设置Calendar日期

        string year = this.TextBox2.Text;
        string month = this.TextBox3.Text;
        string day = this.TextBox4.Text;
        this.Label4.Text = "被重新设置的日期是：" + c1.SelectedDate.ToShortDateString();
        this.Calendar1.SelectedDate = Convert.ToDateTime(year + "-" + month + "-" + day);