ADO.NET查询语句总是报错为什么？在线等，挺急的

Question

string SQL="SELECT * FROM MobileBrand";            DataTable dt=new DataTable();            SqlDataAdapter adapter = new SqlDataAdapter(SQL,ConStr);            adapter.Fill(dt);            this.cboBrand.DisplayMember="Brand";            this.cboBrand.ValueMember="BrandID";            this.cboBrand.DataSource = dt;