[Stack] Added 'Stretch' horizontal alignment option (#2800)

* Added missing 'Stretch' horizontal alignment option to FluentStack

Introduced a new horizontal alignment option, `Stretch`, to the `FluentStack` component. Updated the `HorizontalAlignment` enum in `HorizontalAlignment.cs` to include the `Stretch` value with a summary comment. Modified the `GetHorizontalAlignment` method in `FluentStack.razor.cs` to map `HorizontalAlignment.Stretch`  to the string "stretch".

* Add validation to Alignment property in DialogParameters

The Alignment property now includes a custom setter that throws an ArgumentException if set to HorizontalAlignment.Stretch, ensuring this value is not supported.

* Moved "_alignment" variable declaration to top of DialogParameters class

* Added a note re. stretch to the XML documentation for the `Alignment` property

* Added unit test for DialogParameters invalid Aligment value

---------

Co-authored-by: Vincent Baaij <[email protected]>
Co-authored-by: Denis Voituron <[email protected]>

src/Core/Components/Dialog/Parameters/DialogParameters.cs

@@ -4,15 +4,32 @@ namespace Microsoft.FluentUI.AspNetCore.Components;
 
 public class DialogParameters : ComponentParameters, IDialogParameters
 {
+    private HorizontalAlignment _alignment = HorizontalAlignment.Center;
+
     public string Id { get; set; } = Identifier.NewId();
 
     /// <summary>
     /// Gets or sets the dialog position:
     /// left (full height), right (full height)
     /// or screen middle (using Width and Height properties).
-    /// </summary>
-    public virtual HorizontalAlignment Alignment { get; set; } = HorizontalAlignment.Center;
-
+    /// HorizontalAlignment.Stretch is not supported for this property.
+    /// </summary>
+    public virtual HorizontalAlignment Alignment
+    {
+        set
+        {
+            if (value == HorizontalAlignment.Stretch)
+            {
+                throw new ArgumentException("Alignment HorizontalAlignment.Stretch is not supported for DialogParameters");
+            }
+            _alignment = value;
+        }
+        get
+        {
+            return _alignment;
+        }
+    }
+
     /// <summary>
     /// Gets or sets the title of the dialog.
     /// </summary>

src/Core/Components/Stack/FluentStack.razor.cs

@@ -86,6 +86,7 @@ private string GetHorizontalAlignment()
             HorizontalAlignment.Center => "center",
             HorizontalAlignment.Right => "end",
             HorizontalAlignment.End => "end",
+            HorizontalAlignment.Stretch => "stretch",
             _ => "start",
         };
     }

src/Core/Enums/HorizontalAlignement.cs

@@ -29,4 +29,9 @@ public enum HorizontalAlignment
     /// The content is aligned to the end.
     /// </summary>
     End,
+
+    /// <summary>
+    /// The content is stretched to fill the available space.
+    /// </summary>
+    Stretch,
 }

tests/Core/Dialog/FluentDialogServiceTests.razor

@@ -1,4 +1,5 @@
 @using Xunit;
+@using HorizontalAlignment = Microsoft.FluentUI.AspNetCore.Components.HorizontalAlignment
 @inherits TestContext
 @code
 {
@@ -115,6 +116,27 @@
         Assert.Equal("Oh yes", cut.Find("fluent-button[appearance='accent']").InnerHtml);
     }
 
+    [Fact]
+    public async Task FluentDialogService_AlignmentInvalid()
+    {
+        Services.AddFluentUIComponents();
+
+        // Arrange
+        var cut = Render(@<FluentDialogProvider/>   );
+        var dialogService = Services.GetRequiredService<IDialogService>();
+
+        // Act/Assert
+        var exception = await Assert.ThrowsAsync<ArgumentException>(async () =>
+        {
+            var dialog = await dialogService.ShowDialogAsync<TestDialogHeaderFooter>(new DialogParameters()
+            {
+                Alignment = HorizontalAlignment.Stretch, // Stretch is not supported
+            });
+        });
+
+        Assert.Equal("Alignment HorizontalAlignment.Stretch is not supported for DialogParameters", exception.Message);
+    }
+
     private class UpdateDialogUser
     {
         public int Id { get; set; } = 0;