这就是你需要的一切。请注意，这很可怕。

Here's all you need. Be warned, it's scary.

public string AddDay(string fromTextBox)
{
    var baseDate = DateTime.Parse(fromTextBox);
    return baseDate.AddDays(1).ToString(CultureInfo.InvariantCulture);
}

您可以使用的 ValueChanged 事件DateTimePicker 。

You can use the ValueChanged event of the DateTimePicker.

private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
{
    DateTime date = dateTimePicker1.Value;
    textbox1.Text = date.AddDays(1).ToShortDateString();
    textbox2.Text = date.AddDays(2).ToShortDateString();
    textbox3.Text = date.AddDays(3).ToShortDateString();
    textbox4.Text = date.AddDays(4).ToShortDateString();
}