I am not able to fetch single record from access database in C#.Net -

i doing project on library management system. want fetch data student using borrower number select query. code not working giving exception type mismatch in criteria expression @ line number 40 dadapter.fill(datatable);. please me. here code. thank :)

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.drawing; using system.linq; using system.text; using system.windows.forms; using system.data.oledb;  namespace librarymanagment { public partial class viewstudent : form {     private oledbconnection bookconn;     private oledbcommand oledbcmd = new oledbcommand();     //parameter mdsaputra.udl     private string connparam = @"provider=microsoft.jet.oledb.4.0;data source=e:\mini\database\library.mdb;persist security info=false";        public viewstudent()     {         bookconn = new oledbconnection(connparam);         initializecomponent();     }      private void btnview_click(object sender, eventargs e)     {         datagridview1.datasource = null;         datagridview1.rows.clear();         datagridview1.refresh();          oledbdataadapter dadapter = new oledbdataadapter("select * student borrowerno = '"+ this.txtborrowerno.text +"';", connparam);         oledbcommandbuilder cbuilder = new oledbcommandbuilder(dadapter);          datatable datatable = new datatable();         dataset ds = new dataset();          dadapter.fill(datatable);          (int = 0; < datatable.rows.count; i++)         {             datagridview1.rows.add(datatable.rows[i][0], datatable.rows[i][1], datatable.rows[i][2], datatable.rows[i][3], datatable.rows[i][4], datatable.rows[i][5], datatable.rows[i][6], datatable.rows[i][7]);         }     }           private void viewstudent_load(object sender, eventargs e)         {             // todo: line of code loads data 'librarydataset.student' table. can move, or remove it, needed.            // this.studenttableadapter4.fill(this.librarydataset.student);          }   } 

}

from error mentioned in comments, borrower no of type number , seems causing problem.

oledbdataadapter dadapter = new oledbdataadapter("select * student borrowerno = "+ this.txtborrowerno.text +";", connparam); 

notice have removed single quotes. use single quotes when data type string.