Find and Replace Text in Text / HTML Files

public void ReplaceInFile(string filePath,string replaceText,string findText)

{

    try

    {

         System.IO.StreamReader objReader;

         objReader= new System.IO.StreamReader(filePath);

         string content= objReader.ReadToEnd();

         objReader.Close();

         content= Regex.Replace(content,findText,replaceText);

         StreamWriter writer= new StreamWriter(filePath);

         writer.Write(content);

         writer.Close();

    }

     catch(IOException iexp)

{

   throw;

}