PDFileExplorer: NavigateToFolderAsync, context menu placement and guard, hidden preview fetches nothing; .NET 10.0.15

Directory.Packages.props

@@ -10,17 +10,17 @@
     <PackageVersion Include="FluentValidation" Version="12.2.0" />
     <PackageVersion Include="Humanizer.Core" Version="3.0.10" />
     <PackageVersion Include="Markdig" Version="1.6.0" />
-    <PackageVersion Include="Microsoft.AspNetCore.Components" Version="10.0.14" />
-    <PackageVersion Include="Microsoft.AspNetCore.Components.Web" Version="10.0.14" />
-    <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly" Version="10.0.14" />
-    <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="10.0.14" />
-    <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly.Server" Version="10.0.14" />
-    <PackageVersion Include="Microsoft.AspNetCore.WebUtilities" Version="10.0.14" />
+    <PackageVersion Include="Microsoft.AspNetCore.Components" Version="10.0.15" />
+    <PackageVersion Include="Microsoft.AspNetCore.Components.Web" Version="10.0.15" />
+    <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly" Version="10.0.15" />
+    <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="10.0.15" />
+    <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly.Server" Version="10.0.15" />
+    <PackageVersion Include="Microsoft.AspNetCore.WebUtilities" Version="10.0.15" />
     <PackageVersion Include="Nerdbank.GitVersioning" Version="3.10.94" />
     <PackageVersion Include="PanoramicData.DeepCloner" Version="1.0.8" />
     <PackageVersion Include="PanoramicData.NCalcExtensions" Version="6.1.45" />
     <PackageVersion Include="Shouldly" Version="4.3.0" />
-    <PackageVersion Include="System.Drawing.Common" Version="10.0.14" />
+    <PackageVersion Include="System.Drawing.Common" Version="10.0.15" />
     <PackageVersion Include="System.Linq.Dynamic.Core" Version="1.7.4" />
     <PackageVersion Include="xunit.v3" Version="4.0.3" />
     <PackageVersion Include="bunit" Version="2.14.0" />

PanoramicData.Blazor.Demo/Pages/PDFileExplorerDocumentation.razor

@@ -64,6 +64,7 @@
 			<tbody>
 				<tr><td><code>NavigateToAsync(path)</code></td><td>Opens a folder by opening each folder above it in turn</td></tr>
 				<tr><td><code>NavigateToItemAsync(itemPath)</code></td><td>Opens the folder holding a file or folder and selects it, loading the folder's contents once. Returns false, leaving the deepest folder found open, when it is not there</td></tr>
+				<tr><td><code>NavigateToFolderAsync(folderPath)</code></td><td>Opens the folder itself, loading its contents once, without first showing the folder holding it. Returns false, leaving the deepest folder found open, when it is not there</td></tr>
 			</tbody>
 		</table>
 	</section>

PanoramicData.Blazor.Demo/Pages/PDFileExplorerPage.razor

@@ -88,6 +88,13 @@
 		<span class="small text-muted ms-2">@_showItemResult</span>
 	</div>
 
+	<div class="mt-2">
+		<strong>Open a folder:</strong>
+		<input class="form-control form-control-sm d-inline-block w-auto ms-2" aria-label="Path of the folder to open" @bind="FolderPathToOpen" />
+		<button type="button" class="btn btn-sm btn-secondary ms-1" @onclick="OpenFolderAsync">Open</button>
+		<span class="small text-muted ms-2">@_openFolderResult</span>
+	</div>
+
 	<p class="small text-muted mt-2 mb-0">
 		Navigate to <code>/Library/Templates/</code> or <code>/Sharepoint/Public/</code> to see read-only files.
 		Try different combinations to compare: position (before/after), style (text/icon), and badge overlay.

PanoramicData.Blazor.Demo/Pages/PDFileExplorerPage.razor.cs

@@ -95,6 +95,17 @@ private async Task ShowItemAsync()
 		_showItemResult = isFound ? "Selected" : "Not found: the deepest folder found is open";
 	}
 
+	private string FolderPathToOpen { get; set; } = "/Library/Templates";
+
+	private string? _openFolderResult;
+
+	// Opens the folder itself once, without first showing the folder holding it
+	private async Task OpenFolderAsync()
+	{
+		var isFound = await FileExplorer!.NavigateToFolderAsync(FolderPathToOpen).ConfigureAwait(true);
+		_openFolderResult = isFound ? "Opened" : "Not found: the deepest folder found is open";
+	}
+
 	private async Task OnReady()
 	{
 		if (!string.IsNullOrWhiteSpace(_deepLinkPath))

PanoramicData.Blazor.Test/Components/PDChatTests.Interrupt.cs

@@ -131,7 +131,7 @@ public async Task Interrupting_leaves_the_text_box_unchanged()
 	{
 		var service = InterruptService();
 		var component = await RenderSpeakingAsync(service);
-		await component.Find("textarea").InputAsync(new ChangeEventArgs { Value = "A draft" });
+		await component.InvokeAsync(() => component.Find("textarea").InputAsync(new ChangeEventArgs { Value = "A draft" }));
 
 		await SayAsync(component, Merlin);
 		await Task.Delay(_settle, Xunit.TestContext.Current.CancellationToken);

PanoramicData.Blazor.Test/Components/PDContextMenuTests.Failures.cs

@@ -0,0 +1,44 @@
+using AwesomeAssertions;
+using Bunit;
+using Microsoft.AspNetCore.Components.Web;
+using Microsoft.JSInterop;
+
+namespace PanoramicData.Blazor.Test;
+
+/// <summary>
+/// How <see cref="PDContextMenu"/> contains failures: given an ExceptionHandler, a failure in showing the menu is passed
+/// to it rather than ending the Blazor circuit, and without one it is thrown as before.
+/// </summary>
+public partial class PDContextMenuTests
+{
+	private static Task RightClickAsync(IRenderedComponent<PDContextMenu> component)
+		=> component.InvokeAsync(() => component.Find(".pdcontextmenuhost").MouseDownAsync(new MouseEventArgs { Button = 2 }));
+
+	/// <summary>A failure in showing the menu, such as its script failing, is passed to ExceptionHandler.</summary>
+	[Fact]
+	public async Task AFailureShowingTheMenu_IsPassedToTheExceptionHandler()
+	{
+		_module.SetupVoid("showMenu", _ => true).SetException(new JSException("No menu"));
+		var failures = new List<Exception>();
+		var component = Render<PDContextMenu>(parameters => parameters
+			.Add(p => p.Items, CreateItems())
+			.Add(p => p.ExceptionHandler, failures.Add)
+			.AddChildContent("<span class=\"target\">Right click me</span>"));
+
+		await RightClickAsync(component);
+
+		failures.Should().ContainSingle().Which.Message.Should().Be("No menu");
+	}
+
+	/// <summary>Without an ExceptionHandler the failure is thrown, as it always was.</summary>
+	[Fact]
+	public async Task WithoutAnExceptionHandler_AFailureShowingTheMenu_IsThrownAsBefore()
+	{
+		_module.SetupVoid("showMenu", _ => true).SetException(new JSException("No menu"));
+		var component = RenderMenu(null);
+
+		var act = () => RightClickAsync(component);
+
+		await act.Should().ThrowAsync<JSException>().WithMessage("No menu");
+	}
+}

PanoramicData.Blazor.Test/Components/PDFileExplorerTests.Failures.cs

@@ -92,4 +92,17 @@ public async Task NavigateToItemAsync_ALaterCall_SupersedesOneStillLoading()
 		cut.Instance.SelectedFilesAndFolders.Should().Equal("/Media/pic.png");
 		cut.Instance.IsNavigating.Should().BeFalse();
 	}
+
+	/// <summary>The tree's and table's right-click menus pass their failures on as the explorer does.</summary>
+	[Fact]
+	public void TheContextMenus_PassFailuresOn_OnlyWhenTheApplicationGivesAHandler()
+	{
+		var withHandler = RenderExplorer();
+		var withoutHandler = Render<PDFileExplorer>(p => p.Add(x => x.DataProvider, _provider));
+
+		withHandler.FindComponents<PDContextMenu>().Should().HaveCount(2)
+			.And.AllSatisfy(menu => menu.Instance.ExceptionHandler.HasDelegate.Should().BeTrue());
+		withoutHandler.FindComponents<PDContextMenu>().Should().HaveCount(2)
+			.And.AllSatisfy(menu => menu.Instance.ExceptionHandler.HasDelegate.Should().BeFalse());
+	}
 }

PanoramicData.Blazor.Test/Components/PDFileExplorerTests.Navigation.cs

@@ -162,6 +162,74 @@ public async Task NavigateToItemAsync_NoItem_DoesNothing(string path)
 		cut.Instance.FolderPath.Should().Be("/Docs");
 	}
 
+	/// <summary>Navigating to a folder opens it once, without opening the folders above it or first showing its parent.</summary>
+	[Fact]
+	public async Task NavigateToFolderAsync_OpensOnlyTheFolder()
+	{
+		_provider.Items.Remove(_provider.Get("/Docs/Sub"));
+		_provider.Items.AddRange(
+		[
+			FileProvider.Dir("/Docs/Sub", hasSubFolders: true),
+			FileProvider.Dir("/Docs/Sub/Deep"),
+			FileProvider.File("/Docs/Sub/Deep/report.pdf", 100)
+		]);
+		var folders = new List<string>();
+		var cut = RenderExplorer(p => p.Add(x => x.FolderChanged, (FileExplorerItem f) => folders.Add(f.Path)));
+		await NavigateAsync(cut, "/Media");
+		folders.Clear();
+		_provider.Requests.Clear();
+
+		var found = await cut.InvokeAsync(() => cut.Instance.NavigateToFolderAsync("/Docs/Sub/Deep"));
+
+		found.Should().BeTrue();
+		cut.Instance.FolderPath.Should().Be("/Docs/Sub/Deep");
+		folders.Should().Equal("/Docs/Sub/Deep");
+		_provider.Requests.Should().Equal("/Docs", "/Docs/Sub", "/Docs/Sub/Deep");
+		Tree(cut).Instance.SelectedNode!.Key.Should().Be("/Docs/Sub/Deep");
+		cut.Instance.SelectedFilesAndFolders.Should().BeEmpty();
+		RowNames(cut).Should().Equal("..", "report.pdf");
+		cut.Instance.IsNavigating.Should().BeFalse();
+	}
+
+	/// <summary>A missing folder on the way stops at the deepest folder found.</summary>
+	[Fact]
+	public async Task NavigateToFolderAsync_AMissingFolder_OpensTheDeepestFolderFound_AndReturnsFalse()
+	{
+		var cut = RenderExplorer();
+
+		var found = await cut.InvokeAsync(() => cut.Instance.NavigateToFolderAsync("/Docs/Gone"));
+
+		found.Should().BeFalse();
+		cut.Instance.FolderPath.Should().Be("/Docs");
+		cut.Instance.IsNavigating.Should().BeFalse();
+	}
+
+	/// <summary>The root is a folder, so it can be opened.</summary>
+	[Fact]
+	public async Task NavigateToFolderAsync_TheRoot_OpensIt()
+	{
+		var cut = RenderExplorer();
+		await NavigateAsync(cut, "/Docs");
+
+		var found = await cut.InvokeAsync(() => cut.Instance.NavigateToFolderAsync("/"));
+
+		found.Should().BeTrue();
+		cut.Instance.FolderPath.Should().Be("/");
+	}
+
+	/// <summary>A blank path is ignored.</summary>
+	[Fact]
+	public async Task NavigateToFolderAsync_ABlankPath_DoesNothing()
+	{
+		var cut = RenderExplorer();
+		await NavigateAsync(cut, "/Docs");
+
+		var found = await cut.InvokeAsync(() => cut.Instance.NavigateToFolderAsync(" "));
+
+		found.Should().BeFalse();
+		cut.Instance.FolderPath.Should().Be("/Docs");
+	}
+
 	/// <summary>SelectedFilesAndFolders lists the selected paths, and SelectionChanged carries the selected items.</summary>
 	[Fact]
 	public async Task Selection_IsReportedToTheApplication()

PanoramicData.Blazor.Test/Components/PDFileExplorerTests.Preview.cs

@@ -120,4 +120,33 @@ public async Task PreviewKey_WhenNotOptional_DoesNothing()
 		cut.Instance.PreviewPanelVisible.Should().BeTrue();
 		_splitter.Invocations["setSizes"].Should().BeEmpty();
 	}
+
+	/// <summary>A hidden preview fetches nothing; shown again, it fetches the row chosen while it was hidden.</summary>
+	[Fact]
+	public async Task OptionalOn_AHiddenPreview_FetchesOnlyOnceShown()
+	{
+		var provider = new RecordingPreviewProvider();
+		var cut = RenderExplorer(p => p
+			.Add(x => x.PreviewPanel, FilePreviewModes.OptionalOn)
+			.Add(x => x.PreviewProvider, provider));
+		await ClickToolbarAsync(cut, "preview");
+		provider.PreviewedPaths.Clear();
+
+		await SelectRowsAsync(cut, "/Docs");
+		provider.PreviewedPaths.Should().BeEmpty();
+
+		await ClickToolbarAsync(cut, "preview");
+		cut.WaitForAssertion(() => provider.PreviewedPaths.Should().Equal("/Docs"));
+	}
+
+	private sealed class RecordingPreviewProvider : DefaultPreviewProvider
+	{
+		public List<string?> PreviewedPaths { get; } = [];
+
+		public override Task<PreviewInfo> GetPreviewInfoAsync(FileExplorerItem? item)
+		{
+			PreviewedPaths.Add(item?.Path);
+			return base.GetPreviewInfoAsync(item);
+		}
+	}
 }

PanoramicData.Blazor.Test/Components/PDFilePreviewTests.cs

@@ -153,6 +153,23 @@ public void A_failing_preview_falls_back_and_reports_the_exception()
 	/// A preview provider returning a fixed result, recording which items are previewed and how often a spinner is asked for.
 	/// Both timings are zero so the spinner path is decided by whether the preview task has completed.
 	/// </summary>
+	/// <summary>Verifies that a hidden preview fetches nothing, and fetches the item chosen meanwhile once it shows.</summary>
+	[Fact]
+	public void A_hidden_preview_fetches_nothing_until_it_shows()
+	{
+		var provider = new FakePreviewProvider(new PreviewInfo { CssClass = "txt" });
+
+		var component = Render<PDFilePreview>(parameters => parameters
+			.Add(p => p.PreviewProvider, provider)
+			.Add(p => p.IsVisible, false)
+			.Add(p => p.Item, _item));
+		provider.PreviewedPaths.Should().BeEmpty();
+
+		component.Render(parameters => parameters.Add(p => p.IsVisible, true));
+
+		provider.PreviewedPaths.Should().Equal(_item.Path);
+	}
+
 	private sealed class FakePreviewProvider(Task<PreviewInfo> preview) : IPreviewProvider
 	{
 		public FakePreviewProvider(PreviewInfo info)

PanoramicData.Blazor/PDContextMenu.razor.cs

@@ -1,9 +1,15 @@
-namespace PanoramicData.Blazor;
+using PanoramicData.Blazor.Helpers;
+
+namespace PanoramicData.Blazor;
 
 /// <summary>
 /// A Blazor component that displays a context menu when the user right-clicks on the wrapped content.
 /// </summary>
-public partial class PDContextMenu
+/// <remarks>
+/// When the application gives an <see cref="ExceptionHandler"/>, a failure in showing the menu or in an item's click,
+/// such as its script failing, is passed to it instead of ending the Blazor circuit.
+/// </remarks>
+public partial class PDContextMenu : IHandleEvent
 {
 	private static int _idSequence;
 
@@ -43,6 +49,18 @@ public partial class PDContextMenu
 	/// </summary>
 	[Parameter] public bool ShowOnMouseUp { get; set; }
 
+	/// <summary>
+	/// Gets or sets where a failure in one of the menu's events is passed. Without one, a failure is thrown as before.
+	/// </summary>
+	[Parameter] public EventCallback<Exception> ExceptionHandler { get; set; }
+
+	/// <summary>
+	/// Handles an event as <see cref="ComponentBase"/> does, passing a failure to <see cref="ExceptionHandler"/> when
+	/// the application gives one.
+	/// </summary>
+	Task IHandleEvent.HandleEventAsync(EventCallbackWorkItem callback, object? arg)
+		=> ComponentExceptionGuard.HandleEventAsync(callback, arg, ExceptionHandler, StateHasChanged);
+
 	/// <summary>
 	/// Gets the unique identifier of this panel.
 	/// </summary>

PanoramicData.Blazor/PDContextMenu.razor.css

@@ -9,13 +9,15 @@
 	overflow: auto !important;
 }
 
+/* Above what it opens over, such as a sticky table header: Bootstrap's drop-down level, unless the application sets its own */
 .pdcontextmenu {
 	-webkit-user-select: none; /* Chrome/Safari */
 	-moz-user-select: none; /* Firefox */
 	-ms-user-select: none; /* IE10+ */
 	width: fit-content;
 	flex-direction: column;
 	display: none;
+	z-index: var(--pd-contextmenu-z-index, 1000);
 }
 
 .pdcontextmenu.show {

PanoramicData.Blazor/PDContextMenu.razor.js

@@ -20,9 +20,11 @@ export function showMenu(menuId, x, y) {
 				};
 			},
 		};
+		// Fixed, so the menu opens at the pointer wherever it sits: under CSS zoom or a scaled parent, and in a panel that
+		// scrolls or clips. "positionFixed" was popper 1's option, which popper 2 ignores
 		var options = {
 			placement: "bottom-start",
-			positionFixed: true,
+			strategy: "fixed",
 		};
 		menuEl.classList.add("show");
 		popper = window.Popper.createPopper(reference, menuEl, options); // this is popper v2.4.4 syntax

PanoramicData.Blazor/PDFileExplorer.Operations.cs

@@ -30,6 +30,9 @@ private async Task OnTogglePreviewPanelAsync()
 			PreviewPanelVisible = !PreviewPanelVisible;
 
 			await RefreshToolbarAsync();
+
+			// Shown again, the preview fetches the item chosen while it was hidden, also when a host toggles it
+			StateHasChanged();
 		}
 	}
 

PanoramicData.Blazor/PDFileExplorer.razor

@@ -130,6 +130,7 @@
 
 			<PDContextMenu Items="TreeContextItems"
 					   Enabled="ShowContextMenu"
+					   ExceptionHandler="ChildExceptionHandler"
 					   UpdateState="OnTreeContextMenuUpdateStateAsync"
 					   ItemClick="OnTreeContextMenuItemClickAsync">
 
@@ -224,6 +225,7 @@
 
 			<PDContextMenu Items="TableContextItems"
 						   Enabled="ShowContextMenu"
+						   ExceptionHandler="ChildExceptionHandler"
 						   ShowOnMouseUp="true"
 						   UpdateState="OnTableContextMenuUpdateStateAsync"
 						   ItemClick="OnTableContextMenuItemClickAsync">
@@ -424,6 +426,7 @@
 			<PDSplitPanel Size="InitialPreviewSize" MinSize="0">
 
 				<PDFilePreview Item="_previewItem"
+							   IsVisible="PreviewPanelVisible"
 							   ExceptionHandler="ExceptionHandler"
 							   PreviewProvider="PreviewProvider" />