Sorry Alvin, i couldn't see your Reference Card. :(

@sukhjinder82
I'm not sure this is an appropriate place for this kind of question but in the interest of helping out a fellow programmer here is one of the many ways you could solve this problem.

public static string SplitTheString(string theString)
{

// Argument Check
if (string.IsNullOrEmpty(theString))
{
return theString;
}

// Define the token to split the string on.
string splitToken = "_";

// Split the string using the "_" token
string[] splits = theString.Split(new string[] {splitToken}, StringSplitOptions.None);

// if splits have been found then return the first split together with the original token.
if (splits != null && splits.Length > 0)
{
return splits[0] + splitToken;
}

// no split was found, just return the original string.
return theString;

}