private void tsbEdit_Click(object sender, EventArgs e)
{
if (labBookTypeID.Text == "")
{
this.showErrorMessage("เลือกข้อมูลที่จะแก้ไขก่อน");
return;
}
BookType booktype = new BookType();
booktype.BookTypeID = int.Parse(labBookTypeID.Text);
booktype.BookTypeName = txtBookTypeName.Text;
booktype.update();
this.showDgvBookType();
this.clear();
}