.NET (Core and Framework)

void FillData()
{
    // 1
    // Open connection
    using (SqlConnection c = new SqlConnection(DataConnectionString))
    {
        c.Open();
        // 2
        // Create new DataAdapter
        using (SqlDataAdapter a = new SqlDataAdapter("SELECT * FROM phoneBookTable", c))
        {
            // 3
            // Use DataAdapter to fill DataTable
            DataTable t = new DataTable();
            a.Fill(t);

            // 4
            // Render data onto the screen
            // dataGridView1.DataSource = t; // <-- From your designer
        }
    }
}

Imports System.Data.SqlClient
Public Class Form2

    Dim con As New SqlConnection

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try
            con.ConnectionString = "Data Source=.\SQLEXPRESS;" + _
                                    "AttachDbFilename=|DataDirectory|\Database1.mdf;" + _
                                    "Integrated Security=True;User Instance=True"
            con.Open()
            con.Close()

            Dim da As New SqlDataAdapter
            Dim dt As New DataTable
            Dim ds As New DataSet

            ds.Tables.Add(dt)
            con.Open()
            da = New SqlDataAdapter("SELECT * FROM phoneBookTable", con)
            da.Fill(dt)
            con.Close()


            Dim newRows As DataRow = dt.NewRow
            With newRows
                .Item(0) = "2"
            End With
            dt.Rows.Add(newRows)

            con.Open()
            Dim cb As New SqlCommandBuilder(da)
            da.Update(dt)
            con.Close()

            Dim newRows2 As DataRow = dt.NewRow
            With newRows2
                .Item(0) = "3"
            End With
            dt.Rows.Add(newRows2)

            con.Open()
            cb = New SqlCommandBuilder(da)
            da.Update(dt)
            con.Close()

            DataGridView1.DataSource = dt.DefaultView

        Catch ex As Exception
            MsgBox(ex.ToString)
            con.Close()
        End Try

       

    End Sub
End Class

void onValidating(object sender, CancelEventArgs e)
{
	TextBox senderBox = sender as TextBox;
				
	if (senderBox.Text.Length == 0)
	{
		e.Cancel = true;
		System.Media.SystemSounds.Beep.Play();
	}
}

myTextBox.Validating += new CancelEventHandler(onValidating);

I are Troll