11. Trader - Two nice controls

Formal control if field urlHistory is empty was introduced. If it is empty warning pop up and execution go to label end1:. Probably, much simpler solution is possible to stop execution but I'm not aware of it. Any idea?  Also, if download finished regularly then make BackColor of urlHistory field LightGreen.  


     private void getHistory_Click(object sender, EventArgs e)
        {
            if (urlHistory.Text=="")        // is url entered?
            {MessageBox.Show("URL field is empty.", "No infomation"); // url is not enetred
                goto end1;} // no action. goto end            WebRequest req = WebRequest.Create(urlHistory.Text); // to use WebRequest we need to add "using System.Net;" row
            req.Proxy = null;                                       // i do not use proxy
            string selectedIndices = listIndices.SelectedItem.ToString();   // get selected indice
            selectedIndices=selectedIndices.Replace(":", "-");                      // file name can not contain ":"
            selectedIndices = workingPath + selectedIndices + ".txt";    // make full path,file name and add .txt extension as it is text file
            using (WebResponse res = req.GetResponse())             // get response from internet
            using (Stream s = res.GetResponseStream())              // make a stream
            using (StreamReader sr = new StreamReader(s)) File.WriteAllText(selectedIndices, sr.ReadToEnd()); // save stream to file
            urlHistory.BackColor = Color.LightGreen;  // if file was created make BackColor LightGreen
          //  System.Diagnostics.Process.Start(selectedIndices);    // remove comment and result can be seen in text editor
        end1: ;
        }

Accordingly, we have to reset color to White when new indice is chosen.

 private void listIndices_SelectedIndexChanged(object sender, EventArgs e)
        {
            string part1bloom = "http://www.internet.com/apps/data?pid=webpxta&Securities="; // first part of internet url histroy string
            string part2bloom = "&TimePeriod=5Y&Outfields=HDATE,PR006-H,PR007-H,PR008-H,PR005-H,PR013-H,&rnd=421"; // second part of internet url histroy string
            urlHistory.Text = part1bloom + listIndices.SelectedItem.ToString()+ part2bloom; // construct whole url string
            historyTable.Clear();
            Int16 j = Convert.ToInt16( fillHistoryTableDays.Text);  // convert textbox text to int16
            fillHistoryT(j); // getting data from local disk        // invoke table filling
            urlHistory.BackColor = Color.White;
        }