Populate a datagridview with sql query results

Here's your code fixed up. Next forget bindingsource

 var select = "SELECT * FROM tblEmployee";
 var c = new SqlConnection(yourConnectionString); // Your Connection String here
 var dataAdapter = new SqlDataAdapter(select, c); 

 var commandBuilder = new SqlCommandBuilder(dataAdapter);
 var ds = new DataSet();
 dataAdapter.Fill(ds);
 dataGridView1.ReadOnly = true; 
 dataGridView1.DataSource = ds.Tables[0];

Try binding your DataGridView to the DefaultView of the DataTable:

dataGridView1.DataSource = table.DefaultView;

You don't need bindingSource1

Just set dataGridView1.DataSource = table;

String strConnection = Properties.Settings.Default.BooksConnectionString;
SqlConnection con = new SqlConnection(strConnection);

SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = con;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "Select * from titles";
SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);

DataTable dtRecord = new DataTable();
sqlDataAdap.Fill(dtRecord);
dataGridView1.DataSource = dtRecord;