【C#】NPIO操作Excel
一、DataTable与Excel的文件读写
1、Excel导出到DataTable
using NPOI.SS.UserModel;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WindowsFormsApplication1.UserClass
{
class FileHelper
{
/// <summary>
/// 读取excel 默认第一行为标头
/// </summary>
/// <param name="strFileName">excel文档路径</param>
/// <returns></returns>
public static DataTable ImportExceltoDt(string strFileName)
{
DataTable dt = new DataTable();
IWorkbook wb;
using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
{
wb = WorkbookFactory.Create(file);
}
ISheet sheet = wb.GetSheetAt(0);
dt = ImportDt(sheet, 0, true);
return dt;
}
/// <summary>
/// 将制定sheet中的数据导出到datatable中
/// </summary>
/// <param name="sheet">需要导出的sheet</param>
/// <param name="HeaderRowIndex">列头所在行号，-1表示没有列头</param>
/// <returns></returns>
///
static DataTable ImportDt(ISheet sheet, int HeaderRowIndex, bool needHeader)
{
DataTable table = new DataTable();
IRow headerRow;
int cellCount;
try
{
if (HeaderRowIndex < 0 || !needHeader)
{
headerRow = sheet.GetRow(0);
cellCount = headerRow.LastCellNum;
for (int i = headerRow.FirstCellNum; i <= cellCount; i++)
{
DataColumn column = new DataColumn(Convert.ToString(i));
table.Columns.Add(column);
}
}
else
{
headerRow = sheet.GetRow(HeaderRowIndex);
cellCount = headerRow.LastCellNum;
for (int i = headerRow.FirstCellNum; i <= cellCount; i++)
{
if (headerRow.GetCell(i) == null)
{
if (table.Columns.IndexOf(Convert.ToString(i)) > 0)
{
DataColumn column = new DataColumn(Convert.ToString("重复列名" + i));
table.Columns.Add(column);
}
else
{
DataColumn column = new DataColumn(Convert.ToString(i));
table.Columns.Add(column);
}
}
else if (table.Columns.IndexOf(headerRow.GetCell(i).ToString()) > 0)
{
DataColumn column = new DataColumn(Convert.ToString("重复列名" + i));
table.Columns.Add(column);
}
else
{
DataColumn column = new DataColumn(headerRow.GetCell(i).ToString());
table.Columns.Add(column);
}
}
}
int rowCount = sheet.LastRowNum;
for (int i = (HeaderRowIndex + 1); i <= sheet.LastRowNum; i++)
{
try
{
IRow row;
if (sheet.GetRow(i) == null)
{
row = sheet.CreateRow(i);
}
else
{
row = sheet.GetRow(i);
}
DataRow dataRow = table.NewRow();
for (int j = row.FirstCellNum; j <= cellCount; j++)
{
try
{
if (row.GetCell(j) != null)
{
switch (row.GetCell(j).CellType)
{
case CellType.String:
string str = row.GetCell(j).StringCellValue;
if (str != null && str.Length > 0)
{
dataRow[j] = str.ToString();
}
else
{
dataRow[j] = null;
}
break;
case CellType.Numeric:
if (DateUtil.IsCellDateFormatted(row.GetCell(j)))
{
dataRow[j] = DateTime.FromOADate(row.GetCell(j).NumericCellValue);
}
else
{
dataRow[j] = Convert.ToDouble(row.GetCell(j).NumericCellValue);
}
break;
case CellType.Boolean:
dataRow[j] = Convert.ToString(row.GetCell(j).BooleanCellValue);
break;
case CellType.Error:
dataRow[j] = ErrorEval.GetText(row.GetCell(j).ErrorCellValue);
break;
case CellType.Formula:
switch (row.GetCell(j).CachedFormulaResultType)
{
case CellType.String:
string strFORMULA = row.GetCell(j).StringCellValue;
if (strFORMULA != null && strFORMULA.Length > 0)
{
dataRow[j] = strFORMULA.ToString();
}
else
{
dataRow[j] = null;
}
break;
case CellType.Numeric:
dataRow[j] = Convert.ToString(row.GetCell(j).NumericCellValue);
break;
case CellType.Boolean:
dataRow[j] = Convert.ToString(row.GetCell(j).BooleanCellValue);
break;
case CellType.Error:
dataRow[j] = ErrorEval.GetText(row.GetCell(j).ErrorCellValue);
break;
default:
dataRow[j] = "";
break;
}
break;
default:
dataRow[j] = "";
break;
}
}
}
catch (Exception exception)
{
}
}
table.Rows.Add(dataRow);
}
catch (Exception exception)
{
//wl.WriteLogs(exception.ToString());
}
}
}
catch (Exception exception)
{
//wl.WriteLogs(exception.ToString());
}