diff --git a/src/MiniExcel/Attributes/ExcelColumnAttribute.cs b/src/MiniExcel/Attributes/ExcelColumnAttribute.cs
index cbcb519e..4dfcd51b 100644
--- a/src/MiniExcel/Attributes/ExcelColumnAttribute.cs
+++ b/src/MiniExcel/Attributes/ExcelColumnAttribute.cs
@@ -58,7 +58,7 @@ public class DynamicExcelColumn : ExcelColumnAttribute
     {
         public string Key { get; set; }
         
-        public Func<object, string> CustomFormatter { get; set; }
+        public Func<object, object> CustomFormatter { get; set; }
 
         public DynamicExcelColumn(string key)
         {
diff --git a/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.Async.cs b/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.Async.cs
index a4823bf2..9790fe5a 100644
--- a/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.Async.cs
+++ b/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.Async.cs
@@ -334,22 +334,11 @@ private async Task WriteCellAsync(MiniExcelAsyncStreamWriter writer, int rowInde
                 return;
             }
 
-            var tuple = GetCellValue(rowIndex, cellIndex, value, p, valueIsNull);
-
-            var styleIndex = tuple.Item1;
-            var dataType = tuple.Item2;
-            var cellValue = tuple.Item3;
-            var columnType = p.ExcelColumnType;
-
-            /*Prefix and suffix blank space will lost after SaveAs #294*/
-            var preserveSpace = cellValue != null && (cellValue.StartsWith(" ", StringComparison.Ordinal) ||
-                                                      cellValue.EndsWith(" ", StringComparison.Ordinal));
-
             if (p.CustomFormatter != null)
             {
                 try
                 {
-                    cellValue = p.CustomFormatter(cellValue);
+                    value = p.CustomFormatter(value);
                 }
                 catch
                 {
@@ -357,6 +346,17 @@ private async Task WriteCellAsync(MiniExcelAsyncStreamWriter writer, int rowInde
                 }
             }
 
+            var tuple = GetCellValue(rowIndex, cellIndex, value, p, valueIsNull);
+
+            var styleIndex = tuple.Item1;
+            var dataType = tuple.Item2;
+            var cellValue = tuple.Item3;
+            var columnType = p.ExcelColumnType;
+
+            /*Prefix and suffix blank space will lost after SaveAs #294*/
+            var preserveSpace = cellValue != null && (cellValue.StartsWith(" ", StringComparison.Ordinal) ||
+                                                      cellValue.EndsWith(" ", StringComparison.Ordinal));
+
             await writer.WriteAsync(WorksheetXml.Cell(columnReference, dataType, GetCellXfId(styleIndex), cellValue, preserveSpace: preserveSpace, columnType: columnType));
             widthCollection?.AdjustWidth(cellIndex, cellValue);
         }
diff --git a/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.cs b/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.cs
index d533e335..96e16955 100644
--- a/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.cs
+++ b/src/MiniExcel/OpenXml/ExcelOpenXmlSheetWriter.cs
@@ -334,17 +334,11 @@ private void WriteCell(MiniExcelStreamWriter writer, int rowIndex, int cellIndex
                 return;
             }
 
-            var tuple = GetCellValue(rowIndex, cellIndex, value, columnInfo, valueIsNull);
-
-            var styleIndex = tuple.Item1; // https://learn.microsoft.com/en-us/dotnet/api/documentformat.openxml.spreadsheet.cell?view=openxml-3.0.1
-            var dataType = tuple.Item2; // https://learn.microsoft.com/en-us/dotnet/api/documentformat.openxml.spreadsheet.cellvalues?view=openxml-3.0.1
-            var cellValue = tuple.Item3;
-
             if (columnInfo?.CustomFormatter != null)
             {
                 try
                 {
-                    cellValue = columnInfo.CustomFormatter(cellValue);
+                    value = columnInfo.CustomFormatter(value);
                 }
                 catch
                 {
@@ -352,6 +346,12 @@ private void WriteCell(MiniExcelStreamWriter writer, int rowIndex, int cellIndex
                 }
             }
 
+            var tuple = GetCellValue(rowIndex, cellIndex, value, columnInfo, valueIsNull);
+
+            var styleIndex = tuple.Item1; // https://learn.microsoft.com/en-us/dotnet/api/documentformat.openxml.spreadsheet.cell?view=openxml-3.0.1
+            var dataType = tuple.Item2; // https://learn.microsoft.com/en-us/dotnet/api/documentformat.openxml.spreadsheet.cellvalues?view=openxml-3.0.1
+            var cellValue = tuple.Item3;
+
             var columnType = columnInfo?.ExcelColumnType ?? ColumnType.Value;
 
             /*Prefix and suffix blank space will lost after SaveAs #294*/
diff --git a/src/MiniExcel/Utils/CustomPropertyHelper.cs b/src/MiniExcel/Utils/CustomPropertyHelper.cs
index 217f3e09..f0cef4a7 100644
--- a/src/MiniExcel/Utils/CustomPropertyHelper.cs
+++ b/src/MiniExcel/Utils/CustomPropertyHelper.cs
@@ -25,7 +25,7 @@ internal class ExcelColumnInfo
         public bool ExcelIgnore { get; internal set; }
         public int ExcelFormatId { get; internal set; }
         public ColumnType ExcelColumnType { get; internal set; }
-        public Func<object, string> CustomFormatter { get; set; }
+        public Func<object, object> CustomFormatter { get; set; }
     }
 
     internal class ExcellSheetInfo
@@ -183,12 +183,9 @@ private static IEnumerable<ExcelColumnInfo> ConvertToExcelCustomPropertyInfo(Pro
                 var excludeNullableType = gt ?? p.PropertyType;
                 var excelFormat = p.GetAttribute<ExcelFormatAttribute>()?.Format;
                 var excelColumn = p.GetAttribute<ExcelColumnAttribute>();
-                if (configuration.DynamicColumns != null && configuration.DynamicColumns.Length > 0)
-                {
-                    var dynamicColumn = configuration.DynamicColumns.SingleOrDefault(_ => _.Key == p.Name);
-                    if (dynamicColumn != null)
-                        excelColumn = dynamicColumn;
-                }
+                var dynamicColumn = configuration?.DynamicColumns?.SingleOrDefault(_ => _.Key == p.Name);
+                if (dynamicColumn != null)
+                    excelColumn = dynamicColumn;
 
                 var ignore = p.GetAttributeValue((ExcelIgnoreAttribute x) => x.ExcelIgnore) || p.GetAttributeValue((ExcelColumnAttribute x) => x.Ignore) || (excelColumn != null && excelColumn.Ignore);
                 if (ignore)
@@ -209,7 +206,8 @@ private static IEnumerable<ExcelColumnInfo> ConvertToExcelCustomPropertyInfo(Pro
                     ExcelColumnWidth = p.GetAttribute<ExcelColumnWidthAttribute>()?.ExcelColumnWidth ?? excelColumn?.Width,
                     ExcelFormat = excelFormat ?? excelColumn?.Format,
                     ExcelFormatId = excelColumn?.FormatId ?? -1,
-                    ExcelColumnType = excelColumn?.Type ?? ColumnType.Value
+                    ExcelColumnType = excelColumn?.Type ?? ColumnType.Value,
+                    CustomFormatter = dynamicColumn?.CustomFormatter
                 };
             }).Where(_ => _ != null);
         }