使用oledbconnection读取excel数据

以excel为数据源进行数据的导入，导入要注意的三个问题：

1、数据文件的存在时要删除，同时多个用户同时导入相同文件名的文件时的文件的处理；

2、要读取该excel文件中选中的sheet的内容；

3、当系统长期使用后，不能造成大量的垃圾文件。

主要代码如下：

 // add random number before filename (1)

 string filename = new Random().Next() + fuExcel.FileName;

//save file to given directory

string path = System.AppDomain.CurrentDomain.BaseDirectory + @"uploadExcels/" + filename;

if(File.Exists(path)) // delete the file if it exists. (3)
        File.Delete(path);

try
{
    Request.Files[0].SaveAs(path);
}
catch (Exception ex)
{
    PreExitExcel();
    ShowMessageBox("上传文件失败，服务器没有开启写入权限！+" + ex.Message);
    return;
}

// get the name of activesheet of the excel  (2)

string sheetName;

Excel.Application excel = new Application();
try
{
    System.Reflection.Missing miss = System.Reflection.Missing.Value;
    excel.Workbooks.Open(path, miss, miss, miss, miss, miss, miss, miss, miss, miss, miss, miss, miss, miss, miss);
    sheetName = ((Excel.Worksheet)excel.ActiveWorkbook.ActiveSheet).Name;
}
finally
{
    excel.Workbooks.Close();
    excel.Quit();
    excel = null;
}
// open the excel file as data source.
DataSet ds = new DataSet();
string connectionString = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=Yes;IMEX=1""", path);
OleDbConnection connection = new OleDbConnection(connectionString);
OleDbDataAdapter adapter = new OleDbDataAdapter("select * from [" + sheetName + "$]", connection);
adapter.Fill(ds);

// process the data source

......

 // delete the file after usage. (3)
try
{
    File.Delete(path);
}
catch
{}