将 C# 日期时间转换为字符串并返回
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原文地址: http://stackoverflow.com/questions/10798980/
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convert C# date time to string and back
提问by axe
I'm converting C# date time to string. Later when I convert it back to DateTimeobject it appears that they are not equal.
我正在将 C# 日期时间转换为字符串。稍后当我将其转换回DateTime对象时，它们似乎不相等。
const string FMT = "yyyy-MM-dd HH:mm:ss.fff";
DateTime now1 = DateTime.Now;
string strDate = now1.ToString(FMT);
DateTime now2 = DateTime.ParseExact(strDate, FMT, CultureInfo.InvariantCulture);
Console.WriteLine(now1.ToBinary());
Console.WriteLine(now2.ToBinary());
Here is the example. Looks like everything is included in string format, when I print date both displays the same, but when I compare objects or print date in binary format I see the difference. It looks strange to me, could you please explain what is going on here?
这是示例。看起来所有内容都包含在字符串格式中，当我打印日期时两者显示相同，但是当我比较对象或以二进制格式打印日期时，我看到了差异。我觉得很奇怪，你能解释一下这里发生了什么吗？
Here is the output for the code above.
这是上面代码的输出。
-8588633131198276118
634739049656490000
采纳答案by Oded
You should use the roundtripformat specifier "O" or "o"if you want to preserve the value of the DateTime.
您应该使用的roundtrip格式说明“O”或“O”，如果你想保留的价值DateTime。
The "O" or "o" standard format specifier represents a custom date and time format string using a pattern that preserves time zone information. For DateTime values, this format specifier is designed to preserve date and time values along with the DateTime.Kind property in text. The formatted string can be parsed back by using the DateTime.Parse(String, IFormatProvider, DateTimeStyles) or DateTime.ParseExact method if the styles parameter is set to DateTimeStyles.RoundtripKind.
“O”或“o”标准格式说明符使用保留时区信息的模式表示自定义日期和时间格式字符串。对于 DateTime 值，此格式说明符旨在保留文本中的日期和时间值以及 DateTime.Kind 属性。如果样式参数设置为 DateTimeStyles.RoundtripKind，则可以使用 DateTime.Parse(String, IFormatProvider, DateTimeStyles) 或 DateTime.ParseExact 方法解析格式化的字符串。
Using your code (apart from changing the format string):
使用您的代码（除了更改格式字符串）：
const string FMT = "O";
DateTime now1 = DateTime.Now;
string strDate = now1.ToString(FMT);
DateTime now2 = DateTime.ParseExact(strDate, FMT, CultureInfo.InvariantCulture);
Console.WriteLine(now1.ToBinary());
Console.WriteLine(now2.ToBinary());
I get:
我得到：
-8588633127598789320
-8588633127598789320
回答by Dr. Wily's Apprentice
2 things:
2件事：
You can use the ParseExact overload that takes a DateTimeStyle parameter in order to specify
AssumeLocal.There will still be a small difference between now1 and now2 unless you increase the precision to 7 digits instead of 3: "yyyy-MM-dd HH:mm:ss.fffffff"
const string FMT = "yyyy-MM-dd HH:mm:ss.fffffff"; DateTime now1 = DateTime.Now; string strDate = now1.ToString(FMT); DateTime now2 = DateTime.ParseExact(strDate, FMT, CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal); Console.WriteLine(now1.ToBinary()); Console.WriteLine(now2.ToBinary());
您可以使用采用 DateTimeStyle 参数的 ParseExact 重载来指定
AssumeLocal.除非您将精度提高到 7 位而不是 3 位，否则 now1 和 now2 之间仍然会有很小的差异：“yyyy-MM-dd HH:mm:ss.fffffff”
const string FMT = "yyyy-MM-dd HH:mm:ss.fffffff"; DateTime now1 = DateTime.Now; string strDate = now1.ToString(FMT); DateTime now2 = DateTime.ParseExact(strDate, FMT, CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal); Console.WriteLine(now1.ToBinary()); Console.WriteLine(now2.ToBinary());
Even without the above changes, the calculated difference between now1 and now2 appears small, even though the binary values do not appear similar.
即使没有上述更改，计算出的 now1 和 now2 之间的差异也很小，即使二进制值看起来并不相似。
TimeSpan difference = now2.Subtract(now1);
Console.WriteLine(difference.ToString());
回答by Ashekur Rahman molla Asik
Just use this code it convert date time to string and string to date time
只需使用此代码即可将日期时间转换为字符串并将字符串转换为日期时间
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace DateTimeConvert { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { label1.Text = ConvDate_as_str(textBox1.Text); } public string ConvDate_as_str(string dateFormat) { try { char[] ch = dateFormat.ToCharArray(); string[] sps = dateFormat.Split(' '); string[] spd = sps[0].Split('.'); dateFormat = spd[0] + ":" + spd[1] + " " + sps[1]; DateTime dt = new DateTime(); dt = Convert.ToDateTime(dateFormat); return dt.Hour.ToString("00") + dt.Minute.ToString("00"); } catch (Exception ex) { return "Enter Correct Format like <5.12 pm>"; } } private void button2_Click(object sender, EventArgs e) { label2.Text = ConvDate_as_date(textBox2.Text); } public string ConvDate_as_date(string stringFormat) { try { string hour = stringFormat.Substring(0, 2); string min = stringFormat.Substring(2, 2); DateTime dt = new DateTime(); dt = Convert.ToDateTime(hour+":"+min); return String.Format("{0:t}", dt); ; } catch (Exception ex) { return "Please Enter Correct format like <0559>"; } } } }
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace DateTimeConvert { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { label1.Text = ConvDate_as_str(textBox1.Text); } public string ConvDate_as_str(string dateFormat) { try { char[] ch = dateFormat.ToCharArray(); string[] sps = dateFormat.Split(' '); string[] spd = sps[0].Split('.'); dateFormat = spd[0] + ":" + spd[1] + " " + sps[1]; DateTime dt = new DateTime(); dt = Convert.ToDateTime(dateFormat); return dt.Hour.ToString("00") + dt.Minute.ToString("00"); } catch (Exception ex) { return "Enter Correct Format like <5.12 pm>"; } } private void button2_Click(object sender, EventArgs e) { label2.Text = ConvDate_as_date(textBox2.Text); } public string ConvDate_as_date(string stringFormat) { try { string hour = stringFormat.Substring(0, 2); string min = stringFormat.Substring(2, 2); DateTime dt = new DateTime(); dt = Convert.ToDateTime(hour+":"+min); return String.Format("{0:t}", dt); ; } catch (Exception ex) { return "Please Enter Correct format like <0559>"; } } } }
回答by Taylor Lafrinere
Oded's answer is good but it didn't work for me for UTC dates. In order to get it to work for UTC dates, I needed to specify a DateTimeStyles value of "RoundtripKind" so that it didn't try to assume it was a local time. Here is the updated code from above:
Oded 的回答很好，但它不适用于 UTC 日期。为了让它适用于 UTC 日期，我需要指定“RoundtripKind”的 DateTimeStyles 值，以便它不会尝试假定它是当地时间。这是上面更新的代码：
const string FMT = "O";
DateTime now1 = DateTime.Now;
string strDate = now1.ToString(FMT);
DateTime now2 = DateTime.ParseExact(strDate, FMT, CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind);
Console.WriteLine(now1.ToBinary());
Console.WriteLine(now2.ToBinary());
Note, this works for both UTC and local dates.
请注意，这适用于 UTC 和本地日期。
回答by Jan 'splite' K.
If you dont need the string to be human-readable (like, you want to cipher it before storage), you can just call string str = dt1.ToBinary().ToString();and DateTime dt2 = DateTime.FromBinary(long.Parse(str));
如果您不需要该字符串是人类可读的（例如，您想在存储之前对其进行加密），您可以调用string str = dt1.ToBinary().ToString();并DateTime dt2 = DateTime.FromBinary(long.Parse(str));
DateTime now1 = DateTime.Now;
string strDate = now1.ToBinary().ToString();
DateTime now2 = DateTime.FromBinary(long.Parse(strDate));
Console.WriteLine(now1.ToBinary());
Console.WriteLine(now2.ToBinary());
