String.Format variable in concatenated string format

Question

I would like to put a variable in a composite format in String.Format. Value

String str = String.Format("{0:[what should I put here]}", mydate, myFormat};

so the result will depend on myFormat.

myFormat = "yyyy" => str = "2015"
myFormat = "hh:mm:ss" => str = "08:20:20"

I failed to complete

String.Format("{0:{1}}", mydate, myFormat}

and

String.Format("{0:{{1}}}", mydate, myFormat}

and

String.Format("{0:\{1\}}", mydate, myFormat}

Thanks everyone.

+3

string c # datetime string.format composite

Kenny Apr 24 15 at 9:59 am

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2 answers

If you want to format a date string, it will be much easier for you than your approach:

string myformat = "yyyy";
string secondFormat = "dd.MM.yyyy";
DateTime.Now.ToString(myformat) //2015
DateTime.Now.ToString(secondFormat) //24.04.2015

+3

Marco Apr 24 At 10:09 am

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Alessandro d'andria · Accepted Answer · 2015-04-24T10:06:30+0000

Your format string should look like this:

string str = "{{0:{0}}}";

Then you can format like this:

string format = string.Format(str, "yyyy");
format = string.Format(format, DateTime.Now); // this will give 2015