我在winforms C#中将exceldb文件上传到sql server时遇到了麻烦

我正在尝试创建一个Excel数据上传器，以便使用C#中的Winforms将Excel文件上传到SQL Server。

在bulkcopy.WriteToServer(dr);之后，我得到了这个错误：

多步骤OLE DB操作生成错误。检查每个OLE DB状态值（如果可用）。没有完成任何工作
用于查看链接的Microsoft Excel工作表的连接已丢失。

我在这里得到了关于regedit的信息，并试图遵循它，但仍然出现了相同的错误：

class Pass
{
    static string _excelfilepath;
    public static string excelfilepath { get { return _excelfilepath; } set { _excelfilepath = value; } }
    public void importdatafromexcel()
    {
        //declare variables - edit these based on your particular situation
        string ssqltable = "tStudent";
        // make sure your sheet name is correct, here sheet name is sheet1, so you can change your sheet name if have different
        string myexceldataquery = "select idnum,fname,gname,mname,coacro,year,yrstat,sex,stat,telno,addr1,addr2,addr3,dbirth,mothname,fathname,civstat,religion,hssch from [masterlist$]";
        try
        {
            //create our connection strings
            string sexcelconnectionstring = @"provider=microsoft.jet.oledb.4.0;data source=" + _excelfilepath +
            ";extended properties=" + "'"excel 8.0;hdr=yes;'"";
            string ssqlconnectionstring = @"Data Source=LYNDON-PC'LYNDON;Initial Catalog=trial;Persist Security Info=True;User ID=sa;Password=14323531";
            //execute a query to erase any previous data from our destination table
            string sclearsql = "delete from " + ssqltable;
            SqlConnection sqlconn = new SqlConnection(ssqlconnectionstring);
            SqlCommand sqlcmd = new SqlCommand(sclearsql, sqlconn);
            sqlconn.Open();
            sqlcmd.ExecuteNonQuery();
            sqlconn.Close();
            //series of commands to bulk copy data from the excel file into our sql table
            OleDbConnection oledbconn = new OleDbConnection(sexcelconnectionstring);
            OleDbCommand oledbcmd = new OleDbCommand(myexceldataquery, oledbconn);
            oledbconn.Open();
            OleDbDataReader dr = oledbcmd.ExecuteReader();
            SqlBulkCopy bulkcopy = new SqlBulkCopy(ssqlconnectionstring);
            bulkcopy.DestinationTableName = ssqltable;
            while (dr.Read())
            {
                bulkcopy.WriteToServer(dr);
            }
            oledbconn.Close();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
}

这个错误意味着什么，并获取将Excel文件上传到SQL Server数据库中的表的代码。。。

bulkcopy.WriteToServer(dr);

while (dr.Read())
{
    bulkcopy.WriteToServer(dr);
}