Jeff Prosise has written an article "Currency
Converter with ASP.NET Web Forms", he pretty much explained how to load XML
data with ASP.NET from the "Rates.xml" file. In this article I have created Currency
Converter Server which can be scheduled to extract the data from third party site
and build the "Rates.xml" dynamically.
CurrencyConverter.dll Component:
"CurrencyConverter.dll" This component will extract the data from PACIFIC Exchange
site using regular expression patterns.
// html for which we are writing this regular
expression pattern
/*
<TD align=middle>ADP</TD>
<TD align=left>Andorran Peseta</TD>
<TD align=right>100.92</TD>
<TD align=right>152.844</TD>
<TD align=right>166.386</TD>
<TD align=right>251.917</TD>
*/
Regex regex = new Regex(@"<td.*?>(.+)</td>+", RegexOptions.IgnoreCase
| RegexOptions.IgnorePatternWhitespace);
MatchCollection matches = regex.Matches(rawHtml);
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for ASP Developers
if (matches.Count > 0)
{
// Get the first match
foreach(Match match in matches)
{
if (match.Success)
{
// Get the second group in the match
Group grp = match.Groups[1];
// return data
Console.WriteLine(grp.Value);
}
}
}
Once we extract the data from the site then we can build "Rates.xml" XML file
using XmlTextWriter class.
XmlTextWriter
writer = new XmlTextWriter(XMLFilePath, System.Text.Encoding.UTF8);
writer.WriteStartDocument(); //Use automatic indentation for readability.
writer.Formatting = Formatting.Indented;
//Write the root element
writer.WriteStartElement("Rates"); //Start an element
writer.WriteStartElement("Rate"); //add sub-elements
writer.WriteElementString("Currency", "British Pound");
writer.WriteElementString("Exchange", "0.635243"); //End the
item element
writer.WriteEndElement(); // end Rate // end the root element
writer.WriteFullEndElement();
//Write the XML to file and close the writer
writer.Flush();
writer.Close();
Test file which will connect to the PACIFIC Exchange site and extract the data
and build "Rates.xml" file.
class BuildXML
{
static void Main()
{ string SupplementaryExchangeRatesActualSiteUrl = "http://pacific.commerce.ubc.ca/xr/rates.html";
Currency cc = new Currency();
cc.ExchangeRatesURL = SupplementaryExchangeRatesActualSiteUrl;
cc.XMLFilePath = "Rates.xml";
cc.Build();
Console.WriteLine(cc.ModuleError.ToString());
}
}
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