Search Results

Search found 2648 results on 106 pages for 'jon snow'.

Page 56/106 | < Previous Page | 52 53 54 55 56 57 58 59 60 61 62 63  | Next Page >

  • JSF a4j:commandButton not working when 'disabled' is set

    - by Jon
    Hello, When I include a 'disabled' attribute on an a4j:commandButton, the button's action is not performed. Taking the 'disabled' attribute out causes it to work properly. I am not doing any special validation (that I'm aware of) and am not seeing any validation error messages. Here is part of my page: <t:dataTable id="myTable" var="region" value="#{MyPageBackingBean.regions}" width="100%"> ... <a4j:commandButton value="Update" action="#{region.doUpdate}" oncomplete="alert('done');" disabled="#{!empty region && region.messageEmpty}" immediate="true"/> ... </t:dataTable> Any ideas? Thanks! Edit: I tried setting preserveDataModel="true" on the t:dataTable to no avail. I also made a test having an a4j:commandButton and text box with no data table, but the backing bean action is still not being fired: <h:form> <a4j:region> <a4j:outputPanel id="testregion"> <h:messages id="messages"/> <a4j:status> <f:facet name="start"> <h:graphicImage value="/images/progress_indicator.gif"/> </f:facet> </a4j:status> <h:inputTextarea rows="5" value="#{MyPageBackingBean.myValue}" style="width:100%; border: 1px solid #99CCFF;"> <a4j:support event="onkeyup" reRender="testregion" eventsQueue="messageModificationQueue" ignoreDupResponses="true" requestDelay="500"/> </h:inputTextarea> <a4j:commandButton id="doDelete" value="Delete" action="#{MyPageBackingBean.dummy}" reRender="testregion" disabled="#{empty MyPageBackingBean.myValue}"/> <h:outputText value="#{MyPageBackingBean.myValue}"/> </a4j:outputPanel> </a4j:region> </h:form> Here is the new backing bean code used for testing: private String m_myValue = null; public String getMyValue() { return m_myValue; } public void setMyValue(String value) { m_myValue = value; } private String mystr2 = null; public String dummy() { mystr2 = "hello"; return null; } Thanks!

    Read the article

  • jQuery monitoring form field created by AJAX query

    - by Jon Rhoades
    Preface: I am sure this is incredibly simple, but I have searched this site & the jQuery site and can't figure out the right search term to get an answer - please excuse my ignorance! I am adding additional form fields using jQuery's ajax function and need to then apply additional ajax functions to those fields but can't seem to get jQuery to monitor these on the fly form fields. How can I get jQuery to use these new fields? $(document).ready(function() { $('#formField').hide(); $('.lnk').click(function() { var t = this.id; $('#formField').show(400); $('#form').load('loader.php?val=' + t); }); //This works fine if the field is already present var name = $('#name'); var email = $('#email'); $('#uid').keyup(function () { var t = this; if (this.value != this.lastValue) { if (this.timer) clearTimeout(this.timer); this.timer = setTimeout(function () { $.ajax({ url: 'loader.php', data: 'action=getUser&uid=' + t.value, type: 'get', success: function (j) { va = j.split("|"); displayname = va[1]; mail = va[2]; name.val(displayname); email.val(mail); } }); }, 200); this.lastValue = this.value; } }); }); So if the is present in the basic html page the function works, but if it arrives by the $.load function it doesn't - presumably because $(document).ready has already started. I did try: $(document).ready(function() { $('#formField').hide(); $('.lnk').click(function() { var t = this.id; $('#formField').show(400); $('#form').load('loader.php?val=' + t); prepUid(); }); }); function prepUid(){ var name = $('#name'); var email = $('#email'); $('#uid').keyup(function () { snip........... But it didn't seem to work...

    Read the article

  • ExtAsp or Coolite - ASP.NET wrappers around ExtJs

    - by Jon
    Hi, We are a small Microsoft shop looking into ExtJs and like the rapid building of complex and structured UIs that can be achieved with the toolkit. However we have been experimenting with ExtAsp.NET (CodePlex) which is an opensource layer of ASP.NET code which wraps around the ExtJs framework. We have also noticed the Coolite framework which looks good too and does the same thing. We have 2 options, either we purchase the ExtJs license which will be required if we use ExtAsp, or we purchase the Coolite kit which includes the ExtJs license. It looks like Coolite is actually it little cheaper than the ExtJs for some reason?? However, is it a little more risky as regards upgrade path if the Coolite framework becomes unsupported, whereas ExtAsp as an open source solution will have community backing? Just looking to make the right step.

    Read the article

  • Getting a .Net remoting service accessible with IP v6 and IP v4

    - by jon.ediger
    My company has an existing .Net Remoting service that listens on a port, fronting interfaces used by external systems. This all works great with IP v4 based communications. However, this service now needs to support both IP v4 communications and IP v6 communications. I have found info that the system.runtime.remoting section of the app.config should include two channels as follows: <channel ref="tcp" name="tcp6" port="9000" bindTo="[::]" /> <channel ref="tcp" name="tcp4" port="9000" bindTo="0.0.0.0" /> I've tried this. For communications to this service and a direct response back, this works great. Some of the communications instead return a stream back, either for uploading or downloading large files. These calls fail with the an ArgumentException: IPv4 address 0.0.0.0 and IPv6 address ::0 are unspecified addresses that cannot be used as a target address. Parameter name: hostNameOrAddress How should these config values be modified so that the client will know how to communicate back to the .Net remoting service?

    Read the article

  • Web application creation in IIS7 via MS.Web.Admin

    - by Jon Ownbey
    I am attempting to create seperate workflow instances as applications in IIS7 using the Microsoft.Web.Administration dll. When it attempts to add the Application to the Site ApplicationsCollection I get a COM error: "Invalid application path\r\n" using (ServerManager manager = new ServerManager()) { var site = manager.Sites.Where(x => x.Name == Properties.Settings.Default.WorkflowWebsiteName).Single(); StringBuilder stringBuilder = new StringBuilder() .Append(m_workflowDefinition.AccountId) .Append("/") .Append(m_workflowDefinition.WorkflowDefinitionId) .Append("/") .Append(m_workflowDefinition.Version) .Append("/"); string virtualPath = stringBuilder.ToString(); string physicalPath = Properties.Settings.Default.ApplicationPoolString + virtualPath.Replace("/", "\\"); if (!Directory.Exists(physicalPath)) Directory.CreateDirectory(physicalPath); //Create the workflow service definition file using (StreamWriter writer = new StreamWriter(Path.Combine(physicalPath, m_workflowDefinition.WorkflowName + WORKFLOW_FILE_EXTENSION))) { writer.Write(m_workflowDefinition.Definition); } //Copy dependencies string dependencyPath = m_workflowDefinition.DependenciesPath; CopyAll(new DirectoryInfo(dependencyPath), new DirectoryInfo(physicalPath)); //Create a new IIS application for the workflow var apps = site.Applications.Where(x => x.Path == virtualPath); if (apps.Count() > 0) { site.Applications.Remove(apps.Single()); } Application app = site.Applications.Add(virtualPath, physicalPath); app.ApplicationPoolName = "Workflow AppPool"; app.EnabledProtocols = PROTOCOLS; manager.CommitChanges(); } The value assigned to virtualPath is like: "something/something/something" and for physicalPath it is "c:\inetpub\wwwroot\Workflow\something\something\something". Any ideas? Any help is greatly appreciated.

    Read the article

  • FileSystemWatcher vs Polling to watch for changes

    - by Jon Tackabury
    I need to setup an application that watches for files being created in a folder (locally or on a network drive) and I was wondering if anyone has any thoughts on whether the FileSystemWatcher or polling on a timer would be the best option. I have used both methods in the past, but not extensively. Have you run into any issues (performance, reliability... etc) with either method? I know there isn't a "right way" to do this, I'm just looking opinions.

    Read the article

  • Matlab Simulink version control with multiple developers

    - by Jon Mills
    We're using Matlab Simulink for model development (and Real-Time Workshop autocoding) within a team of several developers. We currently use Visual Source Safe (yes, I know its terrible) for version control, using locks to prevent conflicting changes. We'd like to migrate our programme to a different version control system (svn, hg or git), but we're concerned about performing merges and diffs on Simulink .mdl files. Does anybody have useful experience in performing merges on Simulink files?

    Read the article

  • JAX-WS client with Axis service

    - by Jon
    I'm relatively new to web services, but I need to integrate a call to an existing service in my application. Ideally, I'd like to use JAX-WS because I'm looking for the simplest, quickest-to-develop solution on my end, and MyEclipse is able to generate a JAX-WS client from a WSDL. Unfortunately, the WSDL I've inherited was built from what appears to be Axis using RPC. Will this still work? When trying to generate the code, I get these errors, and the web searches I've found seem to say that it's the service end that needs to upgrade: <restriction base="soapenc:Array"> <attribute ref="soapenc:arrayType" wsdl:arrayType="impl:MyTypeList[]" /> </restriction> WS-I: (BP2108) An Array declaration uses - restricts or extends - the soapEnc:Array type, or the wsdl:arrayType attribute is used in the type declaration WS-I: (BP2122) A wsdl:types element contained a data type definition that is not an XML schema definition <wsdlsoap:body encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" namespace="http://ws.host.com" use="encoded" / WS-I: (BP2406) The use attribute of a soapbind:body, soapbind:fault, soapbind:header and soapbind:headerfault does not have value of "literal".

    Read the article

  • How to structure VB.NET windows forms applications

    - by Jon
    What is the best way to structure a VB.NET windows forms application so that code can be reused and the app can be extended easily. I used to create lots of new forms. This lead to lots of repeated code and forms which did similar things. Now, for forms which do similar jobs, such as view/edit/delete items from a specific db table, I create a form with the required controls, have the form create an instance of a class with params such as a collection of the controls and a string containing the db table name. Then the individual controls call functions of the class. Advanced forms will inherit and extend this basic form class. 1) Has there already been work done in this area? 2) Are there books / articles available which discuss the options available on this topic? Thanks!

    Read the article

  • Installing Fabric On Windows (Error No Module Called Readline)

    - by Jon
    I'm trying to use the Fabric 0.1.1 deploy tool (http://docs.fabfile.org/) on Windows and we're running into an issue with the readline module. I've been through various threads but can't seem to solve the issue. It's important because we can't deploy applications from Windows based machines. C:\Documents and Settings\dev\Desktop\deploy>fab Traceback (most recent call last): File "C:\python\Scripts\fab-script.py", line 8, in <module> load_entry_point('fabric==0.1.1', 'console_scripts', 'fab')() File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\pkg_resources.py" , line 277, in load_entry_point File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\pkg_resources.py" , line 2180, in load_entry_point File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\pkg_resources.py" , line 1913, in load File "build\bdist.win32\egg\fabric.py", line 25, in <module> **ImportError: No module named readline** Installing the module results in: **easy_install readline** Searching for readline Reading http://pypi.python.org/simple/readline/ Reading http://www.python.org/ Best match: readline 2.6.4 Downloading http://pypi.python.org/packages/source/r/readline/readline-2.6.4.tar .gz#md5=7568e8b78f383443ba57c9afec6f4285 Processing readline-2.6.4.tar.gz Running readline-2.6.4\setup.py -q bdist_egg --dist-dir c:\docume~1\ji81b9~1.che \locals~1\temp\easy_install-pzkz1a\readline-2.6.4\egg-dist-tmp-szs2ps Traceback (most recent call last): File "C:\python\Scripts\easy_install-script.py", line 8, in <module> load_entry_point('setuptools==0.6c9', 'console_scripts', 'easy_install')() File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 1671, in main File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 1659, in with_ei_usage File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 1675, in <lambda> File "c:\python\lib\distutils\core.py", line 152, in setup dist.run_commands() File "c:\python\lib\distutils\dist.py", line 975, in run_commands self.run_command(cmd) File "c:\python\lib\distutils\dist.py", line 995, in run_command cmd_obj.run() File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 211, in run File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 446, in easy_install File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 476, in install_item File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 655, in install_eggs File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 930, in build_and_install File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\comman d\easy_install.py", line 919, in run_setup File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\sandbo x.py", line 27, in run_setup File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\sandbo x.py", line 63, in run File "c:\python\lib\site-packages\setuptools-0.6c9-py2.6.egg\setuptools\sandbo x.py", line 29, in <lambda> File "setup.py", line 93, in <module> AttributeError: 'module' object has no attribute 'symlink' Has anybody solved this issue or can anybody suggest a workaround?

    Read the article

  • Upgrade to Azure 2.2 SDK is causing roles to fail

    - by Jon Leach
    I have 3 worker roles and a web role in my project and I upgraded it to the new 2.2 SDK (required in VS2013). Ever since the upgrade, all of the worker roles are failing and they instantly recycle as soon as they're started. When the roles start, I'm getting these messages: Microsoft.WindowsAzure.ServiceRuntime Information: 200 : Role entrypoint . CALLING OnStart() Microsoft.WindowsAzure.ServiceRuntime Information: 202 : Role entrypoint . COMPLETED OnStart() The thread 0x441c has exited with code 259 (0x103). Microsoft.WindowsAzure.ServiceRuntime Information: 203 : Role entrypoint . CALLING Run() Microsoft.WindowsAzure.ServiceRuntime Warning: 204 : Role entrypoint . COMPLETED Run() ==> ROLE RECYCLING INITIATED Microsoft.WindowsAzure.ServiceRuntime Information: 503 : Role instance recycling is starting The thread 0x2684 has exited with code 259 (0x103) Two things draw my attention: I've started to see a bunch of errors "Cannot find or open the PDB file." But I don't know that this is directly relevant. I'm using VS 2013 and while the project lists the SDK as 2.2, the references within the roles are the 2.1 versions. Do I need to upgrade the components? Why wouldn't the project upgrade these automatically when I pulled the project into VS as it only support 2.2? Any thoughts on how to attach this are appreciated.

    Read the article

  • WPF MenuItem ViewModel Command

    - by Jon Archway
    Hi, I am fairly new to WPF and am struggling a little with a scenario. I have a menu which has menu items. When one of these menu items gets clicked a method needs to be called that will do something based upon the text displayed associated with that menu item. So for example, the menu item's content was "test" so I would need to do something with "test". FYI, this "something" directly affects a collection on the ViewModel. This is easy to achieve using the click event and no ViewModel, but I was trying to implement MVVM using an explicit ViewModel. So I started to look into Commands but cannot see how I would pass anything from the View back into the Command in the ViewModel. Any suggestions on what I should be doing here? Thanks

    Read the article

  • What's the best name for a non-mutating "add" method on an immutable collection?

    - by Jon Skeet
    Sorry for the waffly title - if I could come up with a concise title, I wouldn't have to ask the question. Suppose I have an immutable list type. It has an operation Foo(x) which returns a new immutable list with the specified argument as an extra element at the end. So to build up a list of strings with values "Hello", "immutable", "world" you could write: var empty = new ImmutableList<string>(); var list1 = empty.Foo("Hello"); var list2 = list1.Foo("immutable"); var list3 = list2.Foo("word"); (This is C# code, and I'm most interested in a C# suggestion if you feel the language is important. It's not fundamentally a language question, but the idioms of the language may be important.) The important thing is that the existing lists are not altered by Foo - so empty.Count would still return 0. Another (more idiomatic) way of getting to the end result would be: var list = new ImmutableList<string>().Foo("Hello"); .Foo("immutable"); .Foo("word"); My question is: what's the best name for Foo? EDIT 3: As I reveal later on, the name of the type might not actually be ImmutableList<T>, which makes the position clear. Imagine instead that it's TestSuite and that it's immutable because the whole of the framework it's a part of is immutable... (End of edit 3) Options I've come up with so far: Add: common in .NET, but implies mutation of the original list Cons: I believe this is the normal name in functional languages, but meaningless to those without experience in such languages Plus: my favourite so far, it doesn't imply mutation to me. Apparently this is also used in Haskell but with slightly different expectations (a Haskell programmer might expect it to add two lists together rather than adding a single value to the other list). With: consistent with some other immutable conventions, but doesn't have quite the same "additionness" to it IMO. And: not very descriptive. Operator overload for + : I really don't like this much; I generally think operators should only be applied to lower level types. I'm willing to be persuaded though! The criteria I'm using for choosing are: Gives the correct impression of the result of the method call (i.e. that it's the original list with an extra element) Makes it as clear as possible that it doesn't mutate the existing list Sounds reasonable when chained together as in the second example above Please ask for more details if I'm not making myself clear enough... EDIT 1: Here's my reasoning for preferring Plus to Add. Consider these two lines of code: list.Add(foo); list.Plus(foo); In my view (and this is a personal thing) the latter is clearly buggy - it's like writing "x + 5;" as a statement on its own. The first line looks like it's okay, until you remember that it's immutable. In fact, the way that the plus operator on its own doesn't mutate its operands is another reason why Plus is my favourite. Without the slight ickiness of operator overloading, it still gives the same connotations, which include (for me) not mutating the operands (or method target in this case). EDIT 2: Reasons for not liking Add. Various answers are effectively: "Go with Add. That's what DateTime does, and String has Replace methods etc which don't make the immutability obvious." I agree - there's precedence here. However, I've seen plenty of people call DateTime.Add or String.Replace and expect mutation. There are loads of newsgroup questions (and probably SO ones if I dig around) which are answered by "You're ignoring the return value of String.Replace; strings are immutable, a new string gets returned." Now, I should reveal a subtlety to the question - the type might not actually be an immutable list, but a different immutable type. In particular, I'm working on a benchmarking framework where you add tests to a suite, and that creates a new suite. It might be obvious that: var list = new ImmutableList<string>(); list.Add("foo"); isn't going to accomplish anything, but it becomes a lot murkier when you change it to: var suite = new TestSuite<string, int>(); suite.Add(x => x.Length); That looks like it should be okay. Whereas this, to me, makes the mistake clearer: var suite = new TestSuite<string, int>(); suite.Plus(x => x.Length); That's just begging to be: var suite = new TestSuite<string, int>().Plus(x => x.Length); Ideally, I would like my users not to have to be told that the test suite is immutable. I want them to fall into the pit of success. This may not be possible, but I'd like to try. I apologise for over-simplifying the original question by talking only about an immutable list type. Not all collections are quite as self-descriptive as ImmutableList<T> :)

    Read the article

  • Learning WPF GUI design

    - by Jon
    GUI's written using WPF seem to be closer to a Web 2.0 feel than older Winforms development has been; do you know of any good quality references online or books which give a general overview of how to design nice WPF applications? I saw this StackOverflow question where some GUI design books are mentioned, but am interested in information specifically for WPF. http://stackoverflow.com/questions/1193001/is-wpf-silverlight-design-worth-learning Thanks!

    Read the article

  • PDF Text Extraction Approach Using OCR

    - by Jon
    Has anybody attempted to extract text from a PDF using an OCR library and Java? What did you find to be the most reliable library for text extraction. Most of the approaches I've seen (tesseract, GOCR) are C libraries that would require some JNI code to be written. I'm familiar with pdfbox, which is now an Apache incubator project at version 0.8.x, but it's text extraction isn't always accurate. I'm looking for an alternative approach that is somewhat more reliable. I've not tried Asprise JavaPDF yet, in the process of trying that, but wanted to know more about the OCR approach (if it's possible). Any help would be appreciated.

    Read the article

  • C# file Decryption - Bad Data

    - by Jon
    Hi all, I am in the process of rewriting an old application. The old app stored data in a scoreboard file that was encrypted with the following code: private const String SSecretKey = @"?B?n?Mj?"; public DataTable GetScoreboardFromFile() { FileInfo f = new FileInfo(scoreBoardLocation); if (!f.Exists) { return setupNewScoreBoard(); } DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); //A 64 bit key and IV is required for this provider. //Set secret key For DES algorithm. DES.Key = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Set initialization vector. DES.IV = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Create a file stream to read the encrypted file back. FileStream fsread = new FileStream(scoreBoardLocation, FileMode.Open, FileAccess.Read); //Create a DES decryptor from the DES instance. ICryptoTransform desdecrypt = DES.CreateDecryptor(); //Create crypto stream set to read and do a //DES decryption transform on incoming bytes. CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read); DataTable dTable = new DataTable("scoreboard"); dTable.ReadXml(new StreamReader(cryptostreamDecr)); cryptostreamDecr.Close(); fsread.Close(); return dTable; } This works fine. I have copied the code into my new app so that I can create a legacy loader and convert the data into the new format. The problem is I get a "Bad Data" error: System.Security.Cryptography.CryptographicException was unhandled Message="Bad Data.\r\n" Source="mscorlib" The error fires at this line: dTable.ReadXml(new StreamReader(cryptostreamDecr)); The encrypted file was created today on the same machine with the old code. I guess that maybe the encryption / decryption process uses the application name / file or something and therefore means I can not open it. Does anyone have an idea as to: A) Be able explain why this isn't working? B) Offer a solution that would allow me to be able to open files that were created with the legacy application and be able to convert them please? Thank you

    Read the article

  • Expected output from an RM-1501 RS232 interface?

    - by Jon Cage
    I have an old RM-1501 digital tachometer which I'm using to try to identify the speed of an object. According to the manual I should be able to read the data over a serial link. Unfortunately, I don't appear to be able to get any sensible output from the device (never gives a valid speed). I think it might be a signalling problem because disconnecting the CTS line starts to get some data through.. Has anyone ever developed anything for one of these / had any success?

    Read the article

  • How can I make the SmartGWT core smaller?

    - by Jon Anter
    I have recently written a Hello World application using SmartGWT and noticed that the size of the application is huge. In my case it is over 600kb just for that application. I think that size is obscene so I narrowed the culprit down to two core libraries, ISC_Core and ISC_Foundation which combine for a total size of 649kb. Is there anyway to reduce the bloat of these libraries? Any help would be appreciated.

    Read the article

  • SSAS/SSRS remove parameter from cube report destroys report

    - by Jon
    Group, We built a data cube using SSAS and are now building SSRS reports off of that cube. Not sure if anyone has come across this, but when you build the report using the wizard and include parameters all looks fine. However if you are in the report after the wizard is compete, and you decide you want to remove one of the parameters you created it debunks the report and the only way to get it back is to re-create the whole report. Any way you can remove or add parameters after the initial build without destroying your report? Thanks in advance for the help! I love this forumn!

    Read the article

  • Implementing an async "read all currently available data from stream" operation

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a console's standard output Stream. Console output streams are of type FileStream; the implementation can cast to that, if needed. There is also an associated StreamReader already present to leverage. There is only one thing I need to implement in this class to achieve my desired functionality: an async "read all the data available this moment" operation. Reading to the end of the stream is not viable because the stream will not end unless the process closes the console output handle, and it will not do that because it is interactive and expecting input before continuing. I will be using that hypothetical async operation to implement event-based notification, which will be more convenient for my callers. The public interface of the class is this: public class ConsoleAutomator { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Remember that the goal here is to read all of the chunk and call event subscribers exactly once for each chunk. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream. private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer (in which case we know that there was no more data to be read during the last read operation), all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Never more than one event for each time data is available to be read Is almost agnostic to the buffer size The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this. Update: I definitely did not communicate the scenario well in my initial writeup. I have since revised the writeup quite a bit, but to be extra sure: The question is about how to implement an async "read all the data available this moment" operation. My apologies to the people who took the time to read and answer without me making my intent clear enough.

    Read the article

< Previous Page | 52 53 54 55 56 57 58 59 60 61 62 63  | Next Page >