Question

Here's my input:

sw.WriteLine("{0:MM/dd/yyyy HH:mm:ss tt} ", DateTime.Now + Convert.ToString(newurls[counter]));

and I get this output:

4/4/2016 2:46:57 PM14751

Then when I flip the two inputs like this:

sw.WriteLine(Convert.ToString(newurls[counter])  +  "{0:MM/dd/yyyy HH:mm:ss tt} ", DateTime.Now);

I get this output:

1459104/04/2016 14:48:02 PM

Note: newurls[counter] is changing all the time.

Back on point, I want it so that the DateTime now is in military time, but in front of newurls[counter. What I mean is, I want the output to be like this:

04/04/2016 14:48:02 PM14591

Why are the times switching back and forth from military and standard?

Answer 1

sw.WriteLine("{0:MM/dd/yyyy HH:mm:ss tt} ", DateTime.Now + Convert.ToString(newurls[counter]));

should probably be

sw.WriteLine("{0:MM/dd/yyyy HH:mm:ss tt} {1}", DateTime.Now, Convert.ToString(newurls[counter]));

In the first instance you are converting the datetime to a string and then adding it to the Convert.ToString results. In the second instance you are converting it first with your formatter and then concatinating the strings.

In my change above I am adding a placeholder for your second parameter in the string as {1}, that is where the Convert.ToString(newurls[counter]) will be placed. For more info see Composite Formatting.

Answer 2

When you are adding:

DateTime.Now + Convert.ToString(newurls[counter])

that's where you lose your date formating

I think what you want is:

sw.WriteLine("{0:MM/dd/yyyy HH:mm:ss tt} {1}", DateTime.Now , Convert.ToString(newurls[counter]));

Answer 3

您正在处理的问题是您正在处理两种完全不同的格式和值。

在第一个示例中，您将提供字符串格式：

"{0:MM/dd/yyyy HH:mm:ss tt} "

然后提供值

DateTime.Now + Convert.ToString(newurls[counter])

日期的默认ToString()实现是短通用版本。由于参数0不是DateTime，因此该值被视为字符串。您只需编写以下内容即可验证：

 sw.WriteLine(DateTime.Now + Convert.ToString(newurls[counter]));

解决方案是将不同的组件视为单独的项目：

sw.WriteLine("{0:MM/dd/yyyy HH:mm:ss tt} {1}",
    DateTime.Now,
    Convert.ToString(newurls[counter]));

您现在可以相互更改{1}和{0}的关系，并获得您的期望。如果您使用字符串格式，则从不需要使用+符号。只需将您的值写为逗号分隔列表，并使用花括号中的数字表示您传递的各个参数。在这种情况下，DateTime.Now首先被传递，因此我们将其称为{0}。第二次传递了Convert.ToString(newurls[counter])，因此我们将其称为{1}。

Why does my output change from military time to standard?

3 个答案: