From c289b82cd90d10ea0d3811b6db06176ecef5ebbe Mon Sep 17 00:00:00 2001
From: Jay Hemnani <193022578+jayhemnani9910@users.noreply.github.com>
Date: Sat, 14 Nov 2026 01:47:56 +0530
Subject: [PATCH] Round imported TimeSpan values to milliseconds like dates

TimeSpan.FromDays truncates to whole ticks, so a duration cell of
11 seconds was read as 00:00:10.9999999. DateTime cells already round
to milliseconds through FromOADate.
---
 src/MiniExcel.OpenXml/Styles/OpenXmlStyles.cs          |  2 +-
 .../Main/MiniExcelOpenXmlImporterTests.cs              | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/MiniExcel.OpenXml/Styles/OpenXmlStyles.cs b/src/MiniExcel.OpenXml/Styles/OpenXmlStyles.cs
index 342bb200..28d7c81a 100644
--- a/src/MiniExcel.OpenXml/Styles/OpenXmlStyles.cs
+++ b/src/MiniExcel.OpenXml/Styles/OpenXmlStyles.cs
@@ -192,7 +192,7 @@ internal static async Task<OpenXmlStyles> CreateAsync(OpenXmlZip zip, Cancellati
             return DateTimeHelper.IsValidOADateTime(number) ? DateTime.FromOADate(number) : value;
 
         if (sf.Type == typeof(TimeSpan?))
-            return TimeSpan.FromDays(number);
+            return TimeSpan.FromMilliseconds(Math.Round(number * 86400000d));
 
         return value;
     }
diff --git a/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlImporterTests.cs b/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlImporterTests.cs
index 302a2363..3be2fccf 100644
--- a/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlImporterTests.cs
+++ b/tests/MiniExcel.OpenXml.Tests/Main/MiniExcelOpenXmlImporterTests.cs
@@ -369,6 +369,16 @@ public void TrimColumnNamesTest()
         Assert.Equal(8209.76m, rows[4].Points);
     }
 
+    [Fact]
+    public void TimeSpanKeepsWholeSeconds()
+    {
+        using var path = AutoDeletingPath.Create();
+        MiniExcelV2.Exporters.GetOpenXmlExporter().Export(path.ToString(), new[] { new { Duration = TimeSpan.FromSeconds(11) } });
+
+        var row = _excelImporter.Query(path.ToString(), true).First();
+        Assert.Equal(TimeSpan.FromSeconds(11), (TimeSpan)row.Duration);
+    }
+
     [Fact]
     public void TestDatetimeSpanFormat_ClosedXml()
     {