How to Remove ‘\0’ from a string in C#?

It seems you just want the string.Replace function (static method).

var cleaned = input.Replace("\0", string.Empty);

Edit: Here’s the complete code, as requested:

public static void funcTest (string sSubject, string sBody)
{
    try
    {
        MailMessage msg = new MailMessage();
        msg.To = XMLConfigReader.Email;
        msg.From = XMLConfigReader.From_Email;
        msg.Subject = sSubject;
        msg.Body = sBody.Replace("\0", string.Empty);
    }
    catch (Exception ex) 
    {
        string sMessage = ex.Message;     
        log.Error(sMessage, ex);   
    }
}