Check out example codes for "how to look for substring in string in c#". It will help you in understanding the concepts better.

Code Example 1

public static string getBetween(string strSource, string strStart, string strEnd)
    int Start, End;
    if (strSource.Contains(strStart) && strSource.Contains(strEnd))
        Start = strSource.IndexOf(strStart, 0) + strStart.Length;
        End = strSource.IndexOf(strEnd, Start);
        return strSource.Substring(Start, End - Start);
        return "";

Code Example 2

String phrase = "this is the ultimate string";

Console.WriteLine(phrase.Contains("this")); //returns True
Console.WriteLine(phrase.Contains("python")); //returns False

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