如何控制DateTimePicker中的时间间隔

Question

我在指定的表单上有一个DateTimePicker控件,如下所示:

dtpEntry.Format = DateTimePickerFormat.Custom;
dtpEntry.CustomFormat = "dd/MM/yyyy hh:mm:ss";
dtpEntry.ShowUpDown = true;

我希望用户只能以5分钟的增量递增或递减时间.

关于如何实现这一目标的任何建议？

Answer 1

可以通过观察ValueChanged事件并覆盖该值来实现.这个样本表格效果很好:

public partial class Form1 : Form {
    public Form1() {
        InitializeComponent();
        dateTimePicker1.CustomFormat = "dd/MM/yyyy hh:mm";
        dateTimePicker1.Format = DateTimePickerFormat.Custom;
        dateTimePicker1.ShowUpDown = true;
        dateTimePicker1.Value = DateTime.Now.Date.AddHours(DateTime.Now.Hour);
        mPrevDate = dateTimePicker1.Value;
        dateTimePicker1.ValueChanged += new EventHandler(dateTimePicker1_ValueChanged);
    }
    private DateTime mPrevDate;
    private bool mBusy;

    private void dateTimePicker1_ValueChanged(object sender, EventArgs e) {
        if (!mBusy) {
            mBusy = true;
            DateTime dt = dateTimePicker1.Value;
            if ((dt.Minute * 60 + dt.Second) % 300 != 0) {
                TimeSpan diff = dt - mPrevDate;
                if (diff.Ticks < 0) dateTimePicker1.Value = mPrevDate.AddMinutes(-5);
                else dateTimePicker1.Value = mPrevDate.AddMinutes(5);
            }
            mBusy = false;
        }
        mPrevDate = dateTimePicker1.Value;
    }
}

Answer 2

我已经改变了SixOThree的答案,以消除Necromporph发现的错误.它应该是这样的:

在课堂里

private DateTime prevTimePicker1;
private bool navigatingDateTimePicker = false;

在构造函数中

prevTimePicker1 = dateTimePickerStart.Value;
navigatingDateTimePicker = false;

事件

private void dateTimePickerStart_ValueChanged(object sender, EventArgs e)
{
  if (!navigatingDateTimePicker) {
    /* First set the navigating flag to true so this method doesn't get called again while updating */
    navigatingDateTimePicker = true;

    /* using timespan because that's the only way I know how to round times well */
    TimeSpan tempTS = dateTimePickerStart.Value - dateTimePickerStart.Value.Date;
    TimeSpan roundedTimeSpan;

    TimeSpan TDBug = dateTimePickerStart.Value - prevTimePicker1;
    if (TDBug.TotalMinutes == 59)
    {
        // first: if we are going back and skipping an hour it needs an adjustment
        roundedTimeSpan = TimeSpan.FromMinutes(5 * Math.Floor((tempTS.TotalMinutes - 60) / 5));
        dateTimePickerStart.Value = dateTimePickerStart.Value.Date + roundedTimeSpan;
    }
    else if (dateTimePickerStart.Value > prevTimePicker1)
    {
        // round up to the nearest interval
        roundedTimeSpan = TimeSpan.FromMinutes(5 * Math.Ceiling(tempTS.TotalMinutes / 5));
        dateTimePickerStart.Value = dateTimePickerStart.Value.Date + roundedTimeSpan;
    } else {
        // round down to the nearest interval from prev
        roundedTimeSpan = TimeSpan.FromMinutes(5 * Math.Floor(tempTS.TotalMinutes / 5));
        dateTimePickerStart.Value = dateTimePickerStart.Value.Date + roundedTimeSpan;
    }
    navigatingDateTimePicker = false;
  }
  prevTimePicker1 = dateTimePickerStart.Value;
}