using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string str1 = "021A,775U,000A,021A,1U2,206B,240,249,255B,260,263B,280,294,2U1,306B,336B,345,427,440,442,474,477,4U4,500,508,523,543L,580,584,772,802,P55,VB" ;

        string str2 = "772+240+802+P55+263B+1U2+VB";

        Console.WriteLine(ContainsAll(str1, str2));

        string str3 = "772+240+802+P55+263B+test+VB";

        Console.WriteLine(str1.ContainsAll(str2));

        Console.WriteLine(str1.ContainsAll(str3));

    }

    public static bool ContainsAll(string str1, string str2)

    {

        return !str2.Split('+')

            .Except(new HashSet<string>(str1.Split(',')))

            .Any();

    }

}

​

public static class StringExtensions

{

    /// <summary>Check if all the elements in this string exist in the comparison</summary>

    /// <param name="listOfAllValues">the CSV string that contains all the possible values</param>

    /// <param name="requriedElements">CSV of the values that all MUST exist in the source list</param>

    /// <param name="requiredElementsDelimiter">[Optional] delimiter to use for the requriedElements string</param>

    public static bool ContainsAll(this string listOfAllValues, string requiredElements, char requiredElementsDelimiter = '+')

    {

        return !requiredElements.Split(requiredElementsDelimiter)

            .Except(new HashSet<string>(listOfAllValues.Split(',')))

            .Any();

    }

}