How can I get only the date and time from the string?

Question

In Form1 I have:

satelliteMapToRead = File.ReadAllText(localFilename + "satelliteMap.txt");

Then in the constructor:

ExtractImages.ExtractDateTime("image2.ashx?region=eu&time=", "&ir=true", satelliteMapToRead);

Then in the ExtractImages class i have:

public static void ExtractDateTime(string firstTag, string lastTag, string f) { int index = 0; int t = f.IndexOf(firstTag, index); int g = f.IndexOf(lastTag, index); string a = f.Substring(t, g - t); }

This an example of a string in the text file:

image2.ashx?region=eu&time=201309202145&ir=true

From this string i want that the variable g will contain only: 201309202145 And then to convert the variable a to date time : date 2013 09 20 - time 21 45

What I get in the variable a now is:

image2.ashx?region=eu&time=201309202215

And it's not what I need.

Ed Chapel · Accepted Answer · 2013-09-20 22:30:32Z

2

You are not accounting for the length of firstTag:

int t = f.IndexOf(firstTag, index) + firstTag.Length;

answered Sep 20, 2013 at 22:30

Ed Chapel

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1 Comment

user2760148 Over a year ago

Ed this is working indeed: int index = 0; int t = f.IndexOf(firstTag, index) + firstTag.Length; int g = f.IndexOf(lastTag, index); string a = f.Substring(t, g - t);

Zong · Accepted Answer · 2013-09-20 22:28:56Z

0

Since you're already doing it this way, juts use indexOf("time=") again to get 201309202215. Then the date/time is given by

DateTime.ParseExact(str, "yyyyMMddhhmmss", CultureInfo.InvariantCulture);

answered Sep 20, 2013 at 22:28

Zong

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1 Comment

user2760148 Over a year ago

Zong Zheng i did : DateTime dt = DateTime.ParseExact(a, "yyyyMMddhhmmss", CultureInfo.InvariantCulture); The variable a now contain 201309202215 but im getting an error/exception: FormatException: String was not recognized as a valid DateTime

Omada · Accepted Answer · 2013-09-20 22:30:02Z

Switch this line to:

int t = f.IndexOf(firstTag, index) + firstTag.Length;

IndexOf returns the position of the first character of your string. So in your example, t is actually zero. This is why a also has the first tag in it.

Omada using your line now the variable a contain: 201309202215&ir=true","/image2.ashx?reg

Tim Schmelter · Accepted Answer · 2013-09-20 22:34:43Z

Without error handling (missing parameters or invalid format):

string url = "image2.ashx?region=eu&time=201309202145&ir=true"; var queryString = System.Web.HttpUtility.ParseQueryString(url); DateTime dt = DateTime.ParseExact(queryString["time"], "yyyyMMddHHmm", CultureInfo.InvariantCulture);

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