c#读取excel文件：c#创建、读取与修改excel文件

// Namespaces, Variables, and Constants
using System;
using System.Configuration;
using System.Data;
private OleDbDataAdapter da;
private DataTable dt;
private void Excel_Load(object sender, System.EventArgs e)
{
// Create the DataAdapter.
da = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", ConfigurationSettings.AppSettings["ExcelConnectString1"]);
// Create the insert command.
String insertSql = "INSERT INTO [Sheet1$] (CategoryID, CategoryName, Description) VALUES (?, ?, ?)";
da.InsertCommand = new OleDbCommand(insertSql, da.SelectCommand.Connection);
da.InsertCommand.Parameters.Add("@CategoryID", OleDbType.Integer, 0, "CategoryID");
da.InsertCommand.Parameters.Add("@CategoryName", OleDbType.Char, 15, "CategoryName");
da.InsertCommand.Parameters.Add("@Description", OleDbType.VarChar, 100, "Description");
// Create the update command.
String updateSql = "UPDATE [Sheet1$] SET CategoryName=?, Description=? " WHERE CategoryID=?";
da.UpdateCommand = new OleDbCommand(updateSql, da.SelectCommand.Connection);
da.UpdateCommand.Parameters.Add("@CategoryName", OleDbType.Char, 15, "CategoryName");
da.UpdateCommand.Parameters.Add("@Description", OleDbType.VarChar, 100, "Description");
da.UpdateCommand.Parameters.Add("@CategoryID", OleDbType.Integer, 0, "CategoryID");
// Fill the table from the Excel spreadsheet.
dt = new DataTable( );
da.Fill(dt);
// Define the primary key.
dt.PrimaryKey = new DataColumn[] {dt.Columns[0]};
// Records can only be inserted using this technique.
dt.DefaultView.AllowDelete = false;
dt.DefaultView.AllowEdit = true;
dt.DefaultView.AllowNew = true;
// Bind the default view of the table to the grid.
dataGrid.DataSource = dt.DefaultView;
}
private void updateButton_Click(object sender, System.EventArgs e)
{
da.Update(dt);
}

using System;
using System.IO;
using System.Data;
using System.Collections;
using System.Data.OleDb;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace DotNet.Utilities
{
  /// <summary>
  /// Excel操作类
  /// </summary>
  /// Microsoft Excel 11.0 Object Library
  public class ExcelHelper
  {
#region 数据导出至Excel文件
/// </summary>
/// 导出excel文件，自动返回可下载的文件流
/// </summary>
public static void DataTable1Excel(System.Data.DataTable dtData)
{
  GridView gvExport = null;
  HttpContext curContext = HttpContext.Current;
  StringWriter strWriter = null;
  HtmlTextWriter htmlWriter = null;
  if (dtData != null)
  {
curContext.Response.ContentType = "application/vnd.ms-excel";
curContext.Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
curContext.Response.Charset = "utf-8";
strWriter = new StringWriter();
htmlWriter = new HtmlTextWriter(strWriter);
gvExport = new GridView();
gvExport.DataSource = dtData.DefaultView;
gvExport.AllowPaging = false;
gvExport.DataBind();
gvExport.RenderControl(htmlWriter);
curContext.Response.Write("<meta http-equiv="Content-Type" content="text/html;charset=gb2312"/>" + strWriter.ToString());
curContext.Response.End();
  }
}
/// <summary>
/// 导出Excel文件，转换为可读模式
/// </summary>
public static void DataTable2Excel(System.Data.DataTable dtData)
{
  DataGrid dgExport = null;
  HttpContext curContext = HttpContext.Current;
  StringWriter strWriter = null;
  HtmlTextWriter htmlWriter = null;
  if (dtData != null)
  {
curContext.Response.ContentType = "application/vnd.ms-excel";
curContext.Response.ContentEncoding = System.Text.Encoding.UTF8;
curContext.Response.Charset = "";
strWriter = new StringWriter();
htmlWriter = new HtmlTextWriter(strWriter);
dgExport = new DataGrid();
dgExport.DataSource = dtData.DefaultView;
dgExport.AllowPaging = false;
dgExport.DataBind();
dgExport.RenderControl(htmlWriter);
curContext.Response.Write(strWriter.ToString());
curContext.Response.End();
  }
}
/// <summary>
/// 导出Excel文件，并自定义文件名
/// </summary>
public static void DataTable3Excel(System.Data.DataTable dtData, String FileName)
{
  GridView dgExport = null;
  HttpContext curContext = HttpContext.Current;
  StringWriter strWriter = null;
  HtmlTextWriter htmlWriter = null;
  if (dtData != null)
  {
HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8);
curContext.Response.AddHeader("content-disposition", "attachment;filename=" + HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8) + ".xls");
curContext.Response.ContentType = "application nd.ms-excel";
curContext.Response.ContentEncoding = System.Text.Encoding.UTF8;
curContext.Response.Charset = "GB2312";
strWriter = new StringWriter();
htmlWriter = new HtmlTextWriter(strWriter);
dgExport = new GridView();
dgExport.DataSource = dtData.DefaultView;
dgExport.AllowPaging = false;
dgExport.DataBind();
dgExport.RenderControl(htmlWriter);
curContext.Response.Write(strWriter.ToString());
curContext.Response.End();
  }
}
/// <summary>
/// 将数据导出至Excel文件
/// </summary>
/// <param name="Table">DataTable对象</param>
/// <param name="ExcelFilePath">Excel文件路径</param>
public static bool OutputToExcel(DataTable Table, string ExcelFilePath)
{
  if (File.Exists(ExcelFilePath))
  {
throw new Exception("该文件已经存在！");
  }
  if ((Table.TableName.Trim().Length == 0) || (Table.TableName.ToLower() == "table"))
  {
Table.TableName = "Sheet1";
  }
  //数据表的列数
  int ColCount = Table.Columns.Count;
  //用于记数，实例化参数时的序号
  int i = 0;
  //创建参数
  OleDbParameter[] para = new OleDbParameter[ColCount];
  //创建表结构的sql语句
  string TableStructStr = @"Create Table " + Table.TableName + "(";
  //连接字符串
  string connString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + ExcelFilePath + ";Extended Properties=Excel 8.0;";
  OleDbConnection objConn = new OleDbConnection(connString);
  //创建表结构
  OleDbCommand objCmd = new OleDbCommand();
  //数据类型集合
  ArrayList DataTypeList = new ArrayList();
  DataTypeList.Add("System.Decimal");
  DataTypeList.Add("System.Double");
  DataTypeList.Add("System.Int16");
  DataTypeList.Add("System.Int32");
  DataTypeList.Add("System.Int64");
  DataTypeList.Add("System.Single");
  //遍历数据表的所有列，用于创建表结构
  foreach (DataColumn col in Table.Columns)
  {
//如果列属于数字列，则设置该列的数据类型为double
if (DataTypeList.IndexOf(col.DataType.ToString()) >= 0)
{
  para[i] = new OleDbParameter("@" + col.ColumnName, OleDbType.Double);
  objCmd.Parameters.Add(para[i]);
  //如果是最后一列
  if (i + 1 == ColCount)
  {
TableStructStr += col.ColumnName + " double)";
  }
  else
  {
TableStructStr += col.ColumnName + " double,";
  }
}
else
{
  para[i] = new OleDbParameter("@" + col.ColumnName, OleDbType.VarChar);
  objCmd.Parameters.Add(para[i]);
  //如果是最后一列
  if (i + 1 == ColCount)
  {
TableStructStr += col.ColumnName + " varchar)";
  }
  else
  {
TableStructStr += col.ColumnName + " varchar,";
  }
}
i++;
  }
  //创建Excel文件及文件结构
  try
  {
objCmd.Connection = objConn;
objCmd.CommandText = TableStructStr;
if (objConn.State == ConnectionState.Closed)
{
  objConn.Open();
}
objCmd.ExecuteNonQuery();
  }
  catch (Exception exp)
  {
throw exp;
  }
  //插入记录的SQL语句
  string InsertSql_1 = "Insert into " + Table.TableName + " (";
  string InsertSql_2 = " Values (";
  string InsertSql = "";
  //遍历所有列，用于插入记录，在此创建插入记录的SQL语句
  for (int colID = 0; colID < ColCount; colID++)
  {
if (colID + 1 == ColCount) //最后一列
{
  InsertSql_1 += Table.Columns[colID].ColumnName + ")";
  InsertSql_2 += "@" + Table.Columns[colID].ColumnName + ")";
}
else
{
  InsertSql_1 += Table.Columns[colID].ColumnName + ",";
  InsertSql_2 += "@" + Table.Columns[colID].ColumnName + ",";
}
  }
  InsertSql = InsertSql_1 + InsertSql_2;
  //遍历数据表的所有数据行
  for (int rowID = 0; rowID < Table.Rows.Count; rowID++)
  {
for (int colID = 0; colID < ColCount; colID++)
{
  if (para[colID].DbType == DbType.Double && Table.Rows[rowID][colID].ToString().Trim() == "")
  {
para[colID].Value = 0;
  }
  else
  {
para[colID].Value = Table.Rows[rowID][colID].ToString().Trim();
  }
}
try
{
  objCmd.CommandText = InsertSql;
  objCmd.ExecuteNonQuery();
}
catch (Exception exp)
{
  string str = exp.Message;
}
  }
  try
  {
if (objConn.State == ConnectionState.Open)
{
  objConn.Close();
}
  }
  catch (Exception exp)
  {
throw exp;
  }
  return true;
}
/// <summary>
/// 将数据导出至Excel文件
/// </summary>
/// <param name="Table">DataTable对象</param>
/// <param name="Columns">要导出的数据列集合</param>
/// <param name="ExcelFilePath">Excel文件路径</param>
public static bool OutputToExcel(DataTable Table, ArrayList Columns, string ExcelFilePath)
{
  if (File.Exists(ExcelFilePath))
  {
throw new Exception("该文件已经存在！");
  }
  //如果数据列数大于表的列数，取数据表的所有列
  if (Columns.Count > Table.Columns.Count)
  {
for (int s = Table.Columns.Count + 1; s <= Columns.Count; s++)
{
  Columns.RemoveAt(s);  //移除数据表列数后的所有列
}
  }
  //遍历所有的数据列，如果有数据列的数据类型不是 DataColumn，则将它移除
  DataColumn column = new DataColumn();
  for (int j = 0; j < Columns.Count; j++)
  {
try
{
  column = (DataColumn)Columns[j];
}
catch (Exception)
{
  Columns.RemoveAt(j);
}
  }
  if ((Table.TableName.Trim().Length == 0) || (Table.TableName.ToLower() == "table"))
  {
Table.TableName = "Sheet1";
  }
  //数据表的列数
  int ColCount = Columns.Count;
  //创建参数
  OleDbParameter[] para = new OleDbParameter[ColCount];
  //创建表结构的SQL语句
  string TableStructStr = @"Create Table " + Table.TableName + "(";
  //连接字符串
  string connString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + ExcelFilePath + ";Extended Properties=Excel 8.0;";
  OleDbConnection objConn = new OleDbConnection(connString);
  //创建表结构
  OleDbCommand objCmd = new OleDbCommand();
  //数据类型集合
  ArrayList DataTypeList = new ArrayList();
  DataTypeList.Add("System.Decimal");
  DataTypeList.Add("System.Double");
  DataTypeList.Add("System.Int16");
  DataTypeList.Add("System.Int32");
  DataTypeList.Add("System.Int64");
  DataTypeList.Add("System.Single");
  DataColumn col = new DataColumn();
  //遍历数据表的所有列，用于创建表结构
  for (int k = 0; k < ColCount; k++)
  {
col = (DataColumn)Columns[k];
//列的数据类型是数字型
if (DataTypeList.IndexOf(col.DataType.ToString().Trim()) >= 0)
{
  para[k] = new OleDbParameter("@" + col.Caption.Trim(), OleDbType.Double);
  objCmd.Parameters.Add(para[k]);
  //如果是最后一列
  if (k + 1 == ColCount)
  {
TableStructStr += col.Caption.Trim() + " Double)";
  }
  else
  {
TableStructStr += col.Caption.Trim() + " Double,";
  }
}
else
{
  para[k] = new OleDbParameter("@" + col.Caption.Trim(), OleDbType.VarChar);
  objCmd.Parameters.Add(para[k]);
  //如果是最后一列
  if (k + 1 == ColCount)
  {
TableStructStr += col.Caption.Trim() + " VarChar)";
  }
  else
  {
TableStructStr += col.Caption.Trim() + " VarChar,";
  }
}
  }
  //创建Excel文件及文件结构
  try
  {
objCmd.Connection = objConn;
objCmd.CommandText = TableStructStr;
if (objConn.State == ConnectionState.Closed)
{
  objConn.Open();
}
objCmd.ExecuteNonQuery();
  }
  catch (Exception exp)
  {
throw exp;
  }
  //插入记录的SQL语句
  string InsertSql_1 = "Insert into " + Table.TableName + " (";
  string InsertSql_2 = " Values (";
  string InsertSql = "";
  //遍历所有列，用于插入记录，在此创建插入记录的SQL语句
  for (int colID = 0; colID < ColCount; colID++)
  {
if (colID + 1 == ColCount) //最后一列
{
  InsertSql_1 += Columns[colID].ToString().Trim() + ")";
  InsertSql_2 += "@" + Columns[colID].ToString().Trim() + ")";
}
else
{
  InsertSql_1 += Columns[colID].ToString().Trim() + ",";
  InsertSql_2 += "@" + Columns[colID].ToString().Trim() + ",";
}
  }
  InsertSql = InsertSql_1 + InsertSql_2;
  //遍历数据表的所有数据行
  DataColumn DataCol = new DataColumn();
  for (int rowID = 0; rowID < Table.Rows.Count; rowID++)
  {
for (int colID = 0; colID < ColCount; colID++)
{
  //因为列不连续，所以在取得单元格时不能用行列编号，列需得用列的名称
  DataCol = (DataColumn)Columns[colID];
  if (para[colID].DbType == DbType.Double && Table.Rows[rowID][DataCol.Caption].ToString().Trim() == "")
  {
para[colID].Value = 0;
  }
  else
  {
para[colID].Value = Table.Rows[rowID][DataCol.Caption].ToString().Trim();
  }
}
try
{
  objCmd.CommandText = InsertSql;
  objCmd.ExecuteNonQuery();
}
catch (Exception exp)
{
  string str = exp.Message;
}
  }
  try
  {
if (objConn.State == ConnectionState.Open)
{
  objConn.Close();
}
  }
  catch (Exception exp)
  {
throw exp;
  }
  return true;
}
#endregion
/// <summary>
/// 获取Excel文件数据表列表
/// </summary>
public static ArrayList GetExcelTables(string ExcelFileName)
{
  DataTable dt = new DataTable();
  ArrayList TablesList = new ArrayList();
  if (File.Exists(ExcelFileName))
  {
using (OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;Data Source=" + ExcelFileName))
{
  try
  {
conn.Open();
dt = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
  }
  catch (Exception exp)
  {
throw exp;
  }
  //获取数据表个数
  int tablecount = dt.Rows.Count;
  for (int i = 0; i < tablecount; i++)
  {
string tablename = dt.Rows[i][2].ToString().Trim().TrimEnd('$');
if (TablesList.IndexOf(tablename) < 0)
{
  TablesList.Add(tablename);
}
  }
}
  }
  return TablesList;
}
/// <summary>
/// 将Excel文件导出至DataTable(第一行作为表头)
/// </summary>
/// <param name="ExcelFilePath">Excel文件路径</param>
/// <param name="TableName">数据表名，如果数据表名错误，默认为第一个数据表名</param>
public static DataTable InputFromExcel(string ExcelFilePath, string TableName)
{
  if (!File.Exists(ExcelFilePath))
  {
throw new Exception("Excel文件不存在！");
  }
  //如果数据表名不存在，则数据表名为Excel文件的第一个数据表
  ArrayList TableList = new ArrayList();
  TableList = GetExcelTables(ExcelFilePath);
  if (TableName.IndexOf(TableName) < 0)
  {
TableName = TableList[0].ToString().Trim();
  }
  DataTable table = new DataTable();
  OleDbConnection dbcon = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + ExcelFilePath + ";Extended Properties=Excel 8.0");
  OleDbCommand cmd = new OleDbCommand("select * from [" + TableName + "$]", dbcon);
  OleDbDataAdapter adapter = new OleDbDataAdapter(cmd);
  try
  {
if (dbcon.State == ConnectionState.Closed)
{
  dbcon.Open();
}
adapter.Fill(table);
  }
  catch (Exception exp)
  {
throw exp;
  }
  finally
  {
if (dbcon.State == ConnectionState.Open)
{
  dbcon.Close();
}
  }
  return table;
}
/// <summary>
/// 获取Excel文件指定数据表的数据列表
/// </summary>
/// <param name="ExcelFileName">Excel文件名</param>
/// <param name="TableName">数据表名</param>
public static ArrayList GetExcelTableColumns(string ExcelFileName, string TableName)
{
  DataTable dt = new DataTable();
  ArrayList ColsList = new ArrayList();
  if (File.Exists(ExcelFileName))
  {
using (OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;Data Source=" + ExcelFileName))
{
  conn.Open();
  dt = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Columns, new object[] { null, null, TableName, null });
  //获取列个数
  int colcount = dt.Rows.Count;
  for (int i = 0; i < colcount; i++)
  {
string colname = dt.Rows[i]["Column_Name"].ToString().Trim();
ColsList.Add(colname);
  }
}
  }
  return ColsList;
}
  }
}