title: Data type mismatch in criteria expression in c#
body: <p>I have a problem, when i m run my code then error is occured that ""<em>System.Data.OleDb.OleDbException: Data type mismatch in criteria expression.</em>"".
  And Datatype is Number.</p>
  
  <p>plz suggest me regarding that.</p>
  
  <p>"<em>Code</em></p>
  
  <pre><code> protected void btn_Save_Click(object sender, EventArgs e)
      {
          string str = ("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:/Users/Geeta/Desktop/eTimeTrackLite1.mdb;Persist Security Info=False;");
          OleDbConnection conn = new OleDbConnection(str);
          conn.Open();
          string query = "insert into Employees (EmployeeName,EmployeeCode,Designation,Grade,Team,Location,EmployementType,HolidayGroup) values ('" + txt_empname.Text + "','" + txt_code.Text + "', '"+ Convert.ToString(dp_designation.SelectedItem)+"', '"+Convert.ToString(dp_grade.SelectedItem)+"', '"+Convert.ToString(dp_team.SelectedItem)+"', '"+Convert.ToString(dp_location.SelectedItem)+"', '"+Convert.ToString(dp_emptype.SelectedItem)+"',  '"+Convert.ToString(dp_holigroup.SelectedItem)+"')";
          OleDbCommand cmd = new OleDbCommand(query, conn);
          cmd.ExecuteNonQuery();
          conn.Close();
          BindGridData();
      }
  </code></pre>
  
  <p>"Thanks"</p>