Handle standalone paragraphs nested in list that must be aligned with other list items #177

Author: onizet

src/Html2OpenXml/Expressions/Numbering/ListExpression.cs

@@ -90,17 +90,38 @@ public override IEnumerable<OpenXmlElement> Interpret(ParsingContext context)
             var expression = new BlockElementExpression(liNode);
             var childElements = expression.Interpret(context);
             if (!childElements.Any()) continue;
-            Paragraph p = (Paragraph) childElements.First();
-
-            p.ParagraphProperties ??= new();
-            p.ParagraphProperties.ParagraphStyleId = GetStyleIdForListItem(context.DocumentStyle, liNode);
-            p.ParagraphProperties.NumberingProperties = new NumberingProperties {
-                NumberingLevelReference = new() { Val = level - 1 },
-                NumberingId = new() { Val = listContext.InstanceId }
-            };
-            if (listContext.Dir.HasValue) {
-                p.ParagraphProperties.BiDi = new() {
-                    Val = OnOffValue.FromBoolean(listContext.Dir == DirectionMode.Rtl)
+
+            // ensure to filter out any non-paragraph like any nested table
+            var paragraphs = childElements.OfType<Paragraph>();
+            var listItemStyleId = GetStyleIdForListItem(context.DocumentStyle, liNode);
+
+            if (paragraphs.Any())
+            {
+                var p = paragraphs.First();
+                p.ParagraphProperties ??= new();
+                p.ParagraphProperties.ParagraphStyleId = listItemStyleId;
+                p.ParagraphProperties!.NumberingProperties ??= new NumberingProperties {
+                    NumberingLevelReference = new() { Val = level - 1 },
+                    NumberingId = new() { Val = listContext.InstanceId }
+                };
+                if (listContext.Dir.HasValue) {
+                    p.ParagraphProperties.BiDi = new() {
+                        Val = OnOffValue.FromBoolean(listContext.Dir == DirectionMode.Rtl)
+                    };
+                }
+            }
+
+            // any standalone paragraphs must be aligned (indented) along its current level
+            foreach (var p in paragraphs.Skip(1))
+            {
+                // if this is a list item paragraph, skip it
+                if (p.ParagraphProperties?.NumberingProperties is not null)
+                    continue;
+
+                p.ParagraphProperties ??= new();
+                p.ParagraphProperties.ParagraphStyleId ??= (ParagraphStyleId?) listItemStyleId!.CloneNode(true);
+                p.ParagraphProperties.Indentation = new() {
+                    Left = (level * Indentation * 2).ToString()
                 };
             }
 

test/HtmlToOpenXml.Tests/NumberingTests.cs

@@ -581,5 +581,35 @@ await converter.ParseBody(@"<ol>
             });
             AssertThatOpenXmlDocumentIsValid();
         }
+
+        [Test]
+        public void NestedParagraph_ReturnsIndentedItems()
+        {
+            var elements = converter.Parse(@"<ul>
+                <li>
+                    <p>Paragraph text</p>
+                    <p>Paragraph text</p>
+                </li>
+                </ul>");
+
+            Assert.That(elements, Is.Not.Empty);
+
+            var inst = mainPart.NumberingDefinitionsPart?.Numbering
+                .Elements<NumberingInstance>()
+                .SingleOrDefault();
+            Assert.That(inst, Is.Not.Null);
+            Assert.Multiple(() => {
+                Assert.That(elements.Last().GetFirstChild<ParagraphProperties>()?.NumberingProperties?.NumberingId,
+                    Is.Null,
+                    "Last paragraph is standalone and not linked to a list instance");
+                Assert.That(elements.Cast<Paragraph>().Select(e => 
+                    e.ParagraphProperties?.ParagraphStyleId?.Val?.Value),
+                    Has.All.EqualTo("ListParagraph"),
+                    "All paragraphs use the same paragraph style");
+                Assert.That(elements.Last().GetFirstChild<ParagraphProperties>()?.Indentation?.Left?.Value,
+                    Is.EqualTo("720"),
+                    "Last standalone paragraph is aligned with the level 1");
+            });
+        }
     }
 }