this.dataSet=new System.Data.DataSet();
   string connStr="Provider=MSDAORA.1;User ID=WMS;Data Source=ORCL;Password=wms";
   System.Data.OleDb.OleDbConnection Connection=new System.Data.OleDb.OleDbConnection(connStr);
   System.Data.OleDb.OleDbDataAdapter ap=new System.Data.OleDb.OleDbDataAdapter("select * from im_inventory",Connection);
   ap.Fill(this.dataSet,"im_inventory");
   this.dataGrid1.SetDataBinding(this.dataSet,"im_inventory");

System.Data.OleDb.OleDbConnection Connection

不用这么麻烦，你using了System.Data.OleDb就可以直接用了。

OleDbConnection con = ...