Question

I have a string looking something like this

string myString = "Master Language=\"C#\" MasterPageFile=\"~/masterpages/Libraries.master\"";

1. I need to verify that it contain the exact words Master and Language=”C#”
2. I cannot always guarantee that the words Master and Language will be placed like this, hence stuff like Contains(“Master Language”) wont do

I’ve been playing around with regex.IsMatch without any results for a while so if anyone could be able to help me I’d appreciate that!

Answer 1

Since you need to find the occurrences of the word in any order, you can use the following pattern:

string pattern = @"^(?=.*\bMaster\b)(?=.*Language=""C#"").+$";

This uses positive look-arounds to check for the existence of Master and Language="C#". Notice the use of the word-boundary meta-character, \b, which ensures that “Master” is an exact match. That ensures that a partial match in “MasterPage” won’t occur.

Example:

string[] inputs = 
{
    "Master Language=\"C#\" MasterPageFile=\"~/masterpages/Libraries.master\"", // true
    "Language=\"C#\" MasterPageFile=\"~/masterpages/Libraries.master\" Master", // true
    "Language=\"C#\" MasterPageFile=\"~/masterpages/Libraries.master\"" // false
};

string pattern = @"^(?=.*\bMaster\b)(?=.*Language=""C#"").+$";

foreach (var input in inputs)
{
    Console.WriteLine(Regex.IsMatch(input, pattern));
}