update：作业列表导出报错

VOL.Core/Utilities/Tool.cs

@@ -89,7 +89,10 @@ namespace VOL.Core.Utilities
             }
         }
 
-        public static byte[] ExportToExcel<T>(Dictionary<string, List<T>> sheetDataList, List<string> fields)
+        public static byte[] ExportToExcel<T>(
+            Dictionary<string, List<T>> sheetDataList,
+            List<string> fields,
+            bool autoFitColumns = true)
         {
             using (var package = new ExcelPackage(new FileInfo("filename.xlsx")))
             {
@@ -101,7 +104,7 @@ namespace VOL.Core.Utilities
                     var sheetName = sheet.Key;
 
                     var worksheet = package.Workbook.Worksheets.Add(sheetName);
-                    ConfigureWorksheet<T>(worksheet, sheetData, fields);
+                    ConfigureWorksheet(worksheet, sheetData, fields, autoFitColumns);
                 }
 
                 return package.GetAsByteArray();
@@ -301,7 +304,11 @@ namespace VOL.Core.Utilities
         /// <param name="worksheet"></param>
         /// <param name="sheetData"></param>
         /// <param name="fields"></param>
-        private static void ConfigureWorksheet<T>(ExcelWorksheet worksheet, IEnumerable<T> sheetData, List<string> fields)
+        private static void ConfigureWorksheet<T>(
+            ExcelWorksheet worksheet,
+            IEnumerable<T> sheetData,
+            List<string> fields,
+            bool autoFitColumns)
         {
             // 添加表头
             for (int i = 0; i < fields.Count; i++)
@@ -335,8 +342,37 @@ namespace VOL.Core.Utilities
                 }
             }
 
-            // 自动调整列宽
+            if (autoFitColumns)
+            {
                 worksheet.Cells.AutoFitColumns();
+                return;
+            }
+
+            SetColumnWidthsWithoutGdi(worksheet, fields.Count);
+        }
+
+        private static void SetColumnWidthsWithoutGdi(ExcelWorksheet worksheet, int columnCount)
+        {
+            const double minWidth = 10;
+            const double maxWidth = 40;
+
+            for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++)
+            {
+                var maxContentWidth = worksheet.Cells
+                    .Where(cell => cell.Start.Column == columnIndex)
+                    .Select(cell => GetExcelContentWidth(cell.Value))
+                    .DefaultIfEmpty((int)minWidth)
+                    .Max();
+
+                worksheet.Column(columnIndex).Width =
+                    Math.Min(maxWidth, Math.Max(minWidth, maxContentWidth + 2));
+            }
+        }
+
+        private static int GetExcelContentWidth(object value)
+        {
+            var text = value?.ToString() ?? string.Empty;
+            return text.Sum(character => character > 255 ? 2 : 1);
         }
         private static string GetDisplayName<T>(string propertyName)
         {

VOL.WebApi/Controllers/Business/HomeWorkController.cs

@@ -77,7 +77,7 @@ namespace VOL.WebApi.Controllers.Business
                 nameof(HomeWorkStudentExportModel.Result)
             };
 
-            var excelBytes = Tool.ExportToExcel(sheets, columns);
+            var excelBytes = Tool.ExportToExcel(sheets, columns, autoFitColumns: false);
             var fileName = $"作业学生明细{DateTime.Now:yyyyMMddHHmmss}.xlsx";
             return File(
                 excelBytes,