I am trying to parse the following string coming as an input from a text file:

Eurex  App: X_RISK     Trader: TTADM  XXX 100     UL: TTADM Workstation: xx.x.x.xx Server: xx.xx.xx.xx
LIFFE  App: X_RISK     Trader: TTADM  XXX 100     UL: TTADM Workstation: xx.x.X.xx Server: xx.xx.xx.xx

I want to be able to extract the following values and put them into an array of datarows.  

Eurex    X_RISK    TTADM  XXX 100    TTADM    xx.x.x.xx    xx.xx.xx.xx
Eurex    X_RISK    TTADM  XXX 100    TTADM    xx.x.x.xx    xx.xx.xx.xx
Eurex    X_RISK    TTADM  XXX 100    TTADM    xx.x.x.xx    xx.xx.xx.xx

I got it to a point where I am almost there, but still not quite I am having some difficulties how to get rid of the text ending with the double columns ":" and keep only the value I need so I can place them in my data table.

Please look at my code below, any help and suggestions are highly appreciated.

         public DataSet ConvertNew(string sLogFile)
        {
            if (!System.IO.File.Exists(sLogFile))
                return null;//fail file not found

            stream = new StreamReader(sLogFile, true);
            //Create a new data set
            DataSet dsFile = new DataSet("File");

            DataTable dtTable = dsFile.Tables.Add("Data");

            dtTable.Columns.Add("Exchange", typeof(string));
            dtTable.Columns.Add("Application", typeof(string));
            dtTable.Columns.Add("Trader", typeof(string));
            dtTable.Columns.Add("UL", typeof(string));
            dtTable.Columns.Add("Workstation", typeof(string));
            dtTable.Columns.Add("Server", typeof(string));

            Regex r = new Regex(",(?=([^\"]*\"[^\"]*\")*(?![^\"]*\"))");
            Regex regExpr = new Regex("\\s\\S");
            Regex patternExpr = new Regex("(App:|Trader:|UL:|Workstation:|Server:|:)");

            // Get the first line of data from the input (log) file.
            val = NextLine(stream);

            //Strip out each field and insert in DataTable
            int sStart;//used as a placeholder for our current location
            int nCount;//used to determine which field / column we are currently extracting
            string sTemp;//used to temporarily hold the field pulled out by RegEx in order to trim the quotation marks from the ends of the fiel (if any)

            //Data row object used to set values
            DataRow drRow;

            while (val != "")//val is empty when the input stream has been read to the end
            {
                sStart = 0;
                nCount = 0;

                //create a new row
                drRow = dtTable.NewRow();

                //Iterate through all the matches (match=field in current row)           
                foreach (Match m in patternExpr.Matches(val))
                {
                    //Retrieve the field based on the results of the match
                    sTemp = val.Substring(sStart, m.Index - sStart);

                    drRow[nCount] = sTemp;

                    //keep one step ahead in the matching game..

                    sStart = m.Index + 1;

                    //keep track of which field is next
                    nCount++;

                }
                dtTable.Rows.Add(drRow);

                val = NextLine(stream);
            }

            return dsFile;

        }

 *****This function I use to simply read line by line from the text file:

 private static String NextLine(StreamReader stream)
        {
            int stemp = stream.Read();
            String sReturn = "";

            while (stemp != -1 && stemp != '\n')/
            {

                sReturn += (char)stemp;
                stemp = stream.Read();
            }
            return sReturn;
        }

You can use RegEx labels to get the exact match you want. I created a demo for you that takes on line and prints it out to the console, I think this will solve your problem:

            string s = @"Eurex  App: X_RISK     Trader: TTADM  XXX 100     UL: TTADM Workstation: xx.x.x.xx Server: xx.xx.xx.xx";
            Regex r = new Regex(@"(?<Name>\w*)\s*App:\s*(?<App>\w*)\s*Trader:\s*(?<Trader>\w*\s*\w*\s*\w*)\s*UL:\s*(?<UL>\w*)\s*Workstation:\s*(?<Workstation>\w{2}\.\w\.\w\.\w{2})\s*Server:\s*(?<Server>\w{2}\.\w{2}\.\w{2}\.\w{2})");
            Match m = r.Match(s);
            Console.WriteLine(m.Groups["Name"].ToString());
            Console.WriteLine(m.Groups["App"].ToString());
            Console.WriteLine(m.Groups["Trader"].ToString());
            Console.WriteLine(m.Groups["UL"].ToString());
            Console.WriteLine(m.Groups["Workstation"].ToString());
            Console.WriteLine(m.Groups["Server"].ToString());

Thank you so much that solved my issues. That is my first time using regular expressions and it is kinda of hard to grasp from the begining.

thanks 

Yep, regular expressions are not easy to learn, but the effort pays off as you can see in your own example.

I glad I could help. 

 I have one more issue that I am still working on the above code it works, but if I have different input which is coming from a really big file things are getting off hand.

I think it should be something to do with the RegEx string path I don't really know what I am missing.

Here is the input that I am reading as a stream and then I am passing it to a DataTable in order to present it to a grid view and so forth:

And that is my code:

 public DataSet ConvertNew(string sLogFile)
        {
            if (!System.IO.File.Exists(sLogFile))
                return null;//fail file not found

            stream = new StreamReader(sLogFile, true);
            //Create a new data set
            DataSet dsFile = new DataSet("File");

            DataTable dtTable = dsFile.Tables.Add("Data");

            dtTable.Columns.Add("Exchange", typeof(string));
            dtTable.Columns.Add("Application", typeof(string));
            dtTable.Columns.Add("Trader", typeof(string));
            dtTable.Columns.Add("UL", typeof(string));
            dtTable.Columns.Add("Workstation", typeof(string));
            dtTable.Columns.Add("Server", typeof(string));


            Regex r = new Regex(@"(?<Name>\w*)\s*App:\s*(?<App>\w*)\s*Trader:\s*(?<Trader>\w*\s*\w*\s*\w*)\s*UL:\s*(?<UL>\w*)\s*Workstation:\s*(?<Workstation>\w{2}\.\w\.\w\.\w{2})\s*Server:\s*(?<Server>\w{2}\.\w{2}\.\w{2}\.\w{2})");

            // Get the first line of data from the input (log) file.
            val = NextLine(stream);
            //Data row object used to set values
            DataRow drRow;

            while (val != "")//val is empty when the input stream has been read to the end
            {
                //create a new row
                drRow = dtTable.NewRow();

                foreach (Match m in r.Matches(val))
                {
                    //Console.WriteLine(m.Groups["Name"].ToString());
                    //Console.WriteLine(m.Groups["App"].ToString());
                    //Console.WriteLine(m.Groups["Trader"].ToString());
                    //Console.WriteLine(m.Groups["UL"].ToString());
                    //Console.WriteLine(m.Groups["Workstation"].ToString());
                    //Console.WriteLine(m.Groups["Server"].ToString());

                    drRow["Exchange"] = m.Groups["Name"].ToString();
                    drRow["Application"] = m.Groups["App"].ToString();
                    drRow["Trader"] = m.Groups["Trader"].ToString();
                    drRow["UL"] = m.Groups["UL"].ToString();
                    drRow["Workstation"] = m.Groups["Workstation"].ToString();
                    drRow["Server"] = m.Groups["Server"].ToString();

                    dtTable.Rows.Add(drRow);
                }
                val = NextLine(stream);
            }
            return dsFile;
        }
 

I am really stucked with this regex string path

It starts parsing incorrectly  after the 5th line

 After troubleshooting I determined that as soon as it hits dash or underscore it stops working properly.

How can I remove this problem I would really appreciate any input.

Thanks in advance 

\w only works for word characters.

Replace it by [\w-].

Like (?<Name>\w*) will become (?<Name>[\w-]*)

This says to look for 0 or more occurrences of a word character or a dash(-).

Let me know how it works. 

I'll take a look at it and post a little later.

I have to account for the variations of pattern in your string.

Thanks Gabriel your help is very appreciated and helpful 

 Let's try it again. This time I divided the expression for you to understand better:

            string name = @"(?<Name>[\w-]*)\s*";
            string app = @"App:\s*(?<App>[\w-]*)\s*";
            string trader = @"Trader:\s*(?<Trader>([\w-]*\s)+)";
            string ul = @"UL:\s*(?<UL>[\w-]*)\s*";
            string workstation = @"Workstation:\s*(?<Workstation>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s*";
            string server = @"Server:\s*(?<Server>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})";
            Regex r = new Regex(name+app+trader+ul+workstation+server);

Sorry but I had to do it in a hurry because I'm on my way out. If it doesn't work for any reason let me know and I'll correct it.

 No problem, I'm glad I could help.

If you can please mark the post that resolved you problem as Answer.

Thanks a lot.