C#对Excel的操作

//1 首先引入npoi操作的程序集
引用 NPOI.dll Ionic.Zip.dll
using NPOI.SS.UserModel; //包含对excel进行操作的方法
using NPOI.HSSF.UserModel; //包含excel每个sheet的属性

（1）Excel读取数据、Excel写入数据

（2）项目导入、项目导出

/// <summary>
/// 从Excel读
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnReadFromExcel_Click(object sender, EventArgs e)
{
//从流stream中读取
using(Stream stream=new FileStream("/Files/myexcel.xls",FileMode.Open,FileAccess.Read))
{
//读取workbook
IWorkbook workbook=new HSSFWorkbook(stream);
ISheet sheet = workbook.GetSheetAt(0);
for (int i = 0; i < sheet.LastRowNum;i++ )
{
IRow row = sheet.GetRow(i);
foreach(ICell cell in row.Cells)
{
string c = cell.StringCellValue;
MessageBox.Show(c);
}
}
}
MessageBox.Show("ok,读取成功");
}

/// <summary>
/// 写入Excel
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnWriteToExcel_Click(object sender, EventArgs e)
{
//初始化workbook
IWorkbook workbook = new HSSFWorkbook();
//创建sheet
ISheet sheet = workbook.CreateSheet("班级表");
//创建row
IRow row = sheet.CreateRow(0);
//创建cell
ICell cell = row.CreateCell(0);
cell.SetCellType(CellType.STRING);
cell.SetCellValue("hello");
//写入流
using(Stream stream=new FileStream("/Files/myexcel2.xls",FileMode.OpenOrCreate,FileAccess.Write))
{
workbook.Write(stream);
}
MessageBox.Show("ok,写入成功");
}

/// <summary>
/// 导出到Excel
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnExportToExcel_Click(object sender, EventArgs e)
{
//获得数据表
List<Object> list = myORM_BLL.SelectAllModel(typeof(T_CUSTOMER));
//初始化workbook
IWorkbook workbook = new HSSFWorkbook();
//创建sheet
ISheet sheet = workbook.CreateSheet("T_CUSTOMER");
//遍历数据表  名称用反射获得,数据行直接获得
//创建头行headrow
IRow headrow = sheet.CreateRow(0);
Type type = typeof(T_CUSTOMER);
PropertyInfo[] props = type.GetProperties();
for(int i=0;i<props.Length; i++)
{
string propName = props[i].Name;
ICell cell = headrow.CreateCell(i);
cell.SetCellType(CellType.STRING);
cell.SetCellValue(propName);
}
//创建数据行
//遍历集合 每个对象创建一个行
for (int j = 0; j < list.Count;j++ )
{
IRow row = sheet.CreateRow(j + 1);
Object obj = list[j];
Type tp = obj.GetType();
PropertyInfo[] props2 = tp.GetProperties();
//对象的每个属性 创建一个Cell
for (int k = 0; k < props2.Length;k++ )
{
string propName2 = props2[k].Name;
object propValue2 = props2[k].GetValue(obj);
//对于每行创建cell，设置值
ICell cell = row.CreateCell(k);
cell.SetCellType(CellType.STRING);
cell.SetCellValue(propValue2.ToString());
}
}
//写入stream
using(Stream stream=new FileStream("/Files/exportdata.xls",FileMode.OpenOrCreate,FileAccess.Write))
{
workbook.Write(stream);
}
MessageBox.Show("导出成功");
}

/// <summary>
/// 把C#中类型转Excel中类型
/// </summary>
/// <param name="cTyName">C#中类型 的名称</param>
/// <returns>Excel中类型</returns>
private CellType CelltypeToCType(string cTyName)
{
switch (cTyName)
{
case "Int16":
case "Int64":
case "Int32": return CellType.NUMERIC;
case "String": return CellType.STRING;
case "Data":
case "DateTime": return CellType.FORMULA;
default: throw new Exception("未知类型：" + cTyName);
}
}

/// <summary>
/// 从DB直接导出到Excel
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnExportToExcelFromDB_Click(object sender, EventArgs e)
{
//初始化workbook，创建sheet
IWorkbook workbook = new HSSFWorkbook();
ISheet sheet = workbook.CreateSheet("T_CUSTOMER");
//打开conn ,发出cmd，reader查询
string sql = "SELECT * FROM T_CUSTOMER";
using(OracleConnection conn=OracleHelper.CreateConnection())
using (OracleCommand cmd = new OracleCommand(sql, conn))
using (OracleDataReader reader = cmd.ExecuteReader())
{
//根据查询字段数fieldcount创建headrow 及遍历字段创建cell
IRow headrow = sheet.CreateRow(0);
for (int i = 0; i < reader.FieldCount; i++)
{
ICell cell = headrow.CreateCell(i);
cell.SetCellType(CellType.STRING);
cell.SetCellValue(reader.GetName(i));
}
//循环reader查询，每一条查询，创建row 及遍历字段创建cell
int datarowIndex = 1; //数据行索引，从1开始
while(reader.Read())
{
IRow row = sheet.CreateRow(datarowIndex);
for (int i = 0; i < reader.FieldCount;i++ )
{
ICell cell = row.CreateCell(i);
cell.SetCellType(CellType.STRING);
cell.SetCellValue(reader.GetValue(i).ToString());
}
datarowIndex++;
}
}
//关闭连接
//写入stream
//写入stream
using (Stream stream = new FileStream("/Files/exportdataFromDB.xls", FileMode.OpenOrCreate, FileAccess.Write))
{
workbook.Write(stream);
}
MessageBox.Show("导出成功");
}

/// <summary>
/// 从Excel导入  OracleBulkCopy大数据导入
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnImportFromExcel_Click(object sender, EventArgs e)
{
//创建datatable
DataTable dt = new DataTable();
Type type = typeof(T_CUSTOMER);
PropertyInfo[] props = type.GetProperties();
DataColumn[] dcArr = new DataColumn[props.Length];
int j=0;
foreach(PropertyInfo prop in props)
{
string propName = prop.Name;
Type propTy = prop.PropertyType; //属性的类型
DataColumn dc = new DataColumn();
dc.ColumnName = propName;
dcArr[j] = dc; //把表的列 存入数组
dc.DataType = propTy; //列中数据的类型
dt.Columns.Add(dc);
j++;
}
//读取Excel文件,获得stream
using (Stream stream = new FileStream("/Files/exportdata.xls", FileMode.Open, FileAccess.Read))
{
//获得workbook
IWorkbook workbook = new HSSFWorkbook(stream);
//读取sheet
ISheet sheet = workbook.GetSheetAt(0);
//读取row 及行中的cell 放入一个datatable
for (int i = 1; i < sheet.LastRowNum;i++ )
{
IRow row = sheet.GetRow(i);
DataRow dr = dt.NewRow();
foreach(ICell cell in row.Cells)
{
if (dcArr[i-1].DataType.Name=="Int32")
{
dr[dcArr[i - 1]] = (Int32)cell.NumericCellValue; //还可能需 Convert.ToInt32
}
else if (dcArr[i - 1].DataType.Name == "String")
{
dr[dcArr[i - 1]] = cell.StringCellValue;
}
else if (dcArr[i - 1].DataType.Name == "DateTime?")
{
dr[dcArr[i - 1]] = (DateTime?)cell.DateCellValue;
}
else
{
throw new Exception("未知类型:" + cell.CellType);
}
}
dt.Rows.Add(dr); //把表的行加入表的行集合中,最终获得表
}
}
//OracleBulk
using (OracleBulkCopy bulkCopy = new OracleBulkCopy(OracleHelper.CreateConnection()))
{
bulkCopy.DestinationTableName = "T_CUSTOMER";
foreach (DataColumn dc in dcArr)
{
string columnName = dc.ColumnName;
bulkCopy.ColumnMappings.Add(columnName, columnName);
}
bulkCopy.WriteToServer(dt);
}
//把数据表插入DB
}

/// <summary>
/// 从Execel直接导入DB
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnImportToDBFromExcel_Click(object sender, EventArgs e)
{
//读取excel
using (Stream stream = new FileStream("/Files/exportdataFromDB.xls", FileMode.Open, FileAccess.Read))
{
IWorkbook workbook = new HSSFWorkbook(stream);
//获得sheet
ISheet sheet = workbook.GetSheetAt(0);

//行headrow 去除首行 获得含有':'列名数组
IRow headrow = sheet.GetRow(0);
string[] columnNameArr = new string[headrow.LastCellNum-1];
for (int i = 1; i < headrow.LastCellNum;i++ )
{
columnNameArr[i - 1] = ":" + headrow.Cells[i].StringCellValue;
}
StringBuilder sb=new StringBuilder();
sb.Append("INSERT INTO T_CUSTOMER VALUES(SE_T_CUSTOMER.NEXTVAL,").Append(string.Join(",",columnNameArr)).AppendLine(")");
//遍历行row 去除首行 获得参数数组
for (int j = 1; j < sheet.LastRowNum;j++ )
{
IRow row = sheet.GetRow(j);
//除0行 的每一行都有一个参数数组，里面有各个cell值的参数
//声明一个参数数组，并对其中的灭一个参数赋值
OracleParameter[] paraArr = new OracleParameter[row.LastCellNum - 1]; { for (int i = 0; i < paraArr.Length;i++ ) { paraArr[i] = new OracleParameter(); } }
for (int k = 1; k < row.LastCellNum; k++)
{
ICell cell = row.Cells[k];
paraArr[k - 1].ParameterName = columnNameArr[k - 1];
paraArr[k - 1].Value = (object)cell.StringCellValue; //判断 不需要
}
//除0每一行 都执 /插入DB
OracleHelper.ExecuteNonQuery(sb.ToString(), paraArr);
}
}
}