private void but_add_Click(object sender, EventArgs e)
{
Database db = new Database();
Steel steel = new Steel();
steel.part_name_ = text_partname.Text;
steel.section_ = combo_section.Text;
steel.mat_ = combo_mat.Text;
db.add_steel(steel);
Autodesk.AutoCAD.ApplicationServices.Application.ShowAlertDialog("Add steel OK.");
}
public void add_steel(Steel steel)
{
steels_.Add(steel);
}