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Read XML node using reflection c#

I have this function to read xml values and create an instance of a class.
Is there a way to combine linq and reflection to not specify the properties of the class and create the class with less code lines?
I try to avoid to modify this method if I add or remove some fields to Test_Class
/// <summary>
/// Get the values of a xml node and return a class of type Class_Test
/// </summary>
/// <param name="sXmlFileName">Path to xml file.</param>
/// <param name="sNodeName">Name of node to get values.</param>
/// <returns>Class_Test New class with the values set from XML.</returns>
public static Class_Test Func_ReadXMLNode(string sXmlFileName, string sNodeName)
{
//Load XML
XDocument xml_Document;
Class_Test result;
try
{
xml_Document = XDocument.Load(sXmlFileName);
//Read XML Section
var xmlValues = from r in xml_Document.Descendants(sNodeName)
select new Class_Test
{
sNetworkInterfaceName = Convert.ToString(r.Element("").Value),
iNetworkInterfacePort = Convert.ToInt32(r.Element("").Value),
sCertificateFile = Convert.ToString(r.Element("").Value),
sCertificateName = Convert.ToString(r.Element("").Value),
iKeepAliveSendingTime = Convert.ToInt32(r.Element("").Value),
iMaximumTimeWithoutKeepAlive = Convert.ToInt32(r.Element("").Value),
sSqlServer = Convert.ToString(r.Element("").Value),
sDatabase = Convert.ToString(r.Element("").Value),
iFtpRetries = Convert.ToInt32(r.Element("").Value),
sDetectionFilesDirectory = Convert.ToString(r.Element("").Value),
sImgDirectory = Convert.ToString(r.Element("").Value),
sLocalDirectory = Convert.ToString(r.Element("").Value),
sOffenceDirectory = Convert.ToString(r.Element("").Value),
sTmpDirectory = Convert.ToString(r.Element("").Value)
};
result = xmlValues.FirstOrDefault();
}
catch (IOException Exception1)
{
LogHelper.Func_WriteEventInLogFile(DateTime.Now.ToLocalTime(), enum_EventTypes.Error, "Func_ReadXMLConfig()", "Source = " + Exception1.Source.Replace("'", "''") + ", Message = " + Exception1.Message.Replace("'", "''"));
result = new Class_Test();
}
return result;
}
And this is Class_Text:
/// <summary>
/// Class of operation mode.
/// </summary>
public class Class_OperationMode
{
#region CONFIG_PARAMETERS
/// <summary>
/// Name of the network interface.
/// </summary>
public string sNetworkInterfaceName;
/// <summary>
/// Port of the network interface.
/// </summary>
public int iNetworkInterfacePort;
/// <summary>
/// Path to certificate file.
/// </summary>
public string sCertificateFile;
/// <summary>
/// Name of the certificate.
/// </summary>
public string sCertificateName;
/// <summary>
/// Time to keep alive the connection while sending data.
/// </summary>
public int iKeepAliveSendingTime;
/// <summary>
/// Time before timeout of the connection.
/// </summary>
public int iMaximumTimeWithoutKeepAlive;
/// <summary>
/// Database server instance.
/// </summary>
public string sSqlServer;
/// <summary>
/// Path to .mdf file of database.
/// </summary>
public string sDatabase;
/// <summary>
/// Max retries to try to connect to FTP Server.
/// </summary>
public int iFtpRetries;
/// <summary>
/// Path to detections files directory.
/// </summary>
public string sDetectionFilesDirectory;
/// <summary>
/// Path to images directory.
/// </summary>
public string sImgDirectory;
/// <summary>
/// Path to local directory.
/// </summary>
public string sLocalDirectory;
/// <summary>
/// Path to folder where save and retrieve offences.
/// </summary>
public string sOffenceDirectory;
/// <summary>
/// Path to temp directory.
/// </summary>
public string sTmpDirectory;
#endregion
UPDATE: Thanks to comments, I updated code to:
public static Class_Test Func_ReadXMLNode(string sXmlFileName, string sNodeName){
//Load XML
XDocument xml_Document;
Class_Test result;
try
{
xml_Document = XDocument.Load(sXmlFileName);
//Read XML Section
//Get xml values of descendants
XElement xmlValues = xml_Document.Descendants(sNodeName).FirstOrDefault();
//Create serializer
XmlSerializer serializer = new XmlSerializer(typeof(Class_Test));
//Deserialize
using (XmlReader reader = xmlValues.CreateReader())
{
result = (Class_Test)serializer.Deserialize(reader);
}
}
catch (IOException Exception1)
{
LogHelper.Func_WriteEventInLogFile(DateTime.Now.ToLocalTime(), enum_EventTypes.Error, "Func_ReadXMLConfig()", "Source = " + Exception1.Source.Replace("'", "''") + ", Message = " + Exception1.Message.Replace("'", "''"));
result = new Class_Test();
}
return result;
}
Thanks in advance. Best regards,
Joaquín

I think what youre looking for is serialization/deserialization. Theres lots of useful stuff in .net for handling xml serialization. Ive stolen this example from the docs (link underneath).
XmlSerializer serializer = new
XmlSerializer(typeof(OrderedItem));
// A FileStream is needed to read the XML document.
FileStream fs = new FileStream(filename, FileMode.Open);
XmlReader reader = XmlReader.Create(fs);
// Declare an object variable of the type to be deserialized.
OrderedItem i;
// Use the Deserialize method to restore the object's state.
i = (OrderedItem)serializer.Deserialize(reader);
fs.Close();
From https://msdn.microsoft.com/en-us/library/tz8csy73(v=vs.110).aspx

C# - Odd Null Reference Exception during testing, why does this happen?

This references my last question which appears to have been abandoned. I am experiencing an odd "bug" if you will with C# and MS VS 2015. To reproduce the error, follow the steps:
Open console app project and copy paste code below.
Set a break point here:
First run code past break point, it works! :D
Then run code again but this time STOP at the break point and DRAG the executing statement cursor INTO the if statement from here:
to here:
Hit Continue and an NRE exception is thrown. Why does this happen? Is it just me? What is the technical explination for this?
CODE:
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace testapp
{
class Program
{
static void Main(string[] args)
{
FILECollection randomCollection = new FILECollection();
// Fill with junk test data:
for(int i = 0; i<10; i++)
{
FILE junkfile = new FILE() { fileName = i.ToString(), folderName = i.ToString(), fileHashDigest = new byte[1] };
randomCollection.Add(junkfile);
}
if (true)
{
Console.WriteLine("testing this weird exception issue...");
FILE test;
test = new FILE();
test.fileName = "3";
test.folderName = "3";
test.fileHashDigest = new byte[1];
FILE exists = randomCollection.Where(f => f.fileName == test.fileName &&
f.fileHashDigest.SequenceEqual(test.fileHashDigest)).First();
}
}
}
public class FILE
{
public FILE() { _fileName = "";}
private string _fileName;
public string fileName
{
get
{
if (false)
return this._fileName.ToUpper();
else
return this._fileName;
}
set
{
if (false)
this._fileName = value.ToUpper();
else
this._fileName = value;
}
}
public string folderName { get; set; }
public byte[] fileHashDigest { get; set; }
}
public class FILECollection : IEnumerable<FILE>, ICollection<FILE>
{
private HashSet<FILE> svgHash;
private static List<FILE> PreallocationList;
public string FileName = "N/A";
/// <summary>
/// Default Constructor, will not
/// preallocate memory.
/// </summary>
/// <param name="PreallocationSize"></param>
public FILECollection()
{
this.svgHash = new HashSet<FILE>();
this.svgHash.Clear();
}
/// <summary>
/// Overload Constructor Preallocates
/// memory to be used for the new
/// FILE Collection.
/// </summary>
public FILECollection(int PreallocationSize, string fileName = "N/A", int fileHashDigestSize = 32)
{
FileName = fileName;
PreallocationList = new List<FILE>(PreallocationSize);
for (int i = 0; i <= PreallocationSize; i++)
{
byte[] buffer = new byte[fileHashDigestSize];
FILE preallocationSVG = new FILE()
{
fileName = "",
folderName = "",
fileHashDigest = buffer
};
PreallocationList.Add(preallocationSVG);
}
this.svgHash = new HashSet<FILE>(PreallocationList);
this.svgHash.Clear(); // Capacity remains unchanged until a call to TrimExcess is made.
}
/// <summary>
/// Add an FILE file to
/// the FILE Collection.
/// </summary>
/// <param name="svg"></param>
public void Add(FILE svg)
{
this.svgHash.Add(svg);
}
/// <summary>
/// Removes all elements
/// from the FILE Collection
/// </summary>
public void Clear()
{
svgHash.Clear();
}
/// <summary>
/// Determine if the FILE collection
/// contains the EXACT FILE file, folder,
/// and byte[] sequence. This guarantees
/// that the collection contains the EXACT
/// file you are looking for.
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public bool Contains(FILE item)
{
return svgHash.Any(f => f.fileHashDigest.SequenceEqual(item.fileHashDigest) &&
f.fileName == item.fileName &&
f.folderName == item.folderName);
}
/// <summary>
/// Determine if the FILE collection
/// contains the same file and folder name,
/// byte[] sequence is not compared. The file and folder
/// name may be the same but this does not guarantee the
/// file contents are exactly the same. Use Contains() instead.
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public bool ContainsPartially(FILE item)
{
return svgHash.Any(f => f.fileName == item.fileName &&
f.folderName == item.folderName);
}
/// <summary>
/// Returns the total number
/// of FILE files in the Collection.
/// </summary>
public int Count
{ get { return svgHash.Count(); } }
public bool IsReadOnly
{ get { return true; } }
public void CopyTo(FILE[] array, int arrayIndex)
{
svgHash.CopyTo(array, arrayIndex);
}
public bool Remove(FILE item)
{
return svgHash.Remove(item);
}
public IEnumerator<FILE> GetEnumerator()
{
return svgHash.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return svgHash.GetEnumerator();
}
}
}
I think either I am debugging in a terribly wrong way, or Microsoft should take a look at this. It's like future code is breaking current code...which is impossible!

OK here's my best guess..
First, as I mentioned in the comments, the exception doesn't occur if you comment out the line FILE exists = randomCollection.Where(f => f.fileName == test.fileName && f.fileHashDigest.SequenceEqual(test.fileHashDigest)).First()‌​;
Second, I noticed the same behavior can be reproduced with the following code:
if (true)
{
object o;
o = new object();
Func<bool> m = () => o == null;
}
i.e. the cause seems to be related to the variable being used in a lambda expression. So, looking at the same code snippet above in ILSpy I get the following:
Program.<>c__DisplayClass0_0 <>c__DisplayClass0_ = new Program.<>c__DisplayClass0_0();
<>c__DisplayClass0_.o = new object();
Func<bool> func = new Func<bool>(<>c__DisplayClass0_.<Main>b__0);
so my best guess is that the NullReferenceException refers to <>c__DisplayClass0_ intance being null - and I'm therefore inclined to believe that the stepping through the if(true) actually skipped the first line where <>c__DisplayClass0_ is instantiated

C# Modifying multiple Dictionary Values throws error

I'm using HTML Agility Pack to download some pages, I'm also storing cookie info and login info from a form. The issue I'm having is that I'm doing a GET operation to get the cookie info and form details so on the next step it can login using a username and password, I'm then trying to set the value of the username and password input fields so that I can then post to a login page. The input fields are being stored in a Dictionary<string,string>. I'm able to change one of the dictionary values, but after that I get the error:
"Object reference not set to an instance of an object.".
If I try to change password and then username the username throws the error and vice-versa. This is the code im using:
class Main
{
private void testLogin()
{
BrowserSession b = new BrowserSession();
b.Get("login.html");
b.FormElements["email_address"] = #"email";
b.FormElements["password"] = "password";
string response = b.Post("index.php?main_page=login");
}
}
}
public class BrowserSession
{
private bool _isPost;
private HtmlDocument _htmlDoc;
/// <summary>
/// System.Net.CookieCollection. Provides a collection container for instances of Cookie class
/// </summary>
public CookieCollection Cookies { get; set; }
/// <summary>
/// Provide a key-value-pair collection of form elements
/// </summary>
public FormElementCollection FormElements { get; set; }
/// <summary>
/// Makes a HTTP GET request to the given URL
/// </summary>
public string Get(string url)
{
_isPost = false;
CreateWebRequestObject().Load(url);
return _htmlDoc.DocumentNode.InnerHtml;
}
/// <summary>
/// Makes a HTTP POST request to the given URL
/// </summary>
public string Post(string url)
{
_isPost = true;
CreateWebRequestObject().Load(url, "POST");
return _htmlDoc.DocumentNode.InnerHtml;
}
/// <summary>
/// Creates the HtmlWeb object and initializes all event handlers.
/// </summary>
private HtmlWeb CreateWebRequestObject()
{
HtmlWeb web = new HtmlWeb();
web.UseCookies = true;
web.PreRequest = new HtmlWeb.PreRequestHandler(OnPreRequest);
web.PostResponse = new HtmlWeb.PostResponseHandler(OnAfterResponse);
web.PreHandleDocument = new HtmlWeb.PreHandleDocumentHandler(OnPreHandleDocument);
return web;
}
/// <summary>
/// Event handler for HtmlWeb.PreRequestHandler. Occurs before an HTTP request is executed.
/// </summary>
protected bool OnPreRequest(HttpWebRequest request)
{
AddCookiesTo(request); // Add cookies that were saved from previous requests
if (_isPost) AddPostDataTo(request); // We only need to add post data on a POST request
return true;
}
/// <summary>
/// Event handler for HtmlWeb.PostResponseHandler. Occurs after a HTTP response is received
/// </summary>
protected void OnAfterResponse(HttpWebRequest request, HttpWebResponse response)
{
SaveCookiesFrom(response); // Save cookies for subsequent requests
}
/// <summary>
/// Event handler for HtmlWeb.PreHandleDocumentHandler. Occurs before a HTML document is handled
/// </summary>
protected void OnPreHandleDocument(HtmlDocument document)
{
SaveHtmlDocument(document);
}
/// <summary>
/// Assembles the Post data and attaches to the request object
/// </summary>
private void AddPostDataTo(HttpWebRequest request)
{
string payload = FormElements.AssemblePostPayload();
byte[] buff = Encoding.UTF8.GetBytes(payload.ToCharArray());
request.ContentLength = buff.Length;
request.ContentType = "application/x-www-form-urlencoded";
System.IO.Stream reqStream = request.GetRequestStream();
reqStream.Write(buff, 0, buff.Length);
}
/// <summary>
/// Add cookies to the request object
/// </summary>
private void AddCookiesTo(HttpWebRequest request)
{
if (Cookies != null && Cookies.Count > 0)
{
request.CookieContainer.Add(Cookies);
}
}
/// <summary>
/// Saves cookies from the response object to the local CookieCollection object
/// </summary>
private void SaveCookiesFrom(HttpWebResponse response)
{
if (response.Cookies.Count > 0)
{
if (Cookies == null) Cookies = new CookieCollection();
Cookies.Add(response.Cookies);
}
}
/// <summary>
/// Saves the form elements collection by parsing the HTML document
/// </summary>
private void SaveHtmlDocument(HtmlDocument document)
{
_htmlDoc = document;
FormElements = new FormElementCollection(_htmlDoc);
}
}
public class FormElementCollection : Dictionary<string, string>
{
/// <summary>
/// Constructor. Parses the HtmlDocument to get all form input elements.
/// </summary>
public FormElementCollection(HtmlDocument htmlDoc)
{
var inputs = htmlDoc.DocumentNode.SelectSingleNode("//div[#id = 'loginDefault']").Descendants("input");
foreach (var element in inputs)
{
string name = element.GetAttributeValue("name", "undefined");
string value = element.GetAttributeValue("value", "");
if (!name.Equals("undefined")) { Add(name, value); }
}
}
/// <summary>
/// Assembles all form elements and values to POST. Also html encodes the values.
/// </summary>
public string AssemblePostPayload()
{
StringBuilder sb = new StringBuilder();
foreach (var element in this)
{
string value = HttpUtility.UrlEncode(element.Value);
sb.Append("&" + element.Key + "=" + value);
}
return sb.ToString().Substring(1);
}
}
Any help would be much appreciated.

While debugging put a break point after calling the b constractor.
You ll find the FormElements property is Null.
You need to inialize it in BrowserSession constractor.

write list of objects to a file

I've got a class salesman in the following format:
class salesman
{
public string name, address, email;
public int sales;
}
I've got another class where the user inputs name, address, email and sales.
This input is then added to a list
List<salesman> salesmanList = new List<salesman>();
After the user has input as many salesman to the list as they like, they have the option to save the list to a file of their choice (which I can limit to .xml or .txt(which ever is more appropriate)).
How would I add this list to the file?
Also this file needs to be re-read back into a list if the user wishes to later view the records.

Something like this would work. this uses a binary format (the fastest for loading) but the same code would apply to xml with a different serializer.
using System.IO;
[Serializable]
class salesman
{
public string name, address, email;
public int sales;
}
class Program
{
static void Main(string[] args)
{
List<salesman> salesmanList = new List<salesman>();
string dir = #"c:\temp";
string serializationFile = Path.Combine(dir, "salesmen.bin");
//serialize
using (Stream stream = File.Open(serializationFile, FileMode.Create))
{
var bformatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
bformatter.Serialize(stream, salesmanList);
}
//deserialize
using (Stream stream = File.Open(serializationFile, FileMode.Open))
{
var bformatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
List<salesman> salesman = (List<salesman>)bformatter.Deserialize(stream);
}
}
}

I just wrote a blog post on saving an object's data to Binary, XML, or Json; well writing an object or list of objects to a file that is. Here are the functions to do it in the various formats. See my blog post for more details.
Binary
/// <summary>
/// Writes the given object instance to a binary file.
/// <para>Object type (and all child types) must be decorated with the [Serializable] attribute.</para>
/// <para>To prevent a variable from being serialized, decorate it with the [NonSerialized] attribute; cannot be applied to properties.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the XML file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the XML file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToBinaryFile<T>(string filePath, T objectToWrite, bool append = false)
{
using (Stream stream = File.Open(filePath, append ? FileMode.Append : FileMode.Create))
{
var binaryFormatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
binaryFormatter.Serialize(stream, objectToWrite);
}
}
/// <summary>
/// Reads an object instance from a binary file.
/// </summary>
/// <typeparam name="T">The type of object to read from the XML.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the binary file.</returns>
public static T ReadFromBinaryFile<T>(string filePath)
{
using (Stream stream = File.Open(filePath, FileMode.Open))
{
var binaryFormatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
return (T)binaryFormatter.Deserialize(stream);
}
}
XML
Requires the System.Xml assembly to be included in your project.
/// <summary>
/// Writes the given object instance to an XML file.
/// <para>Only Public properties and variables will be written to the file. These can be any type though, even other classes.</para>
/// <para>If there are public properties/variables that you do not want written to the file, decorate them with the [XmlIgnore] attribute.</para>
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToXmlFile<T>(string filePath, T objectToWrite, bool append = false) where T : new()
{
TextWriter writer = null;
try
{
var serializer = new XmlSerializer(typeof(T));
writer = new StreamWriter(filePath, append);
serializer.Serialize(writer, objectToWrite);
}
finally
{
if (writer != null)
writer.Close();
}
}
/// <summary>
/// Reads an object instance from an XML file.
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object to read from the file.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the XML file.</returns>
public static T ReadFromXmlFile<T>(string filePath) where T : new()
{
TextReader reader = null;
try
{
var serializer = new XmlSerializer(typeof(T));
reader = new StreamReader(filePath);
return (T)serializer.Deserialize(reader);
}
finally
{
if (reader != null)
reader.Close();
}
}
Json
You must include a reference to Newtonsoft.Json assembly, which can be obtained from the Json.NET NuGet Package.
/// <summary>
/// Writes the given object instance to a Json file.
/// <para>Object type must have a parameterless constructor.</para>
/// <para>Only Public properties and variables will be written to the file. These can be any type though, even other classes.</para>
/// <para>If there are public properties/variables that you do not want written to the file, decorate them with the [JsonIgnore] attribute.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToJsonFile<T>(string filePath, T objectToWrite, bool append = false) where T : new()
{
TextWriter writer = null;
try
{
var contentsToWriteToFile = JsonConvert.SerializeObject(objectToWrite);
writer = new StreamWriter(filePath, append);
writer.Write(contentsToWriteToFile);
}
finally
{
if (writer != null)
writer.Close();
}
}
/// <summary>
/// Reads an object instance from an Json file.
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object to read from the file.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the Json file.</returns>
public static T ReadFromJsonFile<T>(string filePath) where T : new()
{
TextReader reader = null;
try
{
reader = new StreamReader(filePath);
var fileContents = reader.ReadToEnd();
return JsonConvert.DeserializeObject<T>(fileContents);
}
finally
{
if (reader != null)
reader.Close();
}
}
Example
// Write the list of salesman objects to file.
WriteToXmlFile<List<salesman>>("C:\salesmen.txt", salesmanList);
// Read the list of salesman objects from the file back into a variable.
List<salesman> salesmanList = ReadFromXmlFile<List<salesman>>("C:\salesmen.txt");

If you want to use JSON then using Json.NET is usually the best way to go.
If for some reason you are unable to use Json.NET you can use the built in JSON support found in .NET.
You will need to include the following using statement and add a reference for System.Web.Extentsions.
using System.Web.Script.Serialization;
Then you would use these to Serialize and Deserialize your object.
//Deserialize JSON to your Object
YourObject obj = new JavaScriptSerializer().Deserialize<YourObject>("File Contents");
//Serialize your object to JSON
string sJSON = new JavaScriptSerializer().Serialize(YourObject);
https://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer_methods(v=vs.110).aspx

If you want xml serialization, you can use the built-in serializer. To achieve this, add [Serializable] flag to the class:
[Serializable()]
class salesman
{
public string name, address, email;
public int sales;
}
Then, you could override the "ToString()" method which converts the data into xml string:
public override string ToString()
{
string sData = "";
using (MemoryStream oStream = new MemoryStream())
{
XmlSerializer oSerializer = new XmlSerializer(this.GetType());
oSerializer.Serialize(oStream, this);
oStream.Position = 0;
sData = Encoding.UTF8.GetString(oStream.ToArray());
}
return sData;
}
Then just create a method that writes this.ToString() into a file.
UPDATE
The mentioned above will serialize single entry as xml. If you need the whole list to be serialized, the idea would be a bit different. In this case you'd employ the fact that lists are serializable if their contents are serializable and use the serialization in some outer class.
Example code:
[Serializable()]
class salesman
{
public string name, address, email;
public int sales;
}
class salesmenCollection
{
List<salesman> salesmanList;
public void SaveTo(string path){
System.IO.File.WriteAllText (path, this.ToString());
}
public override string ToString()
{
string sData = "";
using (MemoryStream oStream = new MemoryStream())
{
XmlSerializer oSerializer = new XmlSerializer(this.GetType());
oSerializer.Serialize(oStream, this);
oStream.Position = 0;
sData = Encoding.UTF8.GetString(oStream.ToArray());
}
return sData;
}
}

Why can I still write to session when SessionStateBehavior.ReadOnly is set on a controller and should I care?

I have a number of controllers with SessionStateBehavior.ReadOnly set on them to enable parallel processing of multiple ajax requests.
But I have noticed that this doesn't stop me from writing to session (unlike SessionStateBehavior.Disabled which throws an exception).
My application uses Microsoft Charting and the chart and image map are generated in response to an ajax request with the chart being stored in session until the image markup is rendered by the browser at which point the image src triggers the browser to request the chart image which is retrieved from session. So there are no issues here with attempting to read from session before its been written.
Everything works fine, I have multiple ajax requests being processed in parallel and my charts are being returned correctly so does it matter that I have declared SessionStateBehavior.ReadOnly when I am writing to session?
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web.Mvc;
using System.Web.UI.DataVisualization.Charting;
using Mdl.Rcm.Web.Areas.Dashboards.Models;
using Mdl.Web.Security;
using Mdl.Persistence.UoW;
using Mdl.Rcm.Business.Dashboards;
using Mdl.Rcm.Business.Dashboards.Models;
using Mdl.Rcm.Web.Areas.Dashboards.Charts;
using Mdl.Rcm.Web.Areas.Dashboards.Charts.OrganisationConnectionsByRole;
using Mdl.Web.Mvc;
namespace Mdl.Rcm.Web.Areas.Dashboards.Controllers
{
/// <summary>
/// Controller for the Organisation Connections By Role chart.
/// </summary>
[SessionState(System.Web.SessionState.SessionStateBehavior.ReadOnly)]
[RedirectingAuthorize(Roles = "Dashboards")]
[Area(IsSiteRoot = false)]
public class ChartOrganisationConnectionsByRoleController : Controller
{
private readonly IRelationshipAndRiskService relationshipAndRiskService;
private readonly IConfigurationService configurationService;
private readonly IOrganisationConnectionsByRoleChartBuilder chartBuilder;
private readonly IListService listService;
private BarConfiguration barConfiguration;
private const string TempDataKey = "OrganisationConnectionsByRoleData";
public ChartOrganisationConnectionsByRoleController(IOrganisationConnectionsByRoleChart organisationConnectionsByRoleChart, IRelationshipAndRiskService relationshipAndRiskService, IConfigurationService configurationService, IOrganisationConnectionsByRoleChartBuilder chartBuilder, IListService listService)
{
this.relationshipAndRiskService = relationshipAndRiskService;
this.configurationService = configurationService;
this.chartBuilder = chartBuilder;
this.listService = listService;
}
/// <summary>
/// Standard Organisation Connections by Role component loader
/// </summary>
/// <param name="listId">The list id.</param>
/// <param name="degree">The active degree.</param>
/// <param name="barIndex">Index of the active bar.</param>
/// <returns></returns>
[HandleAjaxError]
public ActionResult Load(int listId, int degree, int barIndex)
{
using (UnitOfWork.Start("Analysis"))
{
// Get the data
var relationshipPlanningData = GetChartDataForInitialLoadParentComponent(listId);
var connectionsFound = relationshipPlanningData.SeriesModels.Count > 0;
var listName = listService.GetListName(listId).Name;
var information = new InformationModel(degree, true) { ConnectionsFound = connectionsFound, NumberOfOrganisationsInList = relationshipPlanningData.TotalNumberOfOrganisations, ListName = listName };
return PartialView("OrganisationConnectionsByRoleComponent", new OrganisationConnectionsByRoleComponentModel { ListId = listId, ActiveDegree = degree, ActiveBarIndex = barIndex, BarConfiguration = configurationService.GetBarConfiguration(), ConnectionsFound = connectionsFound, Information = information});
}
}
/// <summary>
/// Creates the Connections by Role chart and stores it in Session then returns the chart map.
/// The chart image map is always created first, the chart is created as part of the process of creating the map.
/// </summary>
/// <returns></returns>
public ActionResult Chart(Guid chartId, int listId)
{
using (UnitOfWork.Start("Analysis"))
{
barConfiguration = configurationService.GetBarConfiguration();
var relationshipPlanningData = GetChartDataForInitialLoadChart();
if (relationshipPlanningData.SeriesModels.Count == 0)
{
return PartialView("InfoMessage", "No connections found");
}
// Set up the chart
return GenerateChart(relationshipPlanningData, listId, chartId);
}
}
private ActionResult GenerateChart(OrganisationConnectionsByRoleData relationshipPlanningData, int listId, Guid chartId)
{
var chartAndXPoints = chartBuilder.BuildChart(2, relationshipPlanningData, barConfiguration, SetActiveBarIndex(-1), listId);
// Store the chart in session for retrieval by the browser as the src on an image tag.
ChartSession.GenerateChartToSession(chartId, chartAndXPoints.Chart, Session);
// Get y data for use client side
var yPointsDataView = GetYPointsDataView(relationshipPlanningData);
// Get x co-ordinates for use client side. Must be done after the chart has been generated to session.
var xPointsView = GetXPointsView(chartAndXPoints.XPoints);
// Render the image tag and image map
return this.Chart(chartAndXPoints.Chart, xPointsView + yPointsDataView, chartId, "ConnectionsByRoleImage");
}
/// <summary>
/// Gets the chart data for use by the main component.
/// </summary>
/// <param name="listId">The list id.</param>
/// <returns></returns>
private OrganisationConnectionsByRoleData GetChartDataForInitialLoadParentComponent(int listId)
{
// This is the call from the load action so get the data and store it for use by the chart action to save the performance hit
var data = relationshipAndRiskService.GetOrganisationConnectionsByRoleChartData(listId);
TempData[TempDataKey] = data;
return data;
}
/// <summary>
/// Gets the chart data for use by the main component chart.
/// </summary>
/// <returns></returns>
private OrganisationConnectionsByRoleData GetChartDataForInitialLoadChart()
{
// This call is from the chart action so use the data that was retreived on the load action
return (OrganisationConnectionsByRoleData)TempData[TempDataKey];
}
/// <summary>
/// Return the Connections By Role chart from session.
/// </summary>
/// <returns></returns>
public ActionResult ConnectionsByRoleImage(Guid chartId)
{
var chart = ChartSession.GetChartFromSession(chartId, Session);
return File(chart, "image");
}
/// <summary>
/// Return the Connections By Role chart from session.
/// </summary>
/// <param name="listId">The list id.</param>
/// <param name="degree">The active degree.</param>
/// <param name="barIndex">Index of the active bar.</param>
/// <returns></returns>
public ActionResult ConnectionsByRoleActive(int listId, int degree, int barIndex)
{
using (UnitOfWork.Start("Analysis"))
{
barConfiguration = configurationService.GetBarConfiguration();
// Get the data
var relationshipPlanningData = relationshipAndRiskService.GetOrganisationConnectionsByRoleChartData(listId);
if (relationshipPlanningData.SeriesModels.Count == 0)
{
return PartialView("InfoMessage", "No connections found");
}
// Set up the chart
var chartAndXPoints = chartBuilder.BuildChart(SetActiveDegree(degree), relationshipPlanningData, barConfiguration, SetActiveBarIndex(-1), listId);
var ms = new MemoryStream();
chartAndXPoints.Chart.SaveImage(ms, ChartImageFormat.Png);
return File(ms.ToArray(), "image");
}
}
/// <summary>
/// Gets the graph X points and render them as a javascript object for use by the view.
/// </summary>
/// <param name="xPoints">The x points.</param>
/// <returns></returns>
private string GetXPointsView(List<float> xPoints)
{
var model = new XPointsModel
{
ChartName = "Connections By Role",
Points = xPoints
};
return this.ViewAsString("XPoints", model);
}
/// <summary>
/// Gets the Y points data and render them as a javascript object for use by the view.
/// </summary>
/// <param name="relationshipPlanningData">The relationship planning data.</param>
/// <returns></returns>
private string GetYPointsDataView(OrganisationConnectionsByRoleData relationshipPlanningData)
{
var degree1DataPoints = relationshipPlanningData.SeriesModels[0].DataPoints.Select(p => p.Y).ToList();
var degree2DataPoints = relationshipPlanningData.SeriesModels[1].DataPoints.Select(p => p.Y).ToList();
var model = new YPointsDegree1And2Model
{
ChartName = "Connections By Role",
Degree1Data = degree1DataPoints,
Degree2Data = degree2DataPoints
};
return this.ViewAsString("YPointsDegree1And2", model);
}
private int SetActiveBarIndex(int barIndex)
{
if (barIndex == -1)
{
barIndex = barConfiguration.Bars.First(b => b.IsDefaultActive).Index;
}
return barIndex;
}
private static int SetActiveDegree(int degree)
{
if (degree == -1)
{
degree = 2;
}
return degree;
}
}
}
public class ChartSession
{
public static byte[] GetChartFromSession(Guid chartId, HttpSessionStateBase session)
{
// Get the chart from session
var data = session[chartId.ToString()] as byte[];
// Clear the session
session[chartId.ToString()] = null;
return data;
}
public static void GenerateChartToSession(Guid chartId, Chart chart, HttpSessionStateBase session)
{
var ms = new MemoryStream();
chart.SaveImage(ms, ChartImageFormat.Png);
session[chartId.ToString()] = ms.ToArray();
}

SessionStateBehavior only tells ASP.NET what locks to put on the Session
See this question: Controller SessionStateBehavior is ReadOnly and I can update Session Variable