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Fixed rounding error of datetime #2559

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Merged
JanKallman merged 2 commits into from
Oct 2, 2026
Merged

Fixed rounding error of datetime #2559

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528d0ed
Fixed rounding error of datetime
OssianEPPlus Oct 1, 2026
456259a
Fixed for datetimes before 1899
OssianEPPlus Oct 2, 2026
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15 changes: 13 additions & 2 deletions src/EPPlus/Utils/TypeConversion/ConvertUtil.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -543,6 +543,17 @@ private static bool Matches(char c, ref int ix)
}
}

private static TimeSpan GetTimespanTicks(DateTime dt)
{
var startDate = DateTime.FromOADate(0);
long ticks = dt.Ticks;
if(dt.Ticks > startDate.Date.Ticks)
{
ticks = dt.Ticks - startDate.Ticks;
}
return new TimeSpan(ticks);
}

/// <summary>
/// Convert cell value to desired type, including nullable structs.
/// When converting blank string to nullable struct (e.g. ' ' to int?) null is returned.
Expand Down Expand Up @@ -621,7 +632,7 @@ internal static T GetTypedCellValueInner<T>(object value, bool returnDefaultIfEx
TimeSpan? ts = null;
if (value is DateTime dt)
{
ts = new TimeSpan((long)(dt.ToOADate() * TimeSpan.TicksPerDay));
ts = GetTimespanTicks(dt);
}
#if (NET8_0_OR_GREATER)
else if (value is TimeOnly timeOnly)
Expand All @@ -630,7 +641,7 @@ internal static T GetTypedCellValueInner<T>(object value, bool returnDefaultIfEx
}
else if (value is DateOnly dateOnly)
{
ts=new TimeSpan((long)dateOnly.ToDateTime(TimeOnly.MinValue).ToOADate() * TimeSpan.TicksPerDay);
ts = GetTimespanTicks(dateOnly.ToDateTime(TimeOnly.MinValue));
}
#endif
else if (conversion.TryGetTimeSpan(out object tso))
Expand Down
37 changes: 37 additions & 0 deletions src/EPPlusTest/Core/Range/RangeTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ Date Author Change
using OfficeOpenXml;
using OfficeOpenXml.FormulaParsing.Excel.Functions.MathFunctions;
using OfficeOpenXml.Style;
using OfficeOpenXml.Utils.TypeConversion;
using System;
using System.Collections.Generic;
using System.Diagnostics;
Expand Down Expand Up @@ -374,6 +375,42 @@ public void RangeIsEmptyStyleTests()
Assert.IsTrue(isEmpty);
}

[TestMethod]
public void i2558()
{
using(var p = OpenTemplatePackage("TestTime.xlsx"))
{
var worksheet = p.Workbook.Worksheets.First();
var cell = worksheet.Cells[1, 1];

var rawValue = cell.Value;
var valueAsString = cell.GetValue<string>();
var valueAsTimeSpan = cell.GetValue<TimeSpan>();

Console.WriteLine($"Raw value : {cell.Value}");
Console.WriteLine($"Raw type : {cell.Value?.GetType()}");
Console.WriteLine($"Number format : {cell.Style.Numberformat.Format}");

var time = cell.GetValue<TimeSpan>();

Console.WriteLine($"TimeSpan : {time:c}");
Console.WriteLine($"Hours : {time.Hours}");
Console.WriteLine($"Minutes : {time.Minutes}");
Console.WriteLine($"Seconds : {time.Seconds}");
Console.WriteLine($"Ticks : {time.Ticks}");

var expected = new TimeSpan(6, 10, 0);
var matches =
valueAsTimeSpan.Hours == expected.Hours &&
valueAsTimeSpan.Minutes == expected.Minutes &&
valueAsTimeSpan.Seconds == expected.Seconds;

Assert.AreEqual(expected, valueAsTimeSpan);
//Console.WriteLine($"Actual : {valueAsTimeSpan:hh\\:mm\\:ss}");
//Console.WriteLine($"Expected : {expected:hh\\:mm\\:ss}");
//Console.WriteLine(matches ? "PASS" : "FAIL");
}
}

#if NET6_0_OR_GREATER
[TestMethod]
Expand Down
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