SecurityElement.Escape Method

Using System.Security.SecurityElement.Escape() method we can replace the special characters with their Xml equivalent but is there any method which will decode the string to its original form again?

Please help me on this?

using System;
using System.IO;
using System.Security;
using System.Xml;

namespace ReadXMLSalesDataAPI
{
public class PreProcessXML// : IPreProcessXML
{
private string xmlFilename;

/// <param name="_xmlFilename">The filename of the XML document to be converted.</param>
public PreProcessXML(string _xmlFilename)
{
xmlFilename = _xmlFilename;
}

/// <summary>Read the XML file.</summary>
public void ConvertXMLDocument(long linenumber, int lineposition, string exception)
{
try
{
string filepath = xmlFilename;

StreamReader strm;
string strline;
string tempfile = "C:\\Temp.xml";//temporay XML document, for reading from

try
{
File.Copy(filepath, tempfile, true);
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}

StreamWriter strmwriter = new StreamWriter(filepath);
strmwriter.AutoFlush = true;
strm = new StreamReader(tempfile);
int i = 0;

//get the first part of the XML document, upto the invalid character
string line = "";
string errorLine = "";
while ((line = strm.ReadLine()) != null)
{
//get a string containing the correct line
if (i == (linenumber - 1))
{
errorLine = line;
Console.WriteLine("Line num " + i + ", where invalid character is: " + errorLine);
break;
}
else
{
strline = line;
strmwriter.WriteLine(strline);
}

i++;
}
strm.Close();

//check that an invalid characters such as '£' pound sign has not been found
if (!exception.Contains("Invalid character in the given encoding"))
{
//next get the correct line position, which is to be replaced with an XML safe equivalent
string strToReplace = errorLine.Substring(lineposition - 2, 1);
//Console.WriteLine("Char to replace is: " + strToReplace);

//line with the valid character replaced
string newLine = errorLine.Substring(0, lineposition - 2);
// Console.WriteLine("First part is: " + newLine);

//check that a pound sign has not been found
if (SecurityElement.Escape(strToReplace).Trim() != string.Empty)
{
newLine += SecurityElement.Escape(strToReplace);
}
else
{
newLine += strToReplace;
}

//Console.WriteLine("Escape character added is: " + SecurityElement.Escape(strToReplace));
newLine += errorLine.Substring(lineposition - 1);
//Console.WriteLine("Finally Converted line is: " + newLine);

strmwriter.WriteLine(newLine);

strToReplace = SecurityElement.Escape(strToReplace);

//Console.WriteLine("After Conversion, Char to replace with is: " + strToReplace);
}
else
{
strmwriter.WriteLine(errorLine);
}

line = "";
strm = new StreamReader(tempfile);
i = 0;

//get the rest of the XML document after the XML character
while ((line = strm.ReadLine()) != null)
{
//get the rest of the document
if (i >= linenumber)
{
strline = line;
strmwriter.WriteLine(strline);
}

i++;
}

strm.Close();
strm = null;

strmwriter.Flush();
strmwriter.Close();
strmwriter = null;

//finally delete the temporary XML file to free resources, as it is finished with
File.Delete(tempfile);
}
catch(Exception e)
{
Console.WriteLine(e.ToString());
}
}

/// <summary>Attempt to load the XML document. This will determine if the document,
/// contains any errors or not.</summary>
public XmlDocument LoadXMLDoc()
{
XmlDocument xdoc;
int lineNum;
int linePos;

xdoc = new XmlDocument();

try
{
xdoc.Load(xmlFilename);
}
catch (XmlException ex)
{
Console.WriteLine("Exception: " + ex.Message);
lineNum = ex.LineNumber;
linePos = ex.LinePosition;

if (lineNum != 0)
{
if (linePos != 0)
{
ConvertXMLDocument(lineNum, linePos, ex.Message);

LoadXMLDoc();
}
}
}

return (xdoc);
}
}
}

also:

• @
• [
• ]
• "whitespace"

...and a multitude of others...these 5 are helpful but I could just as easily use a switch statement to escape those 5. perhaps a more comprehensive method could be provided....

what's about "/" ?? it's also invalid