private void showDgvBookType()
{
DataTable dt = new DataTable();
// สร้างอ็อบเจกต์ของคลาส BookType
BookType booktype = new BookType();
dt = booktype.read();
dgvBookType.DataSource = dt;
}
private void showCboBookType()
{
BookType booktype = new BookType();
DataTable dt = new DataTable();
dt = booktype.read();
cboBookTypeID.DataSource = dt;
cboBookTypeID.DisplayMember = "BookTypeName";
cboBookTypeID.ValueMember = "BookTypeID";
cboBookTypeID.Text = "";
}