为什么不运行这一行啊？总是跳过去，然后提示说违反了约束主键，说主键不能重复

为什么不运行红色的这一行啊？总是跳过去，然后提示说违反了约束主键，说主键不能重复
请指教！！！
procedure TForm1.Button2Click(Sender: TObject);
begin
with ADOTableStore do
begin
first;
while not eof do
begin
if((edit1.Text=fieldbyname('StorehouseID').AsString) and (edit2.Text=fieldbyname('Sbin').AsString)) then
begin
ShowMessage('该位已经存货，请选择别的货位！');
edit1.Text:='';
edit2.Text:='';
end;

if ((edit1.Text='')or (edit2.Text='')or(edit3.Text='')or(edit4.Text='')or(edit5.Text='')or(edit6.Text='')or(edit7.Text='')or(edit8.Text='')or(edit9.Text='')or(edit10.Text='')or(edit11.Text='')or(edit12.Text='')or(edit13.Text='')or(edit14.Text='')or(edit15.Text='')) then
begin
ShowMessage('信息填写不完整！')
end
else
begin
edit;
append;
fieldbyname('StorehouseID').AsString:=edit1.Text;
fieldbyname('Sbin').AsString:=edit2.Text;
fieldbyname('ItemID').AsString:=edit3.Text;
fieldbyname('Sfrom').AsString:=edit4.Text;
fieldbyname('SIntoQty').AsString:=edit5.Text;
post;
Refresh;
showmessage('存货成功！');
end;

break;
end;
next;

end;
end;