private void button1_Click(object sender, EventArgs e)
{
if (dateTimePicker1.Value <= dateTimePicker2.Value)
{
bool b = WorkWithDB.AddDov(dateTimePicker1.Value, dateTimePicker2.Value);
if (b == true)
{
}
else
{
}
}
else
{
MessageBox.Show("Некорректно выбрана дата");
}
}