I would like to save and load my History list filled with History Entry objects. I am trying to do this through Isolated Storage, so that when the user opens and closes the app none of their browsing history is lost. It is saved which can be loaded once the app is clicked. I have had a look around and saw this question on stackoverflow, and I have tried to follow it but came across so errors. Isolated Storage & Saving Multiple Objects.
Here is the code
The HistoryEntry class
public string URL { get; set; }
public string timestamp { get; set; }
public string date { get; set; }
The MainPage code:
using System.Xml.Serialization;
using System.Collections.ObjectModel;
using System.IO;
List<HistoryEntry> urls = new List<HistoryEntry>();
public HistoryEntry selectedHistory;
public MainPage()
{
InitializeComponent();
Deserialize<>(urls, ???);
}
void Browser_Navigated(object sender, System.Windows.Navigation.NavigationEventArgs e)
{
HistoryEntry urlObj = new HistoryEntry();
urlObj.URL = url;
urlObj.timestamp = DateTime.Now.ToString("HH:mm");
urlObj.date = url.Remove(url.LastIndexOf('.'));
urls.Add(urlObj);
textBox1.Text = url;
listBox.ItemsSource = null;
listBox.ItemsSource = urls;
Serialize(urlObj, urls);
}
private static void Serialize(string fileName, object source)
{
var userStore = IsolatedStorageFile.GetUserStoreForApplication();
using (var stream = new IsolatedStorageFileStream(fileName, FileMode.Create, userStore))
{
XmlSerializer serializer = new XmlSerializer(source.GetType());
serializer.Serialize(stream, source);
}
}
public static void Deserialize<T>(ObservableCollection<T> list, string filename)
{
list = new ObservableCollection<T>();
var userStore = IsolatedStorageFile.GetUserStoreForApplication();
if (userStore.FileExists(filename))
{
using (var stream = new IsolatedStorageFileStream(filename, FileMode.Open, userStore))
{
XmlSerializer serializer = new XmlSerializer(list.GetType());
var items = (ObservableCollection<T>)serializer.Deserialize(stream);
foreach (T item in items)
{
list.Add(item);
}
}
}
}
Serialize has some invalid arguments which is the same with when De serialize is called. What are the appropriate values to be sent to the method, and will this successfully save and load the history objects.
Thank you in advance :)
If you need any more details please comment and I will be happy to explain in further detail :)
Did you try this way using MemoryStream which it did work for Win 8 :
To Serialize:
MemoryStream sessionData = new MemoryStream();
DataContractSerializer serializer = new
DataContractSerializer(typeof(ObservableCollection<NewsByTag>));
serializer.WriteObject(sessionData, data);
StorageFile file = await ApplicationData.Current.LocalFolder
.CreateFileAsync(sFileName);
using (Stream fileStream = await file.OpenStreamForWriteAsync())
{
sessionData.Seek(0, SeekOrigin.Begin);
await sessionData.CopyToAsync(fileStream);
await fileStream.FlushAsync();
}
To Deserialize it back:
StorageFile file = await ApplicationData.Current.LocalFolder.
GetFileAsync(sFileName);
using (IInputStream inStream = await file.OpenSequentialReadAsync())
{
DataContractSerializer serializer =
new DataContractSerializer(typeof(ObservableCollection<NewsByTag>));
var data = (ObservableCollection<NewsByTag>)serializer
.ReadObject(inStream.AsStreamForRead());
}
Hope it helps!
Related
I've got one attribute (_XMLPlaylist) that I want to serialize in a XML-file likeshown in the code:
private void btn_Save_Click(object sender, RoutedEventArgs e)
{
_Playlist.Pl_Name = tb_Name.Text.ToString();
_XMLPlaylist.Playlists.Add(_Playlist);
IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication();
using (IsolatedStorageFileStream isoStream = new IsolatedStorageFileStream(StudiCast.Resources.AppResources.Playlists, FileMode.CreateNew, isoStore))
{
using (StreamWriter writer = new StreamWriter(isoStream))
{
var ser = new XmlSerializer(typeof(XMLPlaylist));
ser.Serialize(writer, _XMLPlaylist);
writer.Close();
}
isoStream.Close();
}
}
The Type XMLPlaylist looks as follows:
class XMLPlaylist
{
public XMLPlaylist()
{
Playlists = new List<Playlist>();
}
public List<Playlist> Playlists;
}
And the class Playlist like that:
class Playlist
{
public Playlist()
{
Casts = new List<Cast>();
}
public string Pl_Name;
public List<Cast> Casts;
}
'Cast' owns two strings. In .NET 4 I used the keyword [Serializable] in front of the class's name but there isn't the [Serializable]-attribute anymore.
Need fast Help please!
Edit:
Error at 'var ser = new XmlSerializer(typeof(XMLPlaylist));':
In System.InvalidOperationException an unhandled error of type "System.Xml.Serialization.ni.dll" occurs.
XmlSerializer can serialize only public classes - make your class XMLPlaylist public (also all properties/classes you want to serialize - so Playlist should be public as well).
I have the following method:
public byte[] WriteCsvWithHeaderToMemory<T>(IEnumerable<T> records) where T : class
{
using (var memoryStream = new MemoryStream())
using (var streamWriter = new StreamWriter(memoryStream))
using (var csvWriter = new CsvWriter(streamWriter))
{
csvWriter.WriteRecords<T>(records);
return memoryStream.ToArray();
}
}
Which is being called with a list of objects - eventually from a database, but since something is not working I'm just populating a static collection. The objects being passed are as follows:
using CsvHelper.Configuration;
namespace Application.Models.ViewModels
{
public class Model
{
[CsvField(Name = "Field 1", Ignore = false)]
public string Field1 { get; set; }
[CsvField(Name = "Statistic 1", Ignore = false)]
public int Stat1{ get; set; }
[CsvField(Name = "Statistic 2", Ignore = false)]
public int Stat2{ get; set; }
[CsvField(Name = "Statistic 3", Ignore = false)]
public int Stat3{ get; set; }
[CsvField(Name = "Statistic 4", Ignore = false)]
public int Stat4{ get; set; }
}
}
What I'm trying to do is write a collection to a csv for download in an MVC application. Every time I try to write to the method though, the MemoryStream is coming back with zero length and nothing being passed to it. I've used this before, but for some reason it's just not working - I'm somewhat confused. Can anyone point out to me what I've done wrong here?
Cheers
You already have a using block which is great. That will flush your writer for you. You can just change your code slightly for it to work.
using (var memoryStream = new MemoryStream())
{
using (var streamWriter = new StreamWriter(memoryStream))
using (var csvWriter = new CsvWriter(streamWriter))
{
csvWriter.WriteRecords<T>(records);
} // StreamWriter gets flushed here.
return memoryStream.ToArray();
}
If you turn AutoFlush on, you need to be careful. This will flush after every write. If your stream is a network stream and over the wire, it will be very slow.
Put csvWriter.Flush(); before you return to flush the writer/stream.
EDIT: Per Jack's response. It should be the stream that gets flushed, not the csvWriter. streamWriter.Flush();. Leaving original solution, but adding this correction.
EDIT 2: My preferred answer is: https://stackoverflow.com/a/22997765/1795053 Let the using statements do the heavy lifting for you
Putting all these together (and the comments for corrections), including resetting the memory stream position, the final solution for me was;
using (MemoryStream ms = new MemoryStream())
{
using (TextWriter tw = new StreamWriter(ms))
using (CsvWriter csv = new CsvWriter(tw, CultureInfo.InvariantCulture))
{
csv.WriteRecords(errors); // Converts error records to CSV
tw.Flush(); // flush the buffered text to stream
ms.Seek(0, SeekOrigin.Begin); // reset stream position
Attachment a = new Attachment(ms, "errors.csv"); // Create attachment from the stream
// I sent an email here with the csv attached.
}
}
In case the helps someone else!
There is no flush in csvWriter, the flush is in the streamWriter. When called
csvWriter.Dispose();
it will flush the stream.
Another approach is to set
streamWriter.AutoFlush = true;
which will automatically flush the stream every time.
Here is working example:
void Main()
{
var records = new List<dynamic>{
new { Id = 1, Name = "one" },
new { Id = 2, Name = "two" },
};
Console.WriteLine(records.ToCsv());
}
public static class Extensions {
public static string ToCsv<T>(this IEnumerable<T> collection)
{
using (var memoryStream = new MemoryStream())
{
using (var streamWriter = new StreamWriter(memoryStream))
using (var csvWriter = new CsvWriter(streamWriter))
{
csvWriter.WriteRecords(collection);
} // StreamWriter gets flushed here.
return Encoding.ASCII.GetString(memoryStream.ToArray());
}
}
}
Based on this answer.
using CsvHelper;
public class TwentyFoursStock
{
[Name("sellerSku")]
public string ProductSellerSku { get; set; }
[Name("shippingPoint")]
public string ProductShippingPoint { get; set; }
}
using (var writer = new StreamWriter("file.csv"))
using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
{
csv.WriteRecords(TwentyFoursStock);
}
I have read many codes on this but none happened to solve the problem. first the code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
namespace Serialization
{
class Program
{
static void Main(string[] args)
{
using (MoveSaver objSaver = new MoveSaver(#"C:\1.bin"))
{
MoveAndTime mv1, mv2;
mv1.MoveStruc = "1";
mv1.timeHLd = DateTime.Now;
objSaver.SaveToFile(mv1);
mv2.MoveStruc = "2";
mv2.timeHLd = DateTime.Now;
objSaver.SaveToFile(mv2);
}
using (MoveSaver svrObj = new MoveSaver())
{
MoveAndTime[] MVTobjs = svrObj.DeSerializeObject(#"C:\1.bin");
foreach (MoveAndTime item in MVTobjs)
{
//Do Something
}
}
}
}
public class MoveSaver:IDisposable
{
public void Dispose()
{
if (fs != null)
{
fs.Close();
}
}
FileStream fs;
StreamWriter sw;
public string filename { get; set; }
public MoveSaver(string FileName)
{
this.filename = FileName;
fs = new FileStream(filename, FileMode.OpenOrCreate, FileAccess.ReadWrite);
}
public MoveSaver()
{
}
~MoveSaver()
{
if (fs != null)
{
fs.Close();
}
}
public MoveAndTime[] DeSerializeObject(string filename)
{
MoveAndTime[] objectToSerialize;
Stream stream = File.Open(filename, FileMode.Open);
BinaryFormatter bFormatter = new BinaryFormatter();
objectToSerialize = (MoveAndTime[])bFormatter.Deserialize(stream);
stream.Close();
return objectToSerialize;
}
public bool SaveToFile(MoveAndTime moveTime)
{
try
{
BinaryFormatter bformatter = new BinaryFormatter();
bformatter.Serialize(fs, moveTime);
return true;
}
catch (Exception)
{
return false;
}
}
}
[Serializable]
public struct MoveAndTime
{
public string MoveStruc;
public DateTime timeHLd;
}
}
The code mimics a need for saving all actions of user on the program. to be later shown on that program (say you play cards or so and you want to review :D what has happened). The problem is when DeSerializeObject function is called the line objectToSerialize = (MoveAndTime[])bFormatter.Deserialize(stream); throws an exception (definitely in runtime) that the cast from a single object to array is not valid:
Unable to cast object of type
'Serialization.MoveAndTime' to type
'Serialization.MoveAndTime[]'.
Any idea? Any improvement or total change of approach is appreciated.
You're saving a single MoveAndTime instance to the file, but you're trying to read an array of them.
Please modify your main block like this. I think it achieves what you want.
static void Main(string[] args)
{
using (MoveSaver objSaver = new MoveSaver(#"C:\1.bin"))
{
MoveAndTime[] MVobjects = new MoveAndTime[2];
MoveAndTime mv1, mv2;
mv2 = new MoveAndTime();
mv1 = new MoveAndTime();
mv1.MoveStruc = "1";
mv1.timeHLd = DateTime.Now;
mv2.MoveStruc = "2";
mv2.timeHLd = DateTime.Now;
MVobjects[0] = new MoveAndTime();
MVobjects[0] = mv1;
MVobjects[1] = new MoveAndTime();
MVobjects[1] = mv2;
objSaver.SaveToFile(MVobjects);
}
using (MoveSaver svrObj = new MoveSaver())
{
MoveAndTime[] MVTobjs = svrObj.DeSerializeObject(#"C:\1.bin");
foreach (MoveAndTime item in MVTobjs)
{
//Do Something
Console.WriteLine(item.MoveStruc);
Console.WriteLine(item.timeHLd);
}
}
}
Thanks
Windows Phone 7 App
The Goal of the application is a simple To Do list.
I have a class 'toditem' i add those objects to the Items object.
it seems to me I'm doing something really complicated and most likely no clean or decent code
But i have some serious problems with "IsolatedStorageFile"
public class ToDoItem
{
public string ToDoName { get; set; } // Add controle's enz.
public string ToDoDescription { get; set; }
internal Priority PriortiySelection { get; set; }
...
}
Items class (basicly a wrapper clas so i can acces it)
public class Items
{
public static List<ToDoItem> Itemslist = new List<ToDoItem>();
public static List<ToDoItem> GetList()
static methods here..
}
The code Belows returns the following exceptions :
"Attempt to access the method failed:
System.Io.streamreader..ctor
(System.String)"
and afterwards i get
Operation not permitted on IsolatedStorageFileSTream
if (store.FileExists(#"items.std"))
{
ToDoItem item = new ToDoItem();
try
{
IsolatedStorageFileStream save = new IsolatedStorageFileStream(#"items.std", FileMode.Open, store);
BinaryReader reader = new BinaryReader(save);
}
catch (Exception exc)
{
MessageBox.Show(exc.Message);
}
in public partial class NewToDo : PhoneApplicationPage
i added the following method. wich returns the above exceptions again i only assume that its allowd for some reason or i make some huge mistakes.
private void saveItem(ToDoItem toDoItem)
{
try
{
using (StreamWriter sw = new StreamWriter(store.OpenFile(#"items.std", FileMode.Append)))
{
sw.WriteLine(toDoItem.ToDoName);
sw.WriteLine(toDoItem.ToDoDescription);
sw.WriteLine(toDoItem.PriortiySelection.ToString());
}
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
}
Should u need more information I'm always glad to provide it, I'm currently a student at a Belgium college second year and I'm playing around with windows phone7 apps.
The following will read the contents of a file from isolated storage
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
if (!store.FileExists(VIEW_MODEL_STORAGE_FILE))
{
return result;
}
using (var isfs = new IsolatedStorageFileStream(VIEW_MODEL_STORAGE_FILE, FileMode.Open, store))
{
using (var sr = new StreamReader(isfs))
{
string lineOfData;
while ((lineOfData = sr.ReadLine()) != null)
{
result += lineOfData;
}
}
}
}
The example builds a string of data (result). This is actually a serialized object which is actually a collection of other objects. This can then be deserialized back to the collection. This is probably preferable to what you were trying to do with writing out properties to a file one at a time.
Here's how to write the file:
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
using (var isfs = new IsolatedStorageFileStream(VIEW_MODEL_STORAGE_FILE, FileMode.Create, store))
{
using (var sw = new StreamWriter(isfs))
{
sw.Write(serializedCollectionObject);
sw.Close();
}
}
}
Is it possible you're not disposing all your disposable objects and encountering a problem when you try to access a resource for a second time because it's still in use?
The using statement is a good way to handle this easily, more on that here.
Dispose with Using
A bit more background on the topic here where Jm47 was getting the same error message for this reason.
Problem opening a stream to an isolatedstorage image already the source on an image?
I can serialize a list really easy:
List<String> fieldsToNotCopy =new List<String> {"Iteration Path","Iteration ID"};
fieldsToNotCopy.SerializeObject("FieldsToNotMove.xml");
Now I need a method like this:
List<String> loadedList = new List<String();
loadedList.DeserializeObject("FieldsToNotMove.xml");
Is there such a method? Or am I going to need to create an XML reader and load it in that way?
EDIT: Turns out there is no built in SerialzeObject. I had made one earlier in my project and forgot about it. When I found it I thought it was built in. In case you are curious this is the SerializeObject that I made:
// Save an object out to the disk
public static void SerializeObject<T>(this T toSerialize, String filename)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
TextWriter textWriter = new StreamWriter(filename);
xmlSerializer.Serialize(textWriter, toSerialize);
textWriter.Close();
}
There is no such builtin method as SerializeObject but it's not terribly difficult to code one up.
public void SerializeObject(this List<string> list, string fileName) {
var serializer = new XmlSerializer(typeof(List<string>));
using ( var stream = File.OpenWrite(fileName)) {
serializer.Serialize(stream, list);
}
}
And Deserialize
public void Deserialize(this List<string> list, string fileName) {
var serializer = new XmlSerializer(typeof(List<string>));
using ( var stream = File.OpenRead(fileName) ){
var other = (List<string>)(serializer.Deserialize(stream));
list.Clear();
list.AddRange(other);
}
}
These are my serialize/deserialize extension methods that work quite well
public static class SerializationExtensions
{
public static XElement Serialize(this object source)
{
try
{
var serializer = XmlSerializerFactory.GetSerializerFor(source.GetType());
var xdoc = new XDocument();
using (var writer = xdoc.CreateWriter())
{
serializer.Serialize(writer, source, new XmlSerializerNamespaces(new[] { new XmlQualifiedName("", "") }));
}
return (xdoc.Document != null) ? xdoc.Document.Root : new XElement("Error", "Document Missing");
}
catch (Exception x)
{
return new XElement("Error", x.ToString());
}
}
public static T Deserialize<T>(this XElement source) where T : class
{
try
{
var serializer = XmlSerializerFactory.GetSerializerFor(typeof(T));
return (T)serializer.Deserialize(source.CreateReader());
}
catch //(Exception x)
{
return null;
}
}
}
public static class XmlSerializerFactory
{
private static Dictionary<Type, XmlSerializer> serializers = new Dictionary<Type, XmlSerializer>();
public static XmlSerializer GetSerializerFor(Type typeOfT)
{
if (!serializers.ContainsKey(typeOfT))
{
System.Diagnostics.Debug.WriteLine(string.Format("XmlSerializerFactory.GetSerializerFor(typeof({0}));", typeOfT));
var newSerializer = new XmlSerializer(typeOfT);
serializers.Add(typeOfT, newSerializer);
}
return serializers[typeOfT];
}
}
You just need to define a type for your list and use it instead
public class StringList : List<String> { }
Oh, and you don't NEED the XmlSerializerFactory, it's just there since creating a serializer is slow, and if you use the same one over and over this speeds up your app.
I'm not sure whether this will help you but I have dome something which I believe to be similar to you.
//A list that holds my data
private List<Location> locationCollection = new List<Location>();
public bool Load()
{
//For debug purposes
Console.WriteLine("Loading Data");
XmlSerializer serializer = new XmlSerializer(typeof(List<Location>));
FileStream fs = new FileStream("CurrencyData.xml", FileMode.Open);
locationCollection = (List<Location>)serializer.Deserialize(fs);
fs.Close();
Console.WriteLine("Data Loaded");
return true;
}
This allows me to deserialise all my data back into a List<> but i'd advise putting it in a try - catch block for safety. In fact just looking at this now is going to make me rewrite this in a "using" block too.
I hope this helps.
EDIT:
Apologies, just noticed you're trying to do it a different way but i'll leave my answer there anyway.
I was getting error while deserializing to object. The error was "There is an error in XML document (0, 0)". I have modified the Deserialize function originally written by #JaredPar to resolve this error. It may be useful to someone:
public static void Deserialize(this List<string> list, string fileName)
{
XmlRootAttribute xmlRoot = new XmlRootAttribute();
xmlRoot.ElementName = "YourRootElementName";
xmlRoot.IsNullable = true;
var serializer = new XmlSerializer(typeof(List<string>), xmlRoot);
using (var stream = File.OpenRead(fileName))
{
var other = (List<string>)(serializer.Deserialize(stream));
list.Clear();
list.AddRange(other);
}
}
Create a list of products be serialized
List<string> Products = new List<string>
{
new string("Product 1"),
new string("Product 2"),
new string("Product 3"),
new string("Product 4")
};
Serialization
using (FileStream fs = new FileStream(#"C:\products.txt", FileMode.Create))
{
BinaryFormatter bf = new BinaryFormatter();
bf.Serialize(fs, Products);
}
Deserialization
using (FileStream fs = new FileStream(#"C:\products.txt", FileMode.Open))
{
BinaryFormatter bf = new BinaryFormatter();
var productList = (List<string>)bf.Deserialize(fs);
}