStandardCommandSet97,
                (uint)VSConstants.VSStd97CmdID.ToolsOptions,
                (uint)OLECMDEXECOPT.OLECMDEXECOPT_DODEFAULT,
                _optionPageGuid.ToString()));
        }
    }
}