NPOI操作EXCEL

using System; using System.Data; using System.Diagnostics; using System.Windows.Forms;  namespace npoi1 {     public partial class mainForm : Form     {         public mainForm()         {             InitializeComponent();         }          private void Form1_Load(object sender, EventArgs e)         {          }          private void button1_Click(object sender, EventArgs e)         {             Stopwatch sw = new Stopwatch();             sw.Start();             //dataGridView1.DataSource = NPOIExcel.ExcelToDataTable("电脑统计表.xlsx", true);//方式1             dataGridView1.DataSource = NPOIExcel.ExcelToTable("电脑统计表.xlsx");//方式2             sw.Stop();             label1.Text = sw.ElapsedMilliseconds.ToString("数据导入耗时：" + "0000"+"ms");             MessageBox.Show("数据导入完成");         }          private void dataGridView1_RowsAdded(object sender, DataGridViewRowsAddedEventArgs e)         {             for (int i = 0; i < dataGridView1.Rows.Count; i++)                  this.dataGridView1.Rows[i].HeaderCell.Value = (i + 1).ToString();         }          private void button2_Click(object sender, EventArgs e)         {             Stopwatch sw = new Stopwatch();             sw.Start();             DataTable dt = (dataGridView1.DataSource as DataTable);             //NPOIExcel.DataTableToExcel(dt, "d:\111.xlsx");//方式1             NPOIExcel.TableToExcel(dt, "d:\111.xlsx");//方式2             sw.Stop();             label2.Text = sw.ElapsedMilliseconds.ToString("数据导出耗时：" + "0000" + "ms");             MessageBox.Show("数据导出完成");         }     }  } 

using System; using System.Collections.Generic; using NPOI.HSSF.UserModel; using NPOI.SS.UserModel; using NPOI.XSSF.UserModel; using System.Data; using System.IO;  namespace npoi1 {     public class NPOIExcel     {         /// <summary>         /// 将excel导入到datatable         /// </summary>         /// <param name="filePath">excel路径</param>         /// <param name="isColumnName">第一行是否是列名</param>         /// <returns>返回datatable</returns>         public static DataTable ExcelToDataTable(string filePath, bool isColumnName)         {             DataTable dataTable = null;             FileStream fs = null;             DataColumn column = null;             DataRow dataRow = null;             IWorkbook workbook = null;             ISheet sheet = null;             IRow row = null;             ICell cell = null;             int startRow = 0;             try             {                 using (fs = File.OpenRead(filePath))                 {                     // 2007版本                     if (filePath.IndexOf(".xlsx") > 0)                         workbook = new XSSFWorkbook(fs);                     // 2003版本                     else if (filePath.IndexOf(".xls") > 0)                         workbook = new HSSFWorkbook(fs);                      if (workbook != null)                     {                         sheet = workbook.GetSheetAt(0);//读取第一个sheet，当然也可以循环读取每个sheet                         dataTable = new DataTable();                         if (sheet != null)                         {                             int rowCount = sheet.LastRowNum;//总行数                             if (rowCount > 0)                             {                                 IRow firstRow = sheet.GetRow(0);//第一行                                 int cellCount = firstRow.LastCellNum;//列数                                  //构建datatable的列                                 if (isColumnName)                                 {                                     startRow = 1;//如果第一行是列名，则从第二行开始读取                                     for (int i = firstRow.FirstCellNum; i < cellCount; ++i)                                     {                                         cell = firstRow.GetCell(i);                                         if (cell != null)                                         {                                             if (cell.StringCellValue != null)                                             {                                                 column = new DataColumn(cell.StringCellValue);                                                 dataTable.Columns.Add(column);                                             }                                         }                                     }                                 }                                 else                                 {                                     for (int i = firstRow.FirstCellNum; i < cellCount; ++i)                                     {                                         column = new DataColumn("column" + (i + 1));                                         dataTable.Columns.Add(column);                                     }                                 }                                  //填充行                                 for (int i = startRow; i <= rowCount; ++i)                                 {                                     row = sheet.GetRow(i);                                     if (row == null) continue;                                      dataRow = dataTable.NewRow();                                     for (int j = row.FirstCellNum; j < cellCount; ++j)                                     {                                         cell = row.GetCell(j);                                         if (cell == null)                                         {                                             dataRow[j] = "";                                         }                                         else                                         {                                             //CellType(Unknown = -1,Numeric = 0,String = 1,Formula = 2,Blank = 3,Boolean = 4,Error = 5,)                                             switch (cell.CellType)                                             {                                                 case CellType.Blank:                                                     dataRow[j] = "";                                                     break;                                                 case CellType.Numeric:                                                     short format = cell.CellStyle.DataFormat;                                                     //对时间格式（2015.12.5、2015/12/5、2015-12-5等）的处理                                                     if (format == 14 || format == 31 || format == 57 || format == 58)                                                         dataRow[j] = cell.DateCellValue;                                                     else                                                         dataRow[j] = cell.NumericCellValue;                                                     break;                                                 case CellType.String:                                                     dataRow[j] = cell.StringCellValue;                                                     break;                                             }                                         }                                     }                                     dataTable.Rows.Add(dataRow);                                 }                             }                         }                     }                 }                 return dataTable;             }             catch (Exception)             {                 if (fs != null)                 {                     fs.Close();                 }                 return null;             }         }          /// <summary>         /// 写入excel         /// </summary>         /// <param name="dt">datatable</param>         /// <param name="strFile">strFile</param>         /// <returns></returns>         public static bool DataTableToExcel(DataTable dt, string strFile)         {             bool result = false;             IWorkbook workbook = null;             FileStream fs = null;             IRow row = null;             ISheet sheet = null;             ICell cell = null;             try             {                 if (dt != null && dt.Rows.Count > 0)                 {                     workbook = new XSSFWorkbook();//HSSFWorkbook:是操作Excel2003以前（包括2003）的版本，扩展名是.xls  XSSFWorkbook:是操作Excel2007的版本，扩展名是.xlsx                     sheet = workbook.CreateSheet("Sheet0");//创建一个名称为Sheet0的表                     int rowCount = dt.Rows.Count;//行数                     int columnCount = dt.Columns.Count;//列数                      //设置列头                     row = sheet.CreateRow(0);//excel第一行设为列头                     for (int c = 0; c < columnCount; c++)                     {                         cell = row.CreateCell(c);                         cell.SetCellValue(dt.Columns[c].ColumnName);                     }                      //设置每行每列的单元格,                     for (int i = 0; i < rowCount; i++)                     {                         row = sheet.CreateRow(i + 1);                         for (int j = 0; j < columnCount; j++)                         {                             cell = row.CreateCell(j);//excel第二行开始写入数据                             cell.SetCellValue(dt.Rows[i][j].ToString());                         }                     }                     using (fs = File.OpenWrite(strFile))                     {                         workbook.Write(fs);//向打开的这个xls文件中写入数据                         result = true;                     }                 }                 return result;             }             catch (Exception ex)             {                 if (fs != null)                 {                     fs.Close();                 }                 Console.WriteLine(ex.StackTrace + ex.Message);                 return false;             }         }          /// <summary>         /// Excel导入成Datable         /// </summary>         /// <param name="file">导入路径(包含文件名与扩展名)</param>         /// <returns></returns>         public static DataTable ExcelToTable(string file)         {             DataTable dt = new DataTable();             IWorkbook workbook;             string fileExt = Path.GetExtension(file).ToLower();             using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))             {                 //XSSFWorkbook 适用XLSX格式，HSSFWorkbook 适用XLS格式                 if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(fs); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(fs); } else { workbook = null; }                 if (workbook == null) { return null; }                 ISheet sheet = workbook.GetSheetAt(0);                  //表头                 IRow header = sheet.GetRow(sheet.FirstRowNum);                 List<int> columns = new List<int>();                 for (int i = 0; i < header.LastCellNum; i++)                 {                     object obj = GetValueType(header.GetCell(i));                     if (obj == null || obj.ToString() == string.Empty)                     {                         dt.Columns.Add(new DataColumn("Columns" + i.ToString()));                     }                     else                         dt.Columns.Add(new DataColumn(obj.ToString()));                     columns.Add(i);                 }                 //数据                 for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++)                 {                     DataRow dr = dt.NewRow();                     bool hasValue = false;                     foreach (int j in columns)                     {                         dr[j] = GetValueType(sheet.GetRow(i).GetCell(j));                         if (dr[j] != null && dr[j].ToString() != string.Empty)                         {                             hasValue = true;                         }                     }                     if (hasValue)                     {                         dt.Rows.Add(dr);                     }                 }             }             return dt;         }          /// <summary>         /// Datable导出成Excel         /// </summary>         /// <param name="dt"></param>         /// <param name="file">导出路径(包括文件名与扩展名)</param>         public static void TableToExcel(DataTable dt, string file)         {             IWorkbook workbook;             string fileExt = Path.GetExtension(file).ToLower();             if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(); } else { workbook = null; }             if (workbook == null) { return; }             ISheet sheet = string.IsNullOrEmpty(dt.TableName) ? workbook.CreateSheet("Sheet1") : workbook.CreateSheet(dt.TableName);              //表头             IRow row = sheet.CreateRow(0);             for (int i = 0; i < dt.Columns.Count; i++)             {                 ICell cell = row.CreateCell(i);                 cell.SetCellValue(dt.Columns[i].ColumnName);             }              //数据             for (int i = 0; i < dt.Rows.Count; i++)             {                 IRow row1 = sheet.CreateRow(i + 1);                 for (int j = 0; j < dt.Columns.Count; j++)                 {                     ICell cell = row1.CreateCell(j);                     cell.SetCellValue(dt.Rows[i][j].ToString());                 }             }              //转为字节数组             MemoryStream stream = new MemoryStream();             workbook.Write(stream);             var buf = stream.ToArray();              //保存为Excel文件             using (FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write))             {                 fs.Write(buf, 0, buf.Length);                 fs.Flush();             }         }          /// <summary>         /// 获取单元格类型         /// </summary>         /// <param name="cell"></param>         /// <returns></returns>         private static object GetValueType(ICell cell)         {             if (cell == null)                 return null;             switch (cell.CellType)             {                 case CellType.Blank: //BLANK:                     return null;                 case CellType.Boolean: //BOOLEAN:                     return cell.BooleanCellValue;                 case CellType.Numeric: //NUMERIC:                     return cell.NumericCellValue;                 case CellType.String: //STRING:                     return cell.StringCellValue;                 case CellType.Error: //ERROR:                     return cell.ErrorCellValue;                 case CellType.Formula: //FORMULA:                 default:                     return "=" + cell.CellFormula;              }         }      }   }