20220313 3张表格 导出excel功能

20220313_Excel/TempTask.WebEntry/Tools/ExcelHelper.cs

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+using NPOI.HSSF.UserModel;
+using NPOI.SS.UserModel;
+using NPOI.XSSF.UserModel;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace TempTask.WebEntry.Tools
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public static class ExcelHelper
+    {
+        static ExcelHelper()
+        {
+            System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
+        }
+        /// <summary>
+        /// 判断是否为兼容模式
+        /// </summary>
+        /// <param name="filePath"></param>
+        /// <returns></returns>
+        public static bool GetIsCompatible(string filePath)
+        {
+            return filePath.EndsWith(".xls", StringComparison.OrdinalIgnoreCase);
+        }
+        /// <summary>
+        /// 创建工作薄
+        /// </summary>
+        /// <param name="isCompatible"></param>
+        /// <returns></returns>
+        public static IWorkbook CreateWorkbook(bool isCompatible)
+        {
+            if (isCompatible)
+            {
+                return new HSSFWorkbook();
+            }
+            else
+            {
+                return new XSSFWorkbook();
+            }
+        }
+
+        /// <summary>
+        /// 创建工作薄(依据文件流)
+        /// </summary>
+        /// <param name="isCompatible"></param>
+        /// <param name="stream"></param>
+        /// <returns></returns>
+        public static IWorkbook CreateWorkbook(bool isCompatible, dynamic stream)
+        {
+            if (isCompatible)
+            {
+                return new HSSFWorkbook(stream);
+            }
+            else
+            {
+                return new XSSFWorkbook(stream);
+            }
+        }
+
+
+
+        /// <summary>
+        /// 列名字母转索引
+        /// </summary>
+        /// <param name="columnName"></param>
+        /// <returns></returns>
+        public static int ToExcelColumnIndex(this string columnName)
+        {
+            if (!Regex.IsMatch(columnName.ToUpper(), @"[A-Z]+")) { throw new Exception("invalid parameter"); }
+            int index = 0;
+            char[] chars = columnName.ToUpper().ToCharArray();
+            for (int i = 0; i < chars.Length; i++)
+            {
+                index += ((int)chars[i] - (int)'A' + 1) * (int)Math.Pow(26, chars.Length - i - 1);
+            }
+            return index - 1;
+        }
+        /// <summary>
+        /// 列索引转字母
+        /// </summary>
+        /// <param name="index"></param>
+        /// <returns></returns>
+        public static string ToExcelColumnName(this int index)
+        {
+            if (index < 0) { throw new Exception("invalid parameter"); }
+            List<string> chars = new List<string>();
+            do
+            {
+                if (chars.Count > 0) index--;
+                chars.Insert(0, ((char)(index % 26 + (int)'A')).ToString());
+                index = (int)((index - index % 26) / 26);
+            } while (index > 0);
+            return String.Join(string.Empty, chars.ToArray());
+        }
+    }
+}