How to replace all the text before a word with a blank space using Regex.Replace in C# -

i'm having problems trying replace text before word using c# want delete text found before specific word. tried didn't work

    string filecomplete = file.readalltext(path.getfullpath(ofd.filename));     string nonimportant = ".*?(?=word)";     string file = system.text.regularexpressions.regex.replace(filecomplete,     nonimportant, string.empty); 

what want keep text after word , delete before.

thanks,

following option uses matchevaluator syntax of regex.replace. note need put word in place , capture comes after in capture group via ().

string nonimportant = ".*?(word.*)"; string st = "aslkfdalksdwordewot"; string file = regex.replace(st, nonimportant, (match m) => string.format("{0}",m.groups[1]));