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fix: fix template export generating corrupted Excel files #917

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7eb1196
fix: fix template export generating corrupted Excel files
A-nony-mous Jan 23, 2026
aeb5f0e
fix: handle inline string cells and preserve namespace prefixes in Ex…
A-nony-mous Jan 25, 2026
58c35de
fix: ensure text is not null when processing XML nodes in Excel export
A-nony-mous Jan 25, 2026
e9c1251
fix: update template to use inlineStr format for string cells in Exce…
A-nony-mous Jan 25, 2026
24eb49a
Couple of fixes
michelebastione Jan 25, 2026
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187 changes: 158 additions & 29 deletions src/MiniExcel.Core/OpenXml/Templates/OpenXmlTemplate.Impl.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -138,10 +138,13 @@ internal partial class OpenXmlTemplate
private static readonly Regex TemplateRegex = TemplateRegexImpl();
[GeneratedRegex(@".*?\{\{.*?\}\}.*?")] private static partial Regex NonTemplateRegexImpl();
private static readonly Regex NonTemplateRegex = NonTemplateRegexImpl();
[GeneratedRegex(@"<(?:x:)?v>\s*</(?:x:)?v>")] private static partial Regex EmptyVTagRegexImpl();
private static readonly Regex EmptyVTagRegex = EmptyVTagRegexImpl();
#else
private static readonly Regex CellRegex = new("([A-Z]+)([0-9]+)", RegexOptions.Compiled);
private static readonly Regex TemplateRegex = new(@"\{\{(.*?)\}\}", RegexOptions.Compiled);
private static readonly Regex NonTemplateRegex = new(@".*?\{\{.*?\}\}.*?", RegexOptions.Compiled);
private static readonly Regex EmptyVTagRegex = new(@"<(?:x:)?v>\s*</(?:x:)?v>", RegexOptions.Compiled);
#endif

[CreateSyncVersion]
Expand Down Expand Up @@ -299,6 +302,15 @@ private async Task WriteSheetXmlAsync(Stream outputFileStream, XmlDocument doc,
phoneticPr.ParentNode.RemoveChild(phoneticPr);
}

// Extract autoFilter - must be written before mergeCells and phoneticPr per ECMA-376
var autoFilter = doc.SelectSingleNode("/x:worksheet/x:autoFilter", Ns);
var autoFilterXml = string.Empty;
if (autoFilter is not null)
{
autoFilterXml = autoFilter.OuterXml;
autoFilter.ParentNode.RemoveChild(autoFilter);
}

var contents = doc.InnerXml.Split(new[] { $"<{prefix}sheetData>{{{{{{{{{{{{split}}}}}}}}}}}}</{prefix}sheetData>" }, StringSplitOptions.None);

using var writer = new StreamWriter(outputFileStream, Encoding.UTF8);
Expand Down Expand Up @@ -524,11 +536,24 @@ await writer.WriteAsync($"</{prefix}sheetData>"
#endif
).ConfigureAwait(false);

// ECMA-376 element order: sheetData → autoFilter → mergeCells → phoneticPr → conditionalFormatting

// 1. autoFilter (must come before mergeCells)
if (!string.IsNullOrEmpty(autoFilterXml))
{
await writer.WriteAsync(CleanXml(autoFilterXml, endPrefix)
#if NET7_0_OR_GREATER
.AsMemory(), cancellationToken
#endif
).ConfigureAwait(false);
}

// 2. mergeCells
if (_newXMergeCellInfos.Count != 0)
{
await writer.WriteAsync($"<{prefix}mergeCells count=\"{_newXMergeCellInfos.Count}\">"
#if NET7_0_OR_GREATER
.AsMemory(), cancellationToken
.AsMemory(), cancellationToken
#endif
).ConfigureAwait(false);
foreach (var cell in _newXMergeCellInfos)
Expand All @@ -541,25 +566,27 @@ await writer.WriteAsync(cell.ToXmlString(prefix)
}
await writer.WriteLineAsync($"</{prefix}mergeCells>"
#if NET7_0_OR_GREATER
.AsMemory(), cancellationToken
.AsMemory(), cancellationToken
#endif
).ConfigureAwait(false);
}

// 3. phoneticPr
if (!string.IsNullOrEmpty(phoneticPrXml))
{
await writer.WriteAsync(phoneticPrXml
await writer.WriteAsync(CleanXml(phoneticPrXml, endPrefix)
#if NET7_0_OR_GREATER
.AsMemory(), cancellationToken
.AsMemory(), cancellationToken
#endif
).ConfigureAwait(false);
}

// 4. conditionalFormatting
if (newConditionalFormatRanges.Count != 0)
{
await writer.WriteAsync(string.Join(string.Empty, newConditionalFormatRanges.Select(cf => cf.Node.OuterXml))
await writer.WriteAsync(CleanXml(string.Join(string.Empty, newConditionalFormatRanges.Select(cf => cf.Node.OuterXml)), endPrefix)
#if NET7_0_OR_GREATER
.AsMemory(), cancellationToken
.AsMemory(), cancellationToken
#endif
).ConfigureAwait(false);
}
Expand Down Expand Up @@ -601,9 +628,20 @@ private async Task<GenerateCellValuesContext> GenerateCellValuesAsync(GenerateCe
var notFirstRowElement = rowElement.Clone();
foreach (XmlElement c in notFirstRowElement.SelectNodes("x:c", Ns))
{
var v = c.SelectSingleNode("x:v", Ns);
if (v is not null && !NonTemplateRegex.IsMatch(v.InnerText))
v.InnerText = string.Empty;
// Try <v> first (for t="n"/t="b" cells), then <is><t> (for t="inlineStr" cells)
var vTag = c.SelectSingleNode("x:v", Ns);
if (vTag is not null)
{
if (!NonTemplateRegex.IsMatch(vTag.InnerText))
vTag.InnerText = string.Empty;
}
else
{
// Handle inline string cells
var t = c.SelectSingleNode("x:is/x:t", Ns);
if (t is not null && !NonTemplateRegex.IsMatch(t.InnerText))
t.InnerText = string.Empty;
}
}

foreach (var item in rowInfo.CellIEnumerableValues)
Expand Down Expand Up @@ -695,7 +733,7 @@ private async Task<GenerateCellValuesContext> GenerateCellValuesAsync(GenerateCe
{
var replacements = new Dictionary<string, string>();
#if NETCOREAPP3_0_OR_GREATER
string MatchDelegate(Match x) => CollectionExtensions.GetValueOrDefault(replacements, x.Groups[1].Value, "");
string MatchDelegate(Match x) => CollectionExtensions.GetValueOrDefault(replacements, x.Groups[1].Value, "");
#else
string MatchDelegate(Match x) => replacements.TryGetValue(x.Groups[1].Value, out var repl) ? repl : "";
#endif
Expand Down Expand Up @@ -762,6 +800,9 @@ private async Task<GenerateCellValuesContext> GenerateCellValuesAsync(GenerateCe

substXmlRow = rowXml.ToString();
substXmlRow = TemplateRegex.Replace(substXmlRow, MatchDelegate);

// Cleanup empty <v> tags which defaults to invalid XML
substXmlRow = EmptyVTagRegex.Replace(substXmlRow, "");
}

rowXml.Clear();
Expand Down Expand Up @@ -794,9 +835,13 @@ private async Task<GenerateCellValuesContext> GenerateCellValuesAsync(GenerateCe
var mergeBaseRowIndex = newRowIndex;
newRowIndex += rowInfo.IEnumerableMercell?.Height ?? 1;

// Replace {{$rowindex}} in the already-built substXmlRow
rowXml.Replace("{{$rowindex}}", mergeBaseRowIndex.ToString());

// replace formulas
ProcessFormulas(rowXml, newRowIndex);
await writer.WriteAsync(CleanXml(rowXml, endPrefix).ToString()
var finalXml = CleanXml(rowXml, endPrefix).ToString();
await writer.WriteAsync(finalXml
#if NET7_0_OR_GREATER
.AsMemory(), cancellationToken
#endif
Expand Down Expand Up @@ -1040,7 +1085,8 @@ private void ProcessFormulas(StringBuilder rowXml, int rowIndex)
private static string CleanXml(string xml, string endPrefix) => CleanXml(new StringBuilder(xml), endPrefix).ToString();
private static StringBuilder CleanXml(StringBuilder xml, string endPrefix) => xml
.Replace("xmlns:x14ac=\"http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac\"", "")
.Replace($"xmlns{endPrefix}=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\"", "");
.Replace($"xmlns{endPrefix}=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\"", "")
.Replace("xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\"", "");

private static void ReplaceSharedStringsToStr(IDictionary<int, string> sharedStrings, XmlNodeList rows)
{
Expand All @@ -1061,10 +1107,86 @@ private static void ReplaceSharedStringsToStr(IDictionary<int, string> sharedStr
if (sharedStrings is null || !sharedStrings.TryGetValue(int.Parse(v.InnerText), out var shared))
continue;

// change type = str and replace its value
//TODO: remove sharedstring?
v.InnerText = shared;
c.SetAttribute("t", "str");
// change type = inlineStr and replace its value
// Use the same prefix as the source element to handle namespaced documents (e.g., x:v -> x:is, x:t)
var prefix = v.Prefix;
c.RemoveChild(v);
var isNode = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("is", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "is", Schemas.SpreadsheetmlXmlns);
var tNode = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("t", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "t", Schemas.SpreadsheetmlXmlns);
tNode.InnerText = shared;
isNode.AppendChild(tNode);
c.AppendChild(isNode);

c.RemoveAttribute("t");
c.SetAttribute("t", "inlineStr");
}
}
}

private static void SetCellType(XmlElement c, string type)
{
if (type == "str") type = "inlineStr"; // Force inlineStr for strings

// Determine the prefix used in this document (e.g., "x" for x:c, x:v, etc.)
var prefix = c.Prefix;

if (type == "inlineStr")
{
// Ensure <is><t>...</t></is>
c.SetAttribute("t", "inlineStr");
var v = c.SelectSingleNode("x:v", Ns);
if (v != null)
{
var text = v.InnerText;
c.RemoveChild(v);
var isNode = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("is", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "is", Schemas.SpreadsheetmlXmlns);
var tNode = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("t", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "t", Schemas.SpreadsheetmlXmlns);
tNode.InnerText = text;
isNode.AppendChild(tNode);
c.AppendChild(isNode);
}
else if (c.SelectSingleNode("x:is", Ns) == null)
{
// Create empty <is><t></t></is> if neither <v> nor <is> exists
var isNode = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("is", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "is", Schemas.SpreadsheetmlXmlns);
var tNode = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("t", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "t", Schemas.SpreadsheetmlXmlns);
isNode.AppendChild(tNode);
c.AppendChild(isNode);
}
}
else
{
// Ensure <v>...</v>
// For numbers/booleans, we remove 't' attribute to let it be default (number)
// or we could set it to 'n' explicitly, but removing is safer for general number types
if (type == "b")
c.SetAttribute("t", "b");
else
c.RemoveAttribute("t");

var isNode = c.SelectSingleNode("x:is", Ns);
if (isNode != null)
{
var tNode = isNode.SelectSingleNode("x:t", Ns);
var text = tNode?.InnerText ?? string.Empty;
c.RemoveChild(isNode);
var v = string.IsNullOrEmpty(prefix)
? c.OwnerDocument.CreateElement("v", Schemas.SpreadsheetmlXmlns)
: c.OwnerDocument.CreateElement(prefix, "v", Schemas.SpreadsheetmlXmlns);
v.InnerText = text;
c.AppendChild(v);
}
}
}
Expand Down Expand Up @@ -1117,7 +1239,7 @@ private void UpdateDimensionAndGetRowsInfo(IDictionary<string, object?> inputMap
c.SetAttribute("r", $"{StringHelper.GetLetters(r)}{{{{$rowindex}}}}");
}

var v = c.SelectSingleNode("x:v", Ns);
var v = c.SelectSingleNode("x:v", Ns) ?? c.SelectSingleNode("x:is/x:t", Ns);
if (v?.InnerText is null)
continue;

Expand Down Expand Up @@ -1240,19 +1362,19 @@ private void UpdateDimensionAndGetRowsInfo(IDictionary<string, object?> inputMap

if (isMultiMatch)
{
c.SetAttribute("t", "str");
SetCellType(c, "str");
}
else if (TypeHelper.IsNumericType(type) && !type.IsEnum)
{
c.SetAttribute("t", "n");
SetCellType(c, "n");
}
else if (Type.GetTypeCode(type) == TypeCode.Boolean)
{
c.SetAttribute("t", "b");
SetCellType(c, "b");
}
else if (Type.GetTypeCode(type) == TypeCode.DateTime)
{
c.SetAttribute("t", "str");
SetCellType(c, "str");
}

break;
Expand Down Expand Up @@ -1292,36 +1414,36 @@ private void UpdateDimensionAndGetRowsInfo(IDictionary<string, object?> inputMap

if (isMultiMatch)
{
c.SetAttribute("t", "str");
SetCellType(c, "str");
}
else if (TypeHelper.IsNumericType(type) && !type.IsEnum)
{
c.SetAttribute("t", "n");
SetCellType(c, "n");
}
else if (Type.GetTypeCode(type) == TypeCode.Boolean)
{
c.SetAttribute("t", "b");
SetCellType(c, "b");
}
else if (Type.GetTypeCode(type) == TypeCode.DateTime)
{
c.SetAttribute("t", "str");
SetCellType(c, "str");
}
}
else
{
var cellValueStr = cellValue?.ToString(); // value did encodexml, so don't duplicate encode value (https://gitee.com/dotnetchina/MiniExcel/issues/I4DQUN)
if (isMultiMatch || cellValue is string) // if matchs count over 1 need to set type=str (https://user-images.githubusercontent.com/12729184/114530109-39d46d00-9c7d-11eb-8f6b-52ad8600aca3.png)
{
c.SetAttribute("t", "str");
SetCellType(c, "str");
}
else if (decimal.TryParse(cellValueStr, out var outV))
{
c.SetAttribute("t", "n");
SetCellType(c, "n");
cellValueStr = outV.ToString(CultureInfo.InvariantCulture);
}
else if (cellValue is bool b)
{
c.SetAttribute("t", "b");
SetCellType(c, "b");
cellValueStr = b ? "1" : "0";
}
else if (cellValue is DateTime timestamp)
Expand All @@ -1330,6 +1452,13 @@ private void UpdateDimensionAndGetRowsInfo(IDictionary<string, object?> inputMap
cellValueStr = timestamp.ToString("yyyy-MM-dd HH:mm:ss");
}

if (string.IsNullOrEmpty(cellValueStr) && string.IsNullOrEmpty(c.GetAttribute("t")))
{
SetCellType(c, "str");
}

// Re-acquire v after SetCellType may have changed DOM structure
v = c.SelectSingleNode("x:v", Ns) ?? c.SelectSingleNode("x:is/x:t", Ns);
v.InnerText = v.InnerText.Replace($"{{{{{propNames[0]}}}}}", cellValueStr); //TODO: auto check type and set value
}
}
Expand Down Expand Up @@ -1396,4 +1525,4 @@ private static bool EvaluateStatement(object tagValue, string comparisonOperator
_ => false
};
}
}
}
5 changes: 3 additions & 2 deletions tests/MiniExcel.Core.Tests/MiniExcelIssueTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1042,8 +1042,9 @@ public void TestIssueI4DQUN()
_excelTemplater.ApplyTemplate(path.ToString(), templatePath, value);

var sheetXml = SheetHelper.GetZipFileContent(path.ToString(), "xl/worksheets/sheet1.xml");
Assert.Contains("<v>Hello &amp; World &lt; , &gt; , \" , '</v>", sheetXml);
Assert.Contains("<v>Hello &amp; Value &lt; , &gt; , \" , '</v>", sheetXml);
// Template now uses inlineStr format (<is><t>...</t></is>) instead of SharedStrings (<v>...</v>)
Assert.Contains("<t>Hello &amp; World &lt; , &gt; , \" , '</t>", sheetXml);
Assert.Contains("<t>Hello &amp; Value &lt; , &gt; , \" , '</t>", sheetXml);
}

/// <summary>
Expand Down
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