c# winform 中导入Excel 的问题 ！

OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" EXCEL的本地路径 ";Extended Properties=Excel 8.0;");
conn.Open();
string strExcel = "";
OleDbDataAdapter myCommand = null;
strExcel = string.Format("select '号码' from [这里填你的EXCEL左下角的工作表名$]");
myCommand = new OleDbDataAdapter(strExcel,conn);
DataTable dt=new DataTable();
myCommand .Fill(dt);//把所有结果填充到dt里面
string rusult="":
for(int i=0;i<dt.Row.count;i++)
{
rusult+=dt.Rows[i][0].ToString()+";";//遍历所有号码相加
}
textbox1.Text=rusult;