I develops a C# Winform application, it is a client and connect to web service to get data. The data returned by webservice is a DataTable. Client will display it on a DataGridView.
My problem is that: Client will take more time to get all data from server (web service is not local with client). So I must to use a thread to get data. This is my model:
Client create a thread to get data -> thread complete and send event to client -> client display data on datagridview on a form.
However, when user closes the form, user can open this form in another time, and client must get data again. This solution will cause the client slowly.
So, I think about a cached data:
Client <---get/add/edit/delete---> Cached Data ---get/add/edit/delete--->Server (web service)
Please give me some suggestions.
Example: cached data should be developed in another application which is same host with client? Or cached data is running in client.
Please give me some techniques to implement this solution.
If having any examples, please give me.
Thanks.
UPDATE : Hello everyone, maybe you think my problem so far. I only want to cache data in client's lifetime. I think cache data should be stored in memory. And when client want to get data, it will check from cache.
If you're using C# 2.0 and you're prepared to ship System.Web as a dependency, then you can use the ASP.NET cache:
using System.Web;
using System.Web.Caching;
Cache webCache;
webCache = HttpContext.Current.Cache;
// See if there's a cached item already
cachedObject = webCache.Get("MyCacheItem");
if (cachedObject == null)
{
// If there's nothing in the cache, call the web service to get a new item
webServiceResult = new Object();
// Cache the web service result for five minutes
webCache.Add("MyCacheItem", webServiceResult, null, DateTime.Now.AddMinutes(5), Cache.NoSlidingExpiration, System.Web.Caching.CacheItemPriority.Normal, null);
}
else
{
// Item already in the cache - cast it to the right type
webServiceResult = (object)cachedObject;
}
If you're not prepared to ship System.Web, then you might want to take a look at the Enterprise Library Caching block.
If you're on .NET 4.0, however, caching has been pushed into the System.Runtime.Caching namespace. To use this, you'll need to add a reference to System.Runtime.Caching, and then your code will look something like this:
using System.Runtime.Caching;
MemoryCache cache;
object cachedObject;
object webServiceResult;
cache = new MemoryCache("StackOverflow");
cachedObject = cache.Get("MyCacheItem");
if (cachedObject == null)
{
// Call the web service
webServiceResult = new Object();
cache.Add("MyCacheItem", webServiceResult, DateTime.Now.AddMinutes(5));
}
else
{
webServiceResult = (object)cachedObject;
}
All these caches run in-process to the client. Because your data is coming from a web service, as Adam says, you're going to have difficulty determining the freshness of the data - you'll have to make a judgement call on how often the data changes and how long you cache the data for.
Do you have the ability to make changes/add to the webservice?
If you can Sync Services may be an option for you. You can define which tables are syncronised, and all the sync stuff is managed for you.
Check out
http://msdn.microsoft.com/en-us/sync/default.aspx
and shout if you need more information.
You might try the Enterprise Library's Caching Application Block. It's easy to use, stores in memory and, if you ever need to later, it supports adding a backup location for persisting beyond the life of the application (such as to a database, isolated storage, file, etc.) and even encryption too.
Use EntLib 3.1 if you're stuck with .NET 2.0. There's not much new (for caching, at least) in the newer EntLibs aside from better customization support.
Identify which objects you would like to serialize, and cache to isolated storage. Specify the level of data isolation you would like (application level, user level, etc).
Example:
You could create a generic serializer, a very basic sample would look like this:
public class SampleDataSerializer
{
public static void Deserialize<T>(out T data, Stream stm)
{
var xs = new XmlSerializer(typeof(T));
data = (T)xs.Deserialize(stm);
}
public static void Serialize<T>(T data, Stream stm)
{
try
{
var xs = new XmlSerializer(typeof(T));
xs.Serialize(stm, data);
}
catch (Exception e)
{
throw;
}
}
}
Note that you probably should put in some overloads to the Serialize and Deserialize methods to accomodate readers, or any other types you are actually using in your app (e.g., XmlDocuments, etc).
The operation to save to IsolatedStorage can be handled by a utility class (example below):
public class SampleIsolatedStorageManager : IDisposable
{
private string filename;
private string directoryname;
IsolatedStorageFile isf;
public SampleIsolatedStorageManager()
{
filename = string.Empty;
directoryname = string.Empty;
// create an ISF scoped to domain user...
isf = IsolatedStorageFile.GetStore(IsolatedStorageScope.User |
IsolatedStorageScope.Assembly | IsolatedStorageScope.Domain,
typeof(System.Security.Policy.Url), typeof(System.Security.Policy.Url));
}
public void Save<T>(T parm)
{
using (IsolatedStorageFileStream stm = GetStreamByStoredType<T>(FileMode.Create))
{
SampleDataSerializer.Serialize<T>(parm, stm);
}
}
public T Restore<T>() where T : new()
{
try
{
if (GetFileNameByType<T>().Length > 0)
{
T result = new T();
using (IsolatedStorageFileStream stm = GetStreamByStoredType<T>(FileMode.Open))
{
SampleDataSerializer.Deserialize<T>(out result, stm);
}
return result;
}
else
{
return default(T);
}
}
catch
{
try
{
Clear<T>();
}
catch
{
}
return default(T);
}
}
public void Clear<T>()
{
if (isf.GetFileNames(GetFileNameByType<T>()).Length > 0)
{
isf.DeleteFile(GetFileNameByType<T>());
}
}
private string GetFileNameByType<T>()
{
return typeof(T).Name + ".cache";
}
private IsolatedStorageFileStream GetStreamByStoredType<T>(FileMode mode)
{
var stm = new IsolatedStorageFileStream(GetFileNameByType<T>(), mode, isf);
return stm;
}
#region IDisposable Members
public void Dispose()
{
isf.Close();
}
}
Finally, remember to add the following using clauses:
using System.IO;
using System.IO.IsolatedStorage;
using System.Xml.Serialization;
The actual code to use the classes above could look like this:
var myClass = new MyClass();
myClass.name = "something";
using (var mgr = new SampleIsolatedStorageManager())
{
mgr.Save<MyClass>(myClass);
}
This will save the instance you specify to be saved to the isolated storage. To retrieve the instance, simply call:
using (var mgr = new SampleIsolatedStorageManager())
{
mgr.Restore<MyClass>();
}
Note: the sample I've provided only supports one serialized instance per type. I'm not sure if you need more than that. Make whatever modifications you need to support further functionalities.
HTH!
You can serialise the DataTable to file:
http://forums.asp.net/t/1441971.aspx
Your only concern then is deciding when the cache has gone stale. Perhaps timestamp the file?
In our implementation every row in the database has a last-updated timestamp. Every time our client application accesses a table we select the latest last-updated timestamp from the cache and send that value to the server. The server responds with all the rows that have newer timestamps.
Related
I am using AmazonS3Client to Read/Write data to S3 Object Storage. In my code i am creating a new connection everytime while doing operations like Read,List Buckets, Upload, Rename, Delete etc. After deploying my application to production i encountered some performance issues. After going throughh few blogs it was recommended to use single amazonS3 client connection. My code below ->
For every below CRUD operations if you see i am creating a new connection and then disposing it by using block. I am planning to have single connection and use it without using block on every call. Does maintaining a single connection good choice ? I have ~400 users accessing application at the same time.
public ObjectFileInfo(string path)
{
StorageClient = ObjectFileManager.GetClient();
objectFileInfo = ObjectFileManager.getFileInfo(StorageClient, path);
}
public class ObjectFileManager
{
public static Amazon.S3.AmazonS3Client GetClient()
{
AmazonS3Config Config = new AmazonS3Config();
AmazonS3Client StorageClient;
Config.RegionEndpoint = null;
Config.ServiceURL = ConfigurationManager.NGDMSobjECSEndPoint;
Config.AllowAutoRedirect = true;
Config.ForcePathStyle = true;
Config.Timeout = TimeSpan.FromMinutes(30);
StorageClient = new AmazonS3Client(ConfigurationManager.NGDMSobjECSUser, ConfigurationManager.NGDMSobjECSKey, Config);
return StorageClient;
}
public static string[] ListBuckets()
{
ListBucketsResponse Response;
//Creating AmazonS3Client and disposing it in using
using (AmazonS3Client StorageClient = GetClient())
{
Response = StorageClient.ListBuckets();
}
var BucketNames = from Bucket in Response.Buckets select Bucket.BucketName;
return BucketNames.ToArray();
}
public static bool DeleteFile(string keyName)
{
var delRequest = new DeleteObjectRequest
{
BucketName = bucketName,
Key = keyName
};
//Creating AmazonS3Client and disposing it in using
using (AmazonS3Client StorageClient = GetClient())
{
StorageClient.DeleteObject(delRequest);
}
return true;
}
}
Planning to use Singleton as below and removing using block ->
class S3ObjectStorageClient
{
/// <summary>
/// Singleton implementation of Object Storage Client
/// </summary>
private S3ObjectStorageClient()
{
}
public static AmazonS3Client Client
{
get
{
return S3Client.clientInstance;
}
}
/// <summary>
/// Nested private class to ensure Singleton
/// </summary>
private class S3Client
{
static S3Client()
{
}
internal static readonly AmazonS3Client clientInstance = ObjectFileManager.GetClient();
}
}
public ObjectFileInfo(string path)
{
StorageClient = S3ObjectStorageClient.Client; //Singleton
objectFileInfo = ObjectFileManager.getFileInfo(StorageClient, path);
}
public static string[] ListBuckets()
{
ListBucketsResponse Response;
//Singleton and removed using block
AmazonS3Client StorageClient = S3ObjectStorageClient.Client;
Response = StorageClient.ListBuckets();
var BucketNames = from Bucket in Response.Buckets select Bucket.BucketName;
return BucketNames.ToArray();
}
public static bool DeleteFile(string keyName)
{
var delRequest = new DeleteObjectRequest
{
BucketName = bucketName,
Key = keyName
};
//Singleton and removed using block
AmazonS3Client StorageClient = S3ObjectStorageClient.Client;
StorageClient.DeleteObject(delRequest);
return true;
}
}
As one of the authors of the AWS .NET SDK I can give a little more context. Under the cover the AmazonS3Client along with all of the other service clients in the SDK it manages a pool of HttpClients which are the expensive object to create. So when you are creating a new AmazonS3Client the SDK is reusing an HttpClient from a pool the SDK is managing.
If you are using a proxy with proxy credentials then the SDK does have to create a new HttpClient each time a service client is created.
An area where there could be potential performance issues with creating service clients all the time is determining the AWS credentials to use when an AWSCredentials object is not passed into the constructor. That means each service client will have to resolve the credentials which if you are using an assume role profile that could cause a lot of extra calls to perform the assume role. Getting credentials from instance metadata is optimized so that only one thread is refreshing those credentials per process.
Actually you can safely reuse it, according to the docs it is not a bad idea to create and reuse a client. But creating a new client is not very expensive:
The best-known aspect of the AWS SDK for .NET are the various service clients that you can use to interact with AWS. Client objects are thread safe, disposable, and can be reused. (Client objects are inexpensive, so you are not incurring a large overhead by constructing multiple instances, but it’s not a bad idea to create and reuse a client.)
Thus, according to this the performance benefits are probably not that huge. But since there is a small cost to creating a new client I would always reuse the client. That said, according to the docs your code
using (AmazonS3Client StorageClient = GetClient())
{
Response = StorageClient.ListBuckets();
}
is not really bad, but just a bit less efficient than using a singleton. If you think it hurts your performance in a noticable way, best bet is to measure it and if it is really the cause refactor to using a singleton.
Both are valid approach but you'll certainly gain code efficiency using a singleton.
Moreover, dependency injection is promoted by AWS as the right pattern when it comes to using clients. For example, new AWS service CodeGuru profiler highlights multiple client instances as a source of optimization.
See also : https://aws.amazon.com/fr/blogs/developer/working-with-dependency-injection-in-net-standard-inject-your-aws-clients-part-1/
I have some data that needs to be send in SOAP format to a server. This server will immediately acknowledge that it received the messages. After a few hours I get (possibly from another server) a SOAP message that contains information about the processed data.
I read Stackoverflow: How to send SOAP request and receive response. However, the answers are 8 years old. Although they may still work, It may be that there are newer techniques.
And indeed it seems: Microsoft has System.Web.Services.Protocols, with classes like SoapMessage, SoapClientMessage, SoapServerMessage, etc.
Looking at the classes I find a lot of SOAP like classes (headers, extensions, client messages, server messages... Normally the provided examples give me an indication to how these classes work together and how to use them. In the MSDN documents I can only find examples of how to process already existing SOAP messages.
Given some data that needs to be sent, how can I wrap this data somehow in one of these SOAP classes and send this message?
Are these classes meant for this purpose? Or should I stick to the 2011 method where you'd create a SOAP Web request by formatting the XML data in soap format yourself, as the above mentioned Stackoverflow question suggests?
I'm awfully sorry, normally I would write things I have tried. Alas I don't see the relation between the provided SoapMessage classes. I haven't got a clue how to use them.
Addition after comments
I'm using windows server / visual studio (newest versions) / .NET (newest versions) / C# (newest versions).
The communication with the server is mutual authenticated. The certificate that I need to use to communicate with the server, is in PEM (CER / CRT) format. The privated key is RSA. This certificate is issued by a proper CA, the server will also use certificates used by a proper CA. So I don't need to create a new certificate (in fact, it won't be accepted). If needed, I'm willing to convert the certificates using programs like OpenSsl and the like.
I've tried to use Apache TomCat to communicate, but I have the feeling that that's way too much for the task of sending one SOAP message per day and waiting for one answer per day.
Maybe because java is a complete new technique for me, it was difficult for me to see the contents of the received messages. So back to C# and .NET.
I was planning to create a DLL, to be used by a console app. The function would have some data in a stream as input. It would create the soap message, send it, wait for reply that the message was received correctly, and wait (possible several hours) for a new Soap message containing the results of the processed data. To make proper reporting, and cancellation possible, I guess it is best to do this using async-await
If sending the order and waiting for the result can't be done in one application, I'm willing to create a windows service that that listens to the input, but I prefer to keep it simple.
The (virtual) computer will only be used for this task, so no one else will need to listen to port 443. There will be one order message send per day, and one result message per day.
Here is sample C# Console client and server code (they are in the same sample but this is only for demo purpose, of course) that uses HTTPS.
For the client side, we reuse the SoapHttpClientProtocol class, but for the server side, unfortunately, we cannot reuse anything because classes are completely tied to ASP.NET's (IIS) HttpContext class
For the server side, we use HttpListener, so, depending on your configuration, the server side will probably require admin rights to be able to call HttpListener's Prefixes.Add(url).
The code doesn't uses client certificate, but you can add this where I placed // TODO comments
The code assumes there is a certificate associated with the url and port used. If there's not (use netsh http show sslcert to dump all associated certs), you can use the procedure described here to add one: https://stackoverflow.com/a/11457719/403671
using System;
using System.IO;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml;
namespace SoapTests
{
class Program
{
static void Main(string[] args)
{
// code presumes there is an sslcert associated with the url/port below
var url = "https://127.0.0.1:443/";
using (var server = new MyServer(url, MyClient.NamespaceUri))
{
server.Start(); // requests will occur on other threads
using (var client = new MyClient())
{
client.Url = url;
Console.WriteLine(client.SendTextAsync("hello world").Result);
}
}
}
}
[WebServiceBinding(Namespace = NamespaceUri)]
public class MyClient : SoapHttpClientProtocol
{
public const string NamespaceUri = "http://myclient.org/";
public async Task<string> SendTextAsync(string text)
{
// TODO: add client certificates using this.ClientCertificates property
var result = await InvokeAsync(nameof(SendText), new object[] { text }).ConfigureAwait(false);
return result?[0]?.ToString();
}
// using this method is not recommended, as async is preferred
// but we need it with this attribute to make underlying implementation happy
[SoapDocumentMethod]
public string SendText(string text) => SendTextAsync(text).Result;
// this is the new Task-based async model (TAP) wrapping the old Async programming model (APM)
public Task<object[]> InvokeAsync(string methodName, object[] input, object state = null)
{
if (methodName == null)
throw new ArgumentNullException(nameof(methodName));
return Task<object[]>.Factory.FromAsync(
beginMethod: (i, c, o) => BeginInvoke(methodName, i, c, o),
endMethod: EndInvoke,
arg1: input,
state: state);
}
}
// server implementation
public class MyServer : TinySoapServer
{
public MyServer(string url, string namespaceUri)
: base(url)
{
if (namespaceUri == null)
throw new ArgumentNullException(nameof(namespaceUri));
NamespaceUri = namespaceUri;
}
// must be same as client namespace in attribute
public override string NamespaceUri { get; }
protected override bool HandleSoapMethod(XmlDocument outputDocument, XmlElement requestMethodElement, XmlElement responseMethodElement)
{
switch (requestMethodElement.LocalName)
{
case "SendText":
// get the input
var text = requestMethodElement["text", NamespaceUri]?.InnerText;
text += " from server";
AddSoapResult(outputDocument, requestMethodElement, responseMethodElement, text);
return true;
}
return false;
}
}
// simple generic SOAP server
public abstract class TinySoapServer : IDisposable
{
private readonly HttpListener _listener;
protected TinySoapServer(string url)
{
if (url == null)
throw new ArgumentNullException(nameof(url));
_listener = new HttpListener();
_listener.Prefixes.Add(url); // this requires some rights if not used on localhost
}
public abstract string NamespaceUri { get; }
protected abstract bool HandleSoapMethod(XmlDocument outputDocument, XmlElement requestMethodElement, XmlElement responseMethodElement);
public async void Start()
{
_listener.Start();
do
{
var ctx = await _listener.GetContextAsync().ConfigureAwait(false);
ProcessRequest(ctx);
}
while (true);
}
protected virtual void ProcessRequest(HttpListenerContext context)
{
if (context == null)
throw new ArgumentNullException(nameof(context));
// TODO: add a call to context.Request.GetClientCertificate() to validate client cert
using (var stream = context.Response.OutputStream)
{
ProcessSoapRequest(context, stream);
}
}
protected virtual void AddSoapResult(XmlDocument outputDocument, XmlElement requestMethodElement, XmlElement responseMethodElement, string innerText)
{
if (outputDocument == null)
throw new ArgumentNullException(nameof(outputDocument));
if (requestMethodElement == null)
throw new ArgumentNullException(nameof(requestMethodElement));
if (responseMethodElement == null)
throw new ArgumentNullException(nameof(responseMethodElement));
var result = outputDocument.CreateElement(requestMethodElement.LocalName + "Result", NamespaceUri);
responseMethodElement.AppendChild(result);
result.InnerText = innerText ?? string.Empty;
}
protected virtual void ProcessSoapRequest(HttpListenerContext context, Stream outputStream)
{
// parse input
var input = new XmlDocument();
input.Load(context.Request.InputStream);
var ns = new XmlNamespaceManager(new NameTable());
const string soapNsUri = "http://schemas.xmlsoap.org/soap/envelope/";
ns.AddNamespace("soap", soapNsUri);
ns.AddNamespace("x", NamespaceUri);
// prepare output
var output = new XmlDocument();
output.LoadXml("<Envelope xmlns='" + soapNsUri + "'><Body/></Envelope>");
var body = output.SelectSingleNode("//soap:Body", ns);
// get the method name, select the first node in our custom namespace
bool handled = false;
if (input.SelectSingleNode("//x:*", ns) is XmlElement requestElement)
{
var responseElement = output.CreateElement(requestElement.LocalName + "Response", NamespaceUri);
body.AppendChild(responseElement);
if (HandleSoapMethod(output, requestElement, responseElement))
{
context.Response.ContentType = "application/soap+xml; charset=utf-8";
context.Response.StatusCode = (int)HttpStatusCode.OK;
var writer = new XmlTextWriter(outputStream, Encoding.UTF8);
output.WriteTo(writer);
writer.Flush();
handled = true;
}
}
if (!handled)
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
}
}
public void Stop() => _listener.Stop();
public virtual void Dispose() => _listener.Close();
}
}
Personally, I use ServiceStack to create both client and server
https://docs.servicestack.net/soap-support
Or SoapHttpClient nuget
https://github.com/pmorelli92/SoapHttpClient
Or my example from way back when
Is it possible that I can convert simple string to SOAP Message and send it?
The answer depends on what framework or libraries do you plan to use?
The simplest modern answer is to declare a simple class that defines the structure of your message and then serialize it using HttpClient to send it.
However, SOAP is a standard built for description based messaging so the still relevant recommendation is to generate your client code from the wsdl description using a "service reference" then use the generated client object.
I would however recommend, like others have pointed out that you try to move to REST services instead (assuming this is possible).
The code is less complex, the system is far simpler to use and it's a global standard.
Here is a comparison and example of both ...
https://smartbear.com/blog/test-and-monitor/understanding-soap-and-rest-basics/
Good evening; I have an application that has a drop down list; This drop down list is meant to be a list of commonly visited websites which can be altered by the user.
My question is how can I store these values in such a manor that would allow the users to change it.
Example; I as the user, decide i want google to be my first website, and youtube to be my second.
I have considered making a "settings" file however is it practical to put 20+ websites into a settings file and then load them at startup? Or a local database, but this may be overkill for the simple need.
Please point me in the right direction.
Given you have already excluded database (probably for right reasons.. as it may be over kill for a small app), I'd recommend writing the data to a local file.. but not plain text..
But preferably serialized either as XML or JSON.
This approach has at least two benefits -
More complex data can be stored in future.. example - while order can be implicit, it can be made explicit.. or additional data like last time the url was used etc..
Structured data is easier to validate against random corruption.. If it was a plain text file.. It will be much harder to ensure its integrity.
The best would be to use the power of Serializer and Deserializer in c#, which will let you work with the file in an Object Oriented. At the same time you don't need to worry about storing into files etc... etc...
Here is the sample code I quickly wrote for you.
using System;
using System.IO;
using System.Collections;
using System.Xml.Serialization;
namespace ConsoleApplication3
{
public class UrlSerializer
{
private static void Write(string filename)
{
URLCollection urls = new URLCollection();
urls.Add(new Url { Address = "http://www.google.com", Order = 1 });
urls.Add(new Url { Address = "http://www.yahoo.com", Order = 2 });
XmlSerializer x = new XmlSerializer(typeof(URLCollection));
TextWriter writer = new StreamWriter(filename);
x.Serialize(writer, urls);
}
private static URLCollection Read(string filename)
{
var x = new XmlSerializer(typeof(URLCollection));
TextReader reader = new StreamReader(filename);
var urls = (URLCollection)x.Deserialize(reader);
return urls;
}
}
public class URLCollection : ICollection
{
public string CollectionName;
private ArrayList _urls = new ArrayList();
public Url this[int index]
{
get { return (Url)_urls[index]; }
}
public void CopyTo(Array a, int index)
{
_urls.CopyTo(a, index);
}
public int Count
{
get { return _urls.Count; }
}
public object SyncRoot
{
get { return this; }
}
public bool IsSynchronized
{
get { return false; }
}
public IEnumerator GetEnumerator()
{
return _urls.GetEnumerator();
}
public void Add(Url url)
{
if (url == null) throw new ArgumentNullException("url");
_urls.Add(url);
}
}
}
You clearly need some sort of persistence, for which there are a few options:
Local database
- As you have noted, total overkill. You are just storing a list, not relational data
Simple text file
- Pretty easy, but maybe not the most "professional" way. Using XML serialization to this file would allow for complex data types.
Settings file
- Are these preferences really settings? If they are, then this makes sense.
The Registry - This is great for settings you don't want your users to ever manually mess with. Probably not the best option for a significant amount of data though
I would go with number 2. It doesn't sound like you need any fancy encoding or security, so just store everything in a text file. *.ini files tend to meet this description, but you can use any extension you want. A settings file doesn't seem like the right place for this scenario.
I'm coming from a SQL Server background, and experimenting with Redis in .NET using ServiceStack. I don't mean for Redis to be a full replacement for SQL Server, but I just wanted to get a basic idea of how to use it so I could see where we might make good use of it.
I'm struggling with what I think is a pretty basic issue. We have a list of items that are maintained in a couple of different data stores. For the sake of simplicity, assume the definition of the item is basic: an integer id and a string name. I'm trying to do the following:
Store an item
Retrieve an item if we only know its id
Overwrite an existing item if we only know its id
Show all the items for that specific type
And here's some of the code I've put together:
public class DocumentRepositoryRedis
{
private static string DOCUMENT_ID_KEY_BASE = "document::id::";
public IQueryable<Document> GetAllDocuments()
{
IEnumerable<Document> documentsFromRedis;
using (var documents = new RedisClient("localhost").As<Document>())
{
documentsFromRedis = documents.GetAll();
}
return documentsFromRedis.AsQueryable();
}
public Document GetDocument(int id)
{
Document document = null;
using (var redisDocuments = new RedisClient("localhost").As<Document>())
{
var documentKey = GetKeyByID(document.ID);
if (documentKey != null)
document = redisDocuments.GetValue(documentKey);
}
return document;
}
public void SaveDocument(Document document)
{
using (var redisDocuments = new RedisClient("localhost").As<Document>())
{
var documentKey = GetKeyByID(document.ID);
redisDocuments.SetEntry(documentKey, document);
}
}
private string GetKeyByID(int id)
{
return DOCUMENT_ID_KEY_BASE + id.ToString();
}
}
It all seems to work - except for GetAllDocuments. That's returning 0 documents, regardless of how many documents I have stored. What am I doing wrong?
The typed Redis client also gives you access to the non-typed methods - since Redis ultimately doesn't know or care about your object types. So when you use the client.SetEntry() method, it bypasses some of the typed client's features and just stores the object by a key. You'll want to use the client.Store method since it goes ahead and creates a SET in Redis with all the object IDs related to your type. This SET is important because it's what the GetAll method relies on to serve back all the objects to you. The client.Store method does infer the ID automatically so you'll want to play around with it.
You'd change your GetDocument(int id) and SaveDocument(Document document) methods to use the client.GetById(string id) method, and you'd use client.Store(T value) method. You won't need your GetKeyByID() method anymore. I believe your Document object will need an "Id" property for the typed client to infer your object ID.
I have a program that uses clipboard but I want to restore the clipboard to its former state after I am done with it.
This is my code :
IDataObject temp = Clipboard.GetDataObject();
//Some stuff that change Cliboard here
Clipboard.SetText("Hello");
//Some stuff that change Cliboard here
Clipboard.SetDataObject(temp);
But it if I copy a text, and run this code, I get nothing on notepad.
NOTE : I can't use Clipboard.Contains because I want to preserve the Clipboard EXACLY how it was before, even if the user copied a file.
I cannot confirm whether this will work, but I see no reason why you shouldn't be able to back up the data using the longer approach of actually reading the data and restoring it afterwards.
Read here: http://msdn.microsoft.com/en-us/library/system.windows.forms.idataobject.aspx
You would do something like (pseudo-code)
//Backup
var lBackup = new Dictionary<string, object>();
var lDataObject = Clipboard.GetDataObject();
var lFormats = lDataObject.GetFormats(false);
foreach(var lFormat in lFormats)
{
lBackup.Add(lFormat, lDataObject.GetData(lFormat, false));
}
//Set test data
Clipboard.SetText("asd");
//Would be interesting to check the contents of lDataObject here
//Restore data
foreach(var lFormat in lFormats)
{
lDataObject.SetData(lBackup[lFormat]);
}
//This might be unnecessary
Clipboard.SetDataObject(lDataObject);
Is your application exiting after resetting the clipboard?
Assuming it is a Win Form app. (not sure how it works in wpf though)
You could use one of the other overloaded version of Clipboard.SetDataObject
public static void SetDataObject(object data, bool copy)
which preserves the data even after your app exits.
ex: in your case after removing the text content you could call Clipboard.SetDataObject(iDataObject, true);
EDIT:2
I Could source step through Clipboard.cs .NET Frameword 4 / VS 2010.
Download the .NET Framework 4 from here http://referencesource.microsoft.com/netframework.aspx.
Follow the below steps and if it asks for the source (Clipboard.cs) it would be in the Source sub-dir of the installation dir.
EDIT:1
Not sure why the same code doesn't work.
Cannot be a security/permission issue as the code doesn't throw an exception as you say.
There is another approach - source stepping into Framework code - Clipboard.cs
Based on the VS version and .NET framework it may vary ( I couldn't get the source stepping work for .NET 4 as the info is that the symbols with source support haven't yet been released). I'm trying my luck by downloading it manually from here (.NET Version 4)
If you are running VS 2008 and older version of .NET then the below steps should work for you.
More details are here. For .NET Framework 4 - here
This cannot be done. You cannot backup/restore the clipboard without causing unintended consequences.
Please see my post on a similar question. My answer is the one that starts with "It's folly to try to do this".
How do I backup and restore the system clipboard in C#?
Furthermore, I suspect that your motivation for wanting to backup/restore the clipboard is because you want to use it as a crutch to move data, without the user's knowledge or consent. Please read:
http://www.clipboardextender.com/developing-clipboard-aware-programs-for-windows/common-general-clipboard-mistakes
and
http://www.flounder.com/badprogram.htm#clipboard
Lastly, please read and understand this quote:
“Programs should not transfer data into our out of the clipboard without an explicit instruction from the user.” — Charles Petzold, Programming Windows 3.1, Microsoft Press, 1992
I tested the pseudocode from Lukas and found out doesn't work always, this works in all my tests:
// Backup clipboard
lBackup = new Dictionary<string, object>();
lDataObject = Clipboard.GetDataObject();
lFormats = lDataObject.GetFormats(false);
foreach (var lFormat in lFormats)
{
lBackup.Add(lFormat, lDataObject.GetData(lFormat, false));
}
//Set test data
Clipboard.SetText("asd");
//Restore clipboard
lDataObject = new DataObject();
foreach (var lFormat in lFormats)
{
lDataObject.SetData(lFormat, lBackup[lFormat]);
}
//This might be unnecessary
Clipboard.SetDataObject(lDataObject);
I have had success with this.
...to a certain degree.
Where I am currently falling down is trying to copy and restore Bitmaps of varying size.
I can successfully copy and restore a Bitmap of smallish size.
I then tried to do the same for (as the fore-warning Chris Thornton suggested) a gargantuan Excel worksheet with both thousands of cell data, as well as two sets of data on a graph, lying on the same worksheet.
I have found that the data copies and restores without problem. Where it falls down in this instance is allowing the 2-set graph with the worksheet copy.
If any of you have had a problem in copying and restoring Bitmaps, let me suggest what worked for me: when attempting to restore the Clipboard, iterate through the list of formats in reverse order and set each data object that way. (i.e. It seems that a Clipboard must be set in reverse order that it was copied in)
Regarding the case of the gargantuan Excel worksheet and accompanying graph, I also hit another stumbling block: I could not successfully copy the data object whose format was "Meta Data File". That could be the reason why Copy/Restore doesn't work in this case.
I got this far about two weeks ago, and tabled it for more pressing issues.
I wanted to put this out there to let anyone else trying to do the same that it seems like it can be done. (anything can be done in computer science. anything.)
I compiled this code and it seems to work for me. I am persisting via converting to and from json. (Note. It will not do steams so adapt if you need it to)
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
namespace Clipboard
{
class Program
{
static void Main(string[] args)
{
Execute(() =>
{
var backup = Backup();
System.Windows.Forms.Clipboard.SetText("text"); //just to change clipboard
Restore(backup);
});
}
private static void Execute(Action action)
{
var thread = new Thread(() => action());
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
thread.Join();
}
private static List<ClipboardItem> Backup()
{
var backup = new List<ClipboardItem>();
var data = System.Windows.Forms.Clipboard.GetDataObject();
System.Windows.Forms.Clipboard.SetDataObject(data, copy: true); //This seems to be needed to be able to serialize data later.
data = System.Windows.Forms.Clipboard.GetDataObject();
var formats = data.GetFormats(false).ToList();
formats.ForEach(f =>
{
if (data.GetData(f, false) != null && !(data.GetData(f, false) is Stream))
{
backup.Add(new ClipboardItem()
{
Format = f,
ObjectType = data.GetData(f, false).GetType(),
ObjectJson = JsonConvert.SerializeObject(data.GetData(f, false))
});
}
});
return backup;
}
private static void Restore(List<ClipboardItem> backup)
{
var data = new System.Windows.Forms.DataObject();
backup.ForEach(item =>
{
data.SetData(item.Format, JsonConvert.DeserializeObject(item.ObjectJson, item.ObjectType));
});
System.Windows.Forms.Clipboard.SetDataObject(data, copy: true);
}
}
public class ClipboardItem
{
public string Format { get; set; }
public Type ObjectType { get; set; }
public string ObjectJson { get; set; }
}
}