如何将数据库中保存的时间与当前系统时间进行比较？ [英] How can I compare a time saved in database with the current system time?

问题描述

我有一个名为Events的表，其中有很多列，其中一个是时间表示在24/04/2015 12:00:00 AM格式。

我只需要获取时间列，每当指定的时间到达系统时，都会显示一条弹出消息。

这是我的代码（以主表格加载的方法）

我试过了这不会弹出一条消息，PLZ帮助。

I have a table called Events where there are many columns and one of them is Time represented in 24/04/2015 12:00:00 AM format.
All I need is to fetch the time column and whenever the specified time arrives in system, a popup message should be displayed.
Here is My code (A method coded in the main form load)
I tried this but it doesnt popup a message, plz help.

public void Reminders()
{
    SqlCeConnection conn = new SqlCeConnection("Data Source=E:\\Project Final_Year\\Project Final\\MyProject\\ERU Implementation\\VirtualPetedit\\VirtualPet\\MyDB.sdf");
    string query = "SELECT time FROM Events";
    SqlCeDataReader r;
    DateTime thisDay = DateTime.Today; 

    try
    {
        conn.Open();
        SqlCeCommand command = new SqlCeCommand(query, conn);
        r  = command.ExecuteReader();
        //if (r.HasRows)
        //{
            while (r.Read())
            {
                if (r.GetDateTime(0)  == thisDay )
                {
                    VirtualPet.Popup popup = new VirtualPet.Popup();
                    popup.Reminder();
                }
            }
        //}
       /* else
        {
            MessageBox.Show("No Reminder times currently");                          
        }*/
        conn.Close(); 
    }
    catch (Exception ex)
    { 
        MessageBox.Show(ex.Message.ToString());
    }
}

推荐答案

Hi
今日格式/数据类型的输出不等于您在数据库中拥有什么，这意味着在数据库中，如果您想将此格式/数据类型与当前日期和时间进行比较（在本例中为今天），您可以使用此格式的日期和时间4/04/2015 12:00:00 AM你需要这样做：

Hi The output of thisday format/datatype is not equle with what ever you have in your database, which means in database you have Date&Time with this format 4/04/2015 12:00:00 AM if you want to compare this format/datatype with current Date&Time (in this case thisday) you need to do like this:

DateTime thisDay = DateTime.Today;
DateTime tag = r.GetDateTime(0);
int result = DateTime.Compare(thisDay, tag);
if (result < 0)
         relationship = "is earlier than";
      else if (result == 0)
         relationship = "is the same time as";         
      else
         relationship = "is later than";

其他相关实用代码：

Other related useful codes:

DateTime myDateTime = DateTime.Now;
string sqlFormattedDate = myDateTime.ToString("yyyy-MM-dd HH:mm:ss");

相关链接：

http://www.java2s.com/Tutorial/CSharp/0560__ADO.Net/SqlDataReaderGetStringGetDateTime.htm [ ^ ]

https：// msdn .microsoft.com / zh-cn / library / system.datetime.compare（v = vs.110）.aspx [ ^ ]

http://www.dotnetperls.com/datetime-format [<小时ef =http://www.dotnetperls.com/datetime-formattarget =_ blanktitle =New Window> ^ ]

https://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110） .aspx [ ^ ]

R，

Aydin

Related Links:
http://www.java2s.com/Tutorial/CSharp/0560__ADO.Net/SqlDataReaderGetStringGetDateTime.htm[^]
https://msdn.microsoft.com/en-us/library/system.datetime.compare(v=vs.110).aspx[^]
http://www.dotnetperls.com/datetime-format[^]
https://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110).aspx[^]
R,
Aydin

这篇关于如何将数据库中保存的时间与当前系统时间进行比较？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！