CMS_Migration_Utility.formMigration.ReplaceURLs C# (CSharp) Method

        private int ReplaceURLs()
        {
            string matchText = @"href=""";

            DBLookup dbLookup = new DBLookup();

            int numReplaced = 0;
            for (int loc = centerContent.IndexOf(matchText); loc != -1; loc = centerContent.IndexOf(matchText, loc + matchText.Length))
            {
                string lookupText = string.Empty;
                int startLoc = loc + matchText.Length;
                lookupText = centerContent.Substring(startLoc, centerContent.IndexOf('"', startLoc) - startLoc);
                string fullText = lookupText;
                lookupText = lookupText.Trim();
                lblCurrentURL.Text = lookupText;
                Application.DoEvents();

                //if (!IsValidLink(lookupText)) continue;
                List<string> foundNodes = new List<string>();
                //Make sure to search for lookup text only when non-blank URL is found
                if (!string.IsNullOrWhiteSpace(lookupText))
                {
                    string startURLText = "http", endURLText = "energy.gov/";
                    int startURLpos = lookupText.IndexOf(startURLText), endURLpos = lookupText.IndexOf(endURLText);

                    if (startURLpos != -1 && endURLpos != -1) // if it is a fully qualified URL remove server/domain name from search string
                    {
                        string eereURLText = lookupText.Substring(startURLpos, endURLpos + endURLText.Length - startURLpos);
                        lookupText = lookupText.Replace(eereURLText, "");
                    }

                    foundNodes = dbLookup.PerformDBLookup(lookupText);
                }

                if (foundNodes.Count > 0)
                {
                    centerContent = centerContent.Replace(fullText, foundNodes[0]);
                    numReplaced++;
                    txtReplaced.Text += fullText + Environment.NewLine;
                }
                else
                {
                    if (fullText.IndexOf("node/") == -1)
                    {
                        txtAttention.Text += fullText + Environment.NewLine;
                    }
                }
            }
            return numReplaced;
        }