From c98ea7c81294df27d30d8870602fa4e2a6bdeeb1 Mon Sep 17 00:00:00 2001
From: Michele Bastione <michele.bastione@gmail.com>
Date: Mon, 9 Mar 2026 22:30:20 +0100
Subject: [PATCH 1/2] Adds hidden columns functionality

The new `MiniExcelHiddenAttribute` and property `MiniExcelColumnAttribute.Hidden` now allow for columns to be hidden from Excel's UI when mapped.
---
 README-V2.md                                    | 17 ++++++++++++++++-
 .../Attributes/MiniExcelColumnAttribute.cs      |  1 +
 .../Attributes/MiniExcelHiddenAttribute.cs      |  6 ++++++
 .../Reflection/ColumnMappingsProvider.cs        |  6 ++++--
 .../Reflection/MiniExcelColumnMapping.cs        |  3 ++-
 .../WriteAdapters/DataReaderWriteAdapter.cs     |  2 +-
 src/MiniExcel.OpenXml/Constants/WorksheetXml.cs |  6 +++---
 .../Models/ExcelColumnWidth.cs                  | 10 ++++++----
 src/MiniExcel.OpenXml/OpenXmlWriter.cs          |  6 +++---
 9 files changed, 42 insertions(+), 15 deletions(-)
 create mode 100644 src/MiniExcel.Core/Attributes/MiniExcelHiddenAttribute.cs

diff --git a/README-V2.md b/README-V2.md
index d580431f..4f204255 100644
--- a/README-V2.md
+++ b/README-V2.md
@@ -1209,6 +1209,18 @@ public class Dto
 }
 ```
 
+#### 4. Set Column Visibility
+
+```csharp
+public class Dto
+{
+    public string Name { get; set; }
+
+    [MiniExcelHidden]
+    public int SecretPoints { get; set; }    
+}
+```
+
 #### 4. Multiple column names mapping to the same property.
 
 ```csharp
@@ -1247,11 +1259,14 @@ Multiple attributes can be simplified using the `MiniExcelColumnAttribute`:
 ```csharp
 public class Dto
 {
-    [MiniExcelColumn(Name = "ID",Index =0)]
+    [MiniExcelColumn(Name = "ID", Index = 0)]
     public string MyProperty { get; set; }
     
     [MiniExcelColumn(Name = "CreateDate", Index = 1, Format = "yyyy-MM", Width = 100)]
     public DateTime MyProperty2 { get; set; }
+    
+    [MiniExcelColumn(Name = "SecretColumn", Hidden = true)]
+    public int MyProperty3 { get; set; }
 }
 ```
 
diff --git a/src/MiniExcel.Core/Attributes/MiniExcelColumnAttribute.cs b/src/MiniExcel.Core/Attributes/MiniExcelColumnAttribute.cs
index fe055d6b..a49e964f 100644
--- a/src/MiniExcel.Core/Attributes/MiniExcelColumnAttribute.cs
+++ b/src/MiniExcel.Core/Attributes/MiniExcelColumnAttribute.cs
@@ -8,6 +8,7 @@ public class MiniExcelColumnAttribute : MiniExcelAttributeBase
     public string? Name { get; set; }
     public string[]? Aliases { get; set; } = [];
     public string? Format { get; set; }
+    public bool Hidden { get; set; }
     public bool Ignore { get; set; }
 
     internal int FormatId { get; private set; } = -1;
diff --git a/src/MiniExcel.Core/Attributes/MiniExcelHiddenAttribute.cs b/src/MiniExcel.Core/Attributes/MiniExcelHiddenAttribute.cs
new file mode 100644
index 00000000..15436f12
--- /dev/null
+++ b/src/MiniExcel.Core/Attributes/MiniExcelHiddenAttribute.cs
@@ -0,0 +1,6 @@
+namespace MiniExcelLib.Core.Attributes;
+
+public class MiniExcelHiddenAttribute(bool hidden = true) : MiniExcelAttributeBase
+{
+    public bool Hidden { get; set; } = hidden;
+}
diff --git a/src/MiniExcel.Core/Reflection/ColumnMappingsProvider.cs b/src/MiniExcel.Core/Reflection/ColumnMappingsProvider.cs
index acc2b0b0..1e0d72b5 100644
--- a/src/MiniExcel.Core/Reflection/ColumnMappingsProvider.cs
+++ b/src/MiniExcel.Core/Reflection/ColumnMappingsProvider.cs
@@ -143,6 +143,7 @@ internal static List<MiniExcelColumnMapping> GetMappingsForImport(Type type, str
                 ExcelColumnIndex = m.GetAttribute<MiniExcelColumnIndexAttribute>()?.ExcelColumnIndex ?? excelColumnIndex,
                 ExcelIndexName = m.GetAttribute<MiniExcelColumnIndexAttribute>()?.ExcelXName ?? excelColumn?.IndexName,
                 ExcelColumnWidth = m.GetAttribute<MiniExcelColumnWidthAttribute>()?.ExcelColumnWidth ?? excelColumn?.Width,
+                ExcelHiddenColumn = m.GetAttribute<MiniExcelHiddenAttribute>()?.Hidden ?? excelColumn?.Hidden ?? false,
                 ExcelFormat = excelFormat ?? excelColumn?.Format,
                 ExcelFormatId = excelColumn?.FormatId ?? -1,
                 ExcelColumnType = excelColumn?.Type ?? ColumnType.Value,
@@ -201,9 +202,9 @@ private static void SetDictionaryColumnInfo(List<MiniExcelColumnMapping?> props,
                 if (dynamicColumn.Name is { } colName)
                     mapping.ExcelColumnName = colName;
 
-
                 mapping.ExcelColumnIndex = dynamicColumn.Index;
                 mapping.ExcelColumnWidth = dynamicColumn.Width;
+                mapping.ExcelHiddenColumn = dynamicColumn.Hidden;
                 mapping.ExcelColumnType = dynamicColumn.Type;
                 mapping.CustomFormatter = dynamicColumn.CustomFormatter;
                 
@@ -263,7 +264,8 @@ internal static MiniExcelColumnMapping GetColumnMappingFromDynamicConfiguration(
             return member;
 
         member.Nullable = true;
-        member.ExcelIgnore = dynamicColumn.Ignore;
+        member.ExcelIgnoreColumn = dynamicColumn.Ignore;
+        member.ExcelHiddenColumn = dynamicColumn.Hidden;
         member.ExcelColumnType = dynamicColumn.Type;
         member.ExcelColumnWidth = dynamicColumn.Width;
         member.CustomFormatter = dynamicColumn.CustomFormatter;
diff --git a/src/MiniExcel.Core/Reflection/MiniExcelColumnMapping.cs b/src/MiniExcel.Core/Reflection/MiniExcelColumnMapping.cs
index c406bad9..47e26380 100644
--- a/src/MiniExcel.Core/Reflection/MiniExcelColumnMapping.cs
+++ b/src/MiniExcel.Core/Reflection/MiniExcelColumnMapping.cs
@@ -14,7 +14,8 @@ public class MiniExcelColumnMapping
     public string? ExcelFormat { get; internal set; }
     public double? ExcelColumnWidth { get; internal set; }
     public string? ExcelIndexName { get; internal set; }
-    public bool ExcelIgnore { get; internal set; }
+    public bool ExcelHiddenColumn { get; internal set; }
+    public bool ExcelIgnoreColumn { get; internal set; }
     public int ExcelFormatId { get; internal set; }
     public ColumnType ExcelColumnType { get; internal set; }
     public Func<object?, object?>? CustomFormatter { get; set; }
diff --git a/src/MiniExcel.Core/WriteAdapters/DataReaderWriteAdapter.cs b/src/MiniExcel.Core/WriteAdapters/DataReaderWriteAdapter.cs
index 6e99c376..a4bb8815 100644
--- a/src/MiniExcel.Core/WriteAdapters/DataReaderWriteAdapter.cs
+++ b/src/MiniExcel.Core/WriteAdapters/DataReaderWriteAdapter.cs
@@ -42,7 +42,7 @@ private IEnumerable<CellWriteInfo> GetRowValues(List<MiniExcelColumnMapping> pro
         for (int i = 0; i < _reader.FieldCount; i++)
         {
             var prop = props[i];
-            if (prop is { ExcelIgnore: false })
+            if (prop is { ExcelIgnoreColumn: false })
             {
                 var columnIndex = _configuration.DynamicColumnFirst 
                     ? _reader.GetOrdinal(prop.Key.ToString())
diff --git a/src/MiniExcel.OpenXml/Constants/WorksheetXml.cs b/src/MiniExcel.OpenXml/Constants/WorksheetXml.cs
index 0792dd0d..dd69f623 100644
--- a/src/MiniExcel.OpenXml/Constants/WorksheetXml.cs
+++ b/src/MiniExcel.OpenXml/Constants/WorksheetXml.cs
@@ -42,10 +42,10 @@ internal static string PaneSelection(string pane, string? activeCell, string? sq
     internal const string EndRow = "</x:row>";
     internal const string StartCols = "<x:cols>";
         
-    internal static string Column(int colIndex, double columnWidth)
-        => $"""<x:col min="{colIndex}" max="{colIndex}" width="{columnWidth.ToString(CultureInfo.InvariantCulture)}" customWidth="1" />""";
+    internal static string Column(int colIndex, double columnWidth, bool hidden = false)
+        => $"""<x:col min="{colIndex}" max="{colIndex}" width="{columnWidth.ToString(CultureInfo.InvariantCulture)}" hidden="{(hidden ? 1 : 0)}" customWidth="1" />""";
         
-    private static readonly int MaxColumnLength = Column(int.MaxValue, double.MaxValue).Length;
+    private static readonly int MaxColumnLength = Column(int.MaxValue, double.MaxValue, true).Length;
 
     public static int GetColumnPlaceholderLength(int columnCount) => StartCols.Length + MaxColumnLength * columnCount + EndCols.Length;
 
diff --git a/src/MiniExcel.OpenXml/Models/ExcelColumnWidth.cs b/src/MiniExcel.OpenXml/Models/ExcelColumnWidth.cs
index ad5930f7..d6b652c0 100644
--- a/src/MiniExcel.OpenXml/Models/ExcelColumnWidth.cs
+++ b/src/MiniExcel.OpenXml/Models/ExcelColumnWidth.cs
@@ -1,6 +1,6 @@
 namespace MiniExcelLib.OpenXml.Models;
 
-public sealed class ExcelColumnWidth(int index, double width)
+public sealed class ExcelColumnWidth(int index, double width, bool hidden = false)
 {
     // Aptos is the default font for Office 2023 and onwards, over which the width of cells are calculated at the size of 11pt.
     // Priorly it was Calibri, which had very similar parameters, so no visual differences should be noticed.
@@ -11,6 +11,7 @@ public sealed class ExcelColumnWidth(int index, double width)
 
     public int Index { get; } = index;
     public double Width { get; set; } = width;
+    public bool Hidden { get; set; } = hidden;
 
     public static double GetWidthFromTextLength(double characters)
         => Math.Round(characters + Aptos11Padding, 8);
@@ -37,12 +38,13 @@ internal static ExcelColumnWidthCollection GetFromMappings(ICollection<MiniExcel
 
         foreach (var map in mappings)
         {
-            if (map?.ExcelColumnWidth is not null || minWidth is not null)
+            if (map is { ExcelHiddenColumn: true } or { ExcelColumnWidth: not null } || minWidth is not null)
             {
                 var colIndex = map?.ExcelColumnIndex + 1 ?? i;
-                var width = map?.ExcelColumnWidth ?? minWidth!.Value;
+                var hidden = map?.ExcelHiddenColumn ?? false;
+                var width = map?.ExcelColumnWidth ?? minWidth ?? OpenXmlConfiguration.Default.MinWidth;
 
-                columnWidths.Add(new ExcelColumnWidth(colIndex, width + ExcelColumnWidth.Aptos11Padding));
+                columnWidths.Add(new ExcelColumnWidth(colIndex, width + ExcelColumnWidth.Aptos11Padding, hidden));
             }
 
             i++;
diff --git a/src/MiniExcel.OpenXml/OpenXmlWriter.cs b/src/MiniExcel.OpenXml/OpenXmlWriter.cs
index c846c435..6afa47a8 100644
--- a/src/MiniExcel.OpenXml/OpenXmlWriter.cs
+++ b/src/MiniExcel.OpenXml/OpenXmlWriter.cs
@@ -260,7 +260,7 @@ private async Task<int> WriteValuesAsync(EnhancedStreamWriter writer, object val
             }
 
             int maxRowIndex;
-            var maxColumnIndex = props.Count(x => x is { ExcelIgnore: false });
+            var maxColumnIndex = props.Count(x => x is { ExcelIgnoreColumn: false });
 
             await writer.WriteAsync(WorksheetXml.StartWorksheetWithRelationship, cancellationToken).ConfigureAwait(false);
 
@@ -412,7 +412,7 @@ private static async Task WriteColumnsWidthsAsync(EnhancedStreamWriter writer, I
                 await writer.WriteAsync(WorksheetXml.StartCols, cancellationToken).ConfigureAwait(false);
                 hasWrittenStart = true;
             }
-            await writer.WriteAsync(WorksheetXml.Column(column.Index, column.Width), cancellationToken).ConfigureAwait(false);
+            await writer.WriteAsync(WorksheetXml.Column(column.Index, column.Width, column.Hidden), cancellationToken).ConfigureAwait(false);
         }
 
         if (!hasWrittenStart)
@@ -433,7 +433,7 @@ private async Task PrintHeaderAsync(EnhancedStreamWriter writer, List<MiniExcelC
             //reason : https://github.com/mini-software/MiniExcel/issues/142
             if (p is not null)
             {
-                if (p.ExcelIgnore)
+                if (p.ExcelIgnoreColumn)
                     continue;
 
                 var r = CellReferenceConverter.GetCellFromCoordinates(xIndex, yIndex);

From 19ae7dd85709538749691215e22b9bc62a35014a Mon Sep 17 00:00:00 2001
From: Michele Bastione <michele.bastione@gmail.com>
Date: Mon, 9 Mar 2026 22:39:17 +0100
Subject: [PATCH 2/2] fixed readme bullet points

---
 README-V2.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/README-V2.md b/README-V2.md
index 4f204255..89229e2e 100644
--- a/README-V2.md
+++ b/README-V2.md
@@ -1221,7 +1221,7 @@ public class Dto
 }
 ```
 
-#### 4. Multiple column names mapping to the same property.
+#### 5. Multiple column names mapping to the same property.
 
 ```csharp
 public class Dto
@@ -1233,7 +1233,7 @@ public class Dto
 }
 ```
 
-#### 5. System.ComponentModel.DisplayNameAttribute
+#### 6. System.ComponentModel.DisplayNameAttribute
 
 The `DisplayNameAttribute` has the same effect as the `MiniExcelColumnNameAttribute`:
 
@@ -1252,7 +1252,7 @@ public class Dto
 }
 ```
 
-#### 6. MiniExcelColumnAttribute
+#### 7. MiniExcelColumnAttribute
 
 Multiple attributes can be simplified using the `MiniExcelColumnAttribute`:
 
@@ -1270,7 +1270,7 @@ public class Dto
 }
 ```
 
-#### 7. DynamicColumnAttribute
+#### 8. DynamicColumnAttribute
 
 Attributes can also be set on columns dynamically:
 ```csharp
@@ -1291,7 +1291,7 @@ var exporter = MiniExcel.Exporters.GetOpenXmlExporter();
 exporter.Export(path, value, configuration: config);
 ```
 
-#### 8. MiniExcelSheetAttribute
+#### 9. MiniExcelSheetAttribute
 
 It is possible to define the name and visibility of a sheet through the `MiniExcelSheetAttribute`: