Search Results

Search found 5648 results on 226 pages for 'collection'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 96/226 | < Previous Page | 92 93 94 95 96 97 98 99 100 101 102 103  | Next Page >

  • Is there a system monitoring tool that lets me write complex queries against the data?

    - by benhsu
    I am looking for a system stat collection tool that will let me write queries against the data collected. I am planning to answer questions like: what is the average load, over the last 30 days, on this machine between 9AM and 5PM, as opposed to at night what was the average disk io on these 10 machines yesterday what was the average daytime memory usage on these 10 machines last week, as opposed to 2 weeks ago Has anyone done this with, say, collectd or graphite?

    Read the article

  • how to change zone of a extented webapplication-SharePoint?

    - by Ryan
    I have extended a webapplication and set its zone to Intranet but now we decided to make that site anonymous I made all the settings in authentication provider and site collection settings but its still showing its zone as Intranet . I read that its best practice to keep Internet as the zone for anonymous access.. How can I change it now and does it affect leaving it as Intranet?

    Read the article

  • How to tune system settings for mongoDB on Linux?

    - by jsh
    Trying to squeeze a lot out of one question here -- please bear with me. Although the MongoDB man pages make several useful recommendations about system settings like ulimit (http://docs.mongodb.org/manual/reference/ulimit/), and other production factors (http://docs.mongodb.org/manual/administration/production-notes/) they seem mysteriously silent on things like virtual memory and swap settings. The closest we get to a hint is that "...the operating system’s virtual memory subsystem manages MongoDB’s memory..." (http://docs.mongodb.org/manual/faq/fundamentals/#does-mongodb-require-a-lot-of-ram). Running the same job - high writes and high reads on about 10,000,000 records in a single collection -- on my 4-processor, 4GB RAM macbook and an 8-core ubuntu box with 64GB RAM I saw dramatically WORSE read performance on the linux box with factory settings, and could hear the disk constantly spinning, indicating high I/O and presumably swapping. Yes, other things were happening on the box, but there was plenty of free RAM, disk space, etc.; furthermore, I did not see evidence that Mongo was expanding to take advantage of all that free RAM as it is touted to do. Linux box default settings were as follows: vm.swappiness =60 vm.dirty_background_ratio = 10 vm.dirty_ratio = 20 vm.dirty_expire_centisecs =3000 vm.dirty_writeback_centisecs=500 I hazarded some guesses looking at docs and blogs for other types of databases (Oracle, MYSQL, etc.), experimented, and adjusted as below. vm.swappiness=10 vm.dirty_background_ratio=5 vm.dirty_ratio=5 vm.dirty_writeback_centisecs=250 vm.dirty_expire_centisecs=500 I saw some immediate apparent improvements in read time. However, when I ran my test jobs again, read performance continued to be painfully sluggish during heavy writes. Then, I REBUILT the collection from an available data source - and suddenly I can read at 1ms or less per record WHILE doing the write job! So the question is really two-fold: 1) What are appropriate VM settings for MongoDB on Linux? 2) (bonus) Does Mongo do some checking or optimization with the OS while data is being built? In other words, if I have built a large data set with suboptimal VM or I/O settings, does Mongo make assumptions during the memory-mapping process that will fail to take advantage of optimizations down the road? Obviously I don't fully grok memory mapping under the hood (I was hoping I wouldn't have to). Any help appreciated...thanks! -j

    Read the article

  • VLC Dynamic Range compression multiple songs

    - by Sion
    In my collection of music I have some songs which seem to be compressed nicely. But in addition to those I have songs which are overly quite compared to the louder compressed songs. So maybe the problem isn't compression but average volume. Would the Dynamic Range Compressor in VLC work for this type of problem or would I have better luck using external speakers and running it through a guitar compressor?

    Read the article

  • Moving media files while preserving itunes rating

    - by akurtser
    Hi, I've seen many threads on how to move an entire media collection from one machine to another. I want to organize my mp3 directories, but any copied file loses its reference from itunes library, thus, when I add it to itunes again, it'll have no rating data. I guess it's possible if I manipulate the itunes xml database, but I really don't want to mess with it "by hand".

    Read the article

  • Limit display/session resolution for machines @ VDI environment on RDS 2012

    - by WarP
    I have couple of windows 7 entprise virtual machines in collection as part of VDI environment - so users connecting to them through RDS 2012 web site. Is there any way to fix resolution of remote desktops, that user receives (instead of full screen all time) ? I've tried different group policies, but none of them are worked, probably because all those policies are for RDS sessions and not virtual desktops ... And i don't know how to limit resolution locally on win7 machine itself, so connecting users will receive fixed resolution.

    Read the article

  • How to give Apache access to files in my home directory?

    - by Mark Smith
    I'm a Ubuntu Linux user (Lucid Lynx) who is running Apache. I have a collection of zip files in a folder in my home directory (~/zip_files) which I would like to be able to link to through apache, such that when somebody who visits my website which I'm using Apache to host clicks a link to one of the zip files, he can download it through the web. How can I provide Apache with access to the files and set the permissions? Thanks, I'm new to linux!

    Read the article

  • Is there software to automatically change song speed without transposing it

    - by Peter P
    Goal: automatically adjusting speed (bpm) of a given set of MP3 files in order to have a collection of music optimized to be heard when I am running. (I realized that I prefer to run with about 168 bpm in my ears). Of course, I could have some software to detect BPM and then calculate and stretch/squeeze each song using Audacity or a similar tool, however, I'd prefer a solution which requires less manual operation.

    Read the article

  • What is the bitrate of itunes streaming

    - by The Journeyman geek
    I've been using itunes streaming (in part cause its easy) to access my music collection between two windows PCs. I'm half certain it sounds kinda 'flat' so i'm wondering, what bitrate it uses, and format - it sounds fine off a PMP, and even better on a PC, so i assume i can tell the difference.

    Read the article

  • Retry failed downloads - Google Music Manager

    - by Severin
    After my old computer died I wanted to download my music collection from Google Music - which is very easy with Googles Music Manager. After a few hours it had downloaded my library, but also showed around 300 download errors. Downloading the library another time, however, made different files fail (Which tells me that the error isn't connected to the files as such). Does anybody know of a way how to retry only the songs that failed downloading?

    Read the article

  • Moving a window that can't be dragged by the title bar?

    - by ccat
    I have Fallout Collection and I am trying to run it windowed because of the low resolution. When I change the mode to windowed via the .ini file, however, it starts the game with the window shoved into the upper left corner of my screen. Clicking the title bar of the window just clicks back into the game program. So how can I move it to the center of my screen? I am using Windows 7 professional 64-bit.

    Read the article

  • What logs should I collect from a Windows server network?

    - by Cygnus X
    I'm setting up a log collection server for my Windows network (about 30 servers ranging from 2003 to 2008 R2, and about 300 vista/7 clients), and I was wondering which logs are good to collect and which ones are a waste of time. I'm going to collect the obvious ones (system, security, event, firewall, and role specific logs) but are there any others I should be worried about? I'm using Splunk if that helps answer the question.

    Read the article

  • Moving a game in windowed mode that can't be dragged by the title bar.

    - by ccat
    I have Fallout Collection and I am trying to run it windowed because of the low resolution. When I change the mode to windowed via the .ini file, however, it boots the game window shoved into the upper left corner of my screen. I can't click the title bar of the window because it just clicks back into the game program. So how can I move it to the center of my screen? I am using Windows 7 professional 64-bit.

    Read the article

  • rsync directories

    - by Buzzzz
    Hello, I'm trying to sync my music collection between my mac and my linux workstation but fails to mirror from my server share to linux. rsync -avz --progress Music/ /volumes/myserver/music works fine but the reverse on my linux ws doesnt. rsync -avz --progress /path/to/samba/share/music/ ~/Music does nothing.. Any clue what I have gotten wrong with this?? Best Regards Anders Olme

    Read the article

  • ViewPager cycle between views?

    - by Erdem Azakli
    I want my ViewPager implementation to cycle between views instead of stopping at the last view. For example, if I have 3 views to display via a ViewPager, it should return back to the first View after the third View on fling instead of stopping at that third view. I want it to return to the first page/view when the user flings forward on the last page Thanks, Mypageradapter; package com.example.pictures; import android.content.Context; import android.media.AudioManager; import android.os.Parcelable; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.view.LayoutInflater; import android.view.View; public class MyPagerAdapter extends PagerAdapter{ SoundManager snd; int sound1,sound2,sound3; boolean loaded = false; public int getCount() { return 6; } public Object instantiateItem(View collection, int position) { View view=null; LayoutInflater inflater = (LayoutInflater) collection.getContext() .getSystemService(Context.LAYOUT_INFLATER_SERVICE); this.setVolumeControlStream(AudioManager.STREAM_MUSIC); int resId = 0; switch (position) { case 0: resId = R.layout.picture1; view = inflater.inflate(resId, null); break; case 1: resId = R.layout.picture2; view = inflater.inflate(resId, null); break; case 2: resId = R.layout.picture3; view = inflater.inflate(resId, null); break; case 3: resId = R.layout.picture4; view = inflater.inflate(resId, null); break; case 4: resId = R.layout.picture5; view = inflater.inflate(resId, null); break; case 5: resId = R.layout.picture6; view = inflater.inflate(resId, null); break; } ((ViewPager) collection).addView(view, 0); return view; } @SuppressWarnings("unused") private Context getApplicationContext() { // TODO Auto-generated method stub return null; } private void setVolumeControlStream(int streamMusic) { // TODO Auto-generated method stub } @SuppressWarnings("unused") private Context getBaseContext() { // TODO Auto-generated method stub return null; } @SuppressWarnings("unused") private PagerAdapter findViewById(int myfivepanelpager) { // TODO Auto-generated method stub return null; } @Override public void destroyItem(View arg0, int arg1, Object arg2) { ((ViewPager) arg0).removeView((View) arg2); } @Override public boolean isViewFromObject(View arg0, Object arg1) { return arg0 == ((View) arg1); } @Override public Parcelable saveState() { return null; } public static Integer getItem(int position) { // TODO Auto-generated method stub return null; } } OnPageChangeListener; package com.example.pictures; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.view.View; import android.widget.Button; import android.widget.Toast; public class Pictures extends Activity implements OnPageChangeListener{ SoundManager snd; int sound1,sound2,sound3; View view=null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.picturespage); MyPagerAdapter adapter = new MyPagerAdapter(); ViewPager myPager = (ViewPager) findViewById(R.id.myfivepanelpager); myPager.setAdapter(adapter); myPager.setCurrentItem(0); myPager.setOnPageChangeListener(this); snd = new SoundManager(this); sound1 = snd.load(R.raw.sound1); sound2 = snd.load(R.raw.sound2); sound3 = snd.load(R.raw.sound3); } public void onPageScrollStateChanged(int arg0) { // TODO Auto-generated method stub } public void onPageScrolled(int arg0, float arg1, int arg2) { // TODO Auto-generated method stub } public void onPageSelected(int position) { // TODO Auto-generated method stub switch (position) { case 0: snd.play(sound1); break; case 1: snd.play(sound2); break; case 2: snd.play(sound3); break; case 3: Toast.makeText(this, "1", Toast.LENGTH_SHORT).show(); break; case 4: Toast.makeText(this, "2", Toast.LENGTH_SHORT).show(); break; case 5: Toast.makeText(this, "3", Toast.LENGTH_SHORT).show(); break; } } };

    Read the article

  • CheckBox ListView SelectedValues DependencyProperty Binding

    - by Ristogod
    I am writing a custom control that is a ListView that has a CheckBox on each item in the ListView to indicate that item is Selected. I was able to do so with the following XAML. <ListView x:Class="CheckedListViewSample.CheckBoxListView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d"> <ListView.Style> <Style TargetType="{x:Type ListView}"> <Setter Property="SelectionMode" Value="Multiple" /> <Style.Resources> <Style TargetType="ListViewItem"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ListViewItem"> <Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="{TemplateBinding Control.Padding}" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" SnapsToDevicePixels="True"> <CheckBox IsChecked="{Binding IsSelected, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListViewItem}}}"> <CheckBox.Content> <ContentPresenter Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" /> </CheckBox.Content> </CheckBox> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> </Style.Resources> </Style> </ListView.Style> </ListView> I however am trying to attempt one more feature. The ListView has a SelectedItems DependencyProperty that returns a collection of the Items that are checked. However, I need to implement a SelectedValues DependencyProperty. I also am implementing a SelectedValuesPath DependencyProperty. By using the SelectedValuesPath, I indicate the path where the values are found for each selected item. So if my items have an ID property, I can specify using the SelectedValuesPath property "ID". The SelectedValues property would then return a collection of ID values. I have this working also using this code in the code-behind: using System.Windows; using System.Windows.Controls; using System.ComponentModel; using System.Collections; using System.Collections.Generic; namespace CheckedListViewSample { /// <summary> /// Interaction logic for CheckBoxListView.xaml /// </summary> public partial class CheckBoxListView : ListView { public static DependencyProperty SelectedValuesPathProperty = DependencyProperty.Register("SelectedValuesPath", typeof(string), typeof(CheckBoxListView), new PropertyMetadata(string.Empty, null)); public static DependencyProperty SelectedValuesProperty = DependencyProperty.Register("SelectedValues", typeof(IList), typeof(CheckBoxListView), new PropertyMetadata(new List<object>(), null)); [Category("Appearance")] [Localizability(LocalizationCategory.NeverLocalize)] [Bindable(true)] public string SelectedValuesPath { get { return ((string)(base.GetValue(CheckBoxListView.SelectedValuesPathProperty))); } set { base.SetValue(CheckBoxListView.SelectedValuesPathProperty, value); } } [Bindable(true)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] [Category("Appearance")] public IList SelectedValues { get { return ((IList)(base.GetValue(CheckBoxListView.SelectedValuesPathProperty))); } set { base.SetValue(CheckBoxListView.SelectedValuesPathProperty, value); } } public CheckBoxListView() : base() { InitializeComponent(); base.SelectionChanged += new SelectionChangedEventHandler(CheckBoxListView_SelectionChanged); } private void CheckBoxListView_SelectionChanged(object sender, SelectionChangedEventArgs e) { List<object> values = new List<object>(); foreach (var item in SelectedItems) { if (string.IsNullOrWhiteSpace(SelectedValuesPath)) { values.Add(item); } else { try { values.Add(item.GetType().GetProperty(SelectedValuesPath).GetValue(item, null)); } catch { } } } base.SetValue(CheckBoxListView.SelectedValuesProperty, values); e.Handled = true; } } } My problem is that my binding only works one way right now. I'm having trouble trying to figure out how to implement my SelectedValues DependencyProperty so that I could Bind a Collection of values to it, and when the control is loaded, the CheckBoxes are checked with items that have values that correspond to the SelectedValues. I've considered using the PropertyChangedCallBack event, but can't quite figure out how I could write that to achieve my goal. I'm also unsure of how I find the correct ListViewItem to set it as Selected. And lastly, if I can find the ListViewItem and set it to be Selected, won't that fire my SelectionChanged event each time I set a ListViewItem to be Selected?

    Read the article

  • Themes wont work when using Server Side Tags on an ASP.NET Page

    - by Sumit Sharma
    The code for the asp.net page is: <div class="facebox_content"> <% if (CurrentUser.Role == "Free") { %> <table cellpadding="0" cellspacing="0" style="border-collapse:collapse;width:380px;"> <tr> <td> User Name : </td> <td> Membership Cost : </td> </tr> <tr> <td style="width:190px;"> <asp:TextBox ID="txtUserName" Enabled="false" runat="server" Text="<%= CurrentUser.Name %>"/> </td> <td style="width:190px;"> <asp:TextBox ID="txtCost" Enabled="false" runat="server" Text="2000"/> </td> </tr> <tr> <td> <br /> Cheque / Draft No.: </td> <td> <br /> Bank Drawn On : </td> </tr> <tr> <td style="width:190px;"> <asp:TextBox ID="txtChqNo" runat="server"></asp:TextBox> </td> <td style="width:190px;"> <asp:TextBox ID="txtBankName" runat="server"></asp:TextBox> </td> </tr> <tr> <td> <br /> Date : </td> <td> <br /> City : </td> </tr> <tr> <td style="width:190px;"> <asp:TextBox ID="txtDate" runat="server"></asp:TextBox> </td> <td style="width:190px;"> <asp:TextBox ID="txtCity" runat="server"></asp:TextBox> </td> </tr> </table> <% } else if(CurrentUser.Role == "Pending") { %> <p style="text-align:justify;"> Your Request is pending with our Administrators. Please be patient while your request is processed. Usually it takes 2-4 Days for your request to be processed after the payment has been received. </p> <% } else if(CurrentUser.Role == "Paid") { %> <p style="text-align:justify;"> You are already a Paid Member of Website </p> <% } %> The code for the C# file is: protected void Page_PreInit(object sender, EventArgs e) { this.Theme = CurrentUser.Theme; } protected void Page_Load(object sender, EventArgs e) { txtUserName.Text = CurrentUser.Name; ConfirmButton.Attributes.Add("onclick", "javascript:document.getElementById('" + lblMsg.ClientID + "').style.display='none';"); if (CurrentUser.Role != "Free") ConfirmButton.Visible = false; } The code is giving the following error: The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>). Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Web.HttpException: The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>). Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [HttpException (0x80004005): The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).] System.Web.UI.ControlCollection.Add(Control child) +8678903 System.Web.UI.PageTheme.SetStyleSheet() +478 System.Web.UI.Page.OnInit(EventArgs e) +8699660 System.Web.UI.Control.InitRecursive(Control namingContainer) +333 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +378 Please some one help me out..!!

    Read the article

  • How to add OnClickListener in ViewPager

    - by Erdem Azakli
    I have problem with ViewPager and can't find answer.I want to Toast a message when pictures(view) clicked. I can't make, please help me. Example: click on the picture1 --Message"Picture1" click on the picture2 --Message"Picture2" Thanks a lot, Mypageradapter; package com.example.pictures; import android.content.Context; import android.media.AudioManager; import android.os.Parcelable; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.view.LayoutInflater; import android.view.View; public class MyPagerAdapter extends PagerAdapter{ public int getCount() { return 6; } public Object instantiateItem(View collection, int position) { View view=null; LayoutInflater inflater = (LayoutInflater) collection.getContext() .getSystemService(Context.LAYOUT_INFLATER_SERVICE); int resId = 0; switch (position) { case 0: resId = R.layout.picture1; view = inflater.inflate(resId, null); break; case 1: resId = R.layout.picture2; view = inflater.inflate(resId, null); break; case 2: resId = R.layout.picture3; view = inflater.inflate(resId, null); break; case 3: resId = R.layout.picture4; view = inflater.inflate(resId, null); break; case 4: resId = R.layout.picture5; view = inflater.inflate(resId, null); break; case 5: resId = R.layout.picture6; view = inflater.inflate(resId, null); break; } ((ViewPager) collection).addView(view, 0); return view; } @SuppressWarnings("unused") private Context getApplicationContext() { // TODO Auto-generated method stub return null; } private void setVolumeControlStream(int streamMusic) { // TODO Auto-generated method stub } @SuppressWarnings("unused") private Context getBaseContext() { // TODO Auto-generated method stub return null; } @SuppressWarnings("unused") private PagerAdapter findViewById(int myfivepanelpager) { // TODO Auto-generated method stub return null; } @Override public void destroyItem(View arg0, int arg1, Object arg2) { ((ViewPager) arg0).removeView((View) arg2); } @Override public boolean isViewFromObject(View arg0, Object arg1) { return arg0 == ((View) arg1); } @Override public Parcelable saveState() { return null; } public static Integer getItem(int position) { // TODO Auto-generated method stub return null; } } OnPageChangeListener; package com.example.pictures; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.view.View; import android.widget.Button; import android.widget.Toast; public class Pictures extends Activity implements OnPageChangeListener{ SoundManager snd; int sound1,sound2,sound3; View view=null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.picturespage); MyPagerAdapter adapter = new MyPagerAdapter(); ViewPager myPager = (ViewPager) findViewById(R.id.myfivepanelpager); myPager.setAdapter(adapter); myPager.setCurrentItem(0); myPager.setOnPageChangeListener(this); snd = new SoundManager(this); sound1 = snd.load(R.raw.sound1); sound2 = snd.load(R.raw.sound2); sound3 = snd.load(R.raw.sound3); } public void onPageScrollStateChanged(int arg0) { // TODO Auto-generated method stub } public void onPageScrolled(int arg0, float arg1, int arg2) { // TODO Auto-generated method stub } public void onPageSelected(int position) { // TODO Auto-generated method stub switch (position) { case 0: snd.play(sound1); break; case 1: snd.play(sound2); break; case 2: snd.play(sound3); break; case 3: Toast.makeText(this, "1", Toast.LENGTH_SHORT).show(); break; case 4: Toast.makeText(this, "2", Toast.LENGTH_SHORT).show(); break; case 5: Toast.makeText(this, "3", Toast.LENGTH_SHORT).show(); break; } } };

    Read the article

  • Is multithreading the right way to go for my case?

    - by Julien Lebosquain
    Hello, I'm currently designing a multi-client / server application. I'm using plain good old sockets because WCF or similar technology is not what I need. Let me explain: it isn't the classical case of a client simply calling a service; all clients can 'interact' with each other by sending a packet to the server, which will then do some action, and possible re-dispatch an answer message to one or more clients. Although doable with WCF, the application will get pretty complex with hundreds of different messages. For each connected client, I'm of course using asynchronous methods to send and receive bytes. I've got the messages fully working, everything's fine. Except that for each line of code I'm writing, my head just burns because of multithreading issues. Since there could be around 200 clients connected at the same time, I chose to go the fully multithreaded way: each received message on a socket is immediately processed on the thread pool thread it was received, not on a single consumer thread. Since each client can interact with other clients, and indirectly with shared objects on the server, I must protect almost every object that is mutable. I first went with a ReaderWriterLockSlim for each resource that must be protected, but quickly noticed that there are more writes overall than reads in the server application, and switched to the well-known Monitor to simplify the code. So far, so good. Each resource is protected, I have helper classes that I must use to get a lock and its protected resource, so I can't use an object without getting a lock. Moreover, each client has its own lock that is entered as soon as a packet is received from its socket. It's done to prevent other clients from making changes to the state of this client while it has some messages being processed, which is something that will happen frequently. Now, I don't just need to protect resources from concurrent accesses. I must keep every client in sync with the server for some collections I have. One tricky part that I'm currently struggling with is the following: I have a collection of clients. Each client has its own unique ID. When a client connects, it must receive the IDs of every connected client, and each one of them must be notified of the newcomer's ID. When a client disconnects, every other client must know it so that its ID is no longer valid for them. Every client must always have, at a given time, the same clients collection as the server so that I can assume that everybody knows everybody. This way if I'm sending a message to client #1 telling "Client #2 has done something", I know that it will always be correctly interpreted: Client 1 will never wonder "but who is Client 2 anyway?". My first attempt for handling the connection of a new client (let's call it X) was this pseudo-code (remember that newClient is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("newClient with id X has connected"); } } clients.Add(newClient); newClient.Send("the list of other clients"); } Now imagine that in the same time, another client has sent a packet that translates into a message that must be broadcasted to every connected client, the pseudo-code will be something like this (remember that the current client - let's call it Y - is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("something"); } } } An obvious deadlock occurs here: on one thread X is locked, the clients lock has been entered, started looping through the clients, and at one moment must get Y's lock... which is already acquired on the second thread, itself waiting for the clients collection lock to be released! This is not the only case like this in the server application. There are other collections which must be kept in sync with the clients, some properties on a client can be changed by another one, etc. I tried other types of locks, lock-free mechanisms and a bunch of other things. Either there were obvious deadlocks when I'm using too much locks for safety, or obvious race conditions otherwise. When I finally find a good middle point between the two, it usually comes with very subtle race conditions / dead locks and other multi-threading issues... my head hurts very quickly since for any single line of code I'm writing I have to review almost the whole application to ensure everything will behave correctly with any number of threads. So here's my final question: how would you resolve this specific case, the general case, and more importantly: aren't I going the wrong way here? I have little problems with the .NET framework, C#, simple concurrency or algorithms in general. Still, I'm lost here. I know I could use only one thread processing the incoming requests and everything will be fine. However, that won't scale well at all with more clients... But I'm thinking more and more to go this simple way. What do you think? Thanks in advance to you, StackOverflow people which have taken the time to read this huge question. I really had to explain the whole context if I want to get some help.

    Read the article

  • Problem in working with async and await?

    - by Vicky
    I am trying to upload files to Azure Blob Storage and after successful upload adding the filename to a list for my further operation. When i am doing synchronous it works fine but when i am doing async the error occured. Error : Collection was modified; enumeration operation may not execute. foreach(var file in files) { // ..... await blockBlob.UploadFromStreamAsync(fs); listOfMovedLabelFiles.Add(fileName); } if (listOfMovedLabelFiles.Count > 0) // error point { // my code for further operation } Is there any way to wait till all the async operations get completed.

    Read the article

  • These are few objective type questions which i was not able to find the solution [closed]

    - by Tarun
    1. Which of the following advantages does System.Collections.IDictionaryEnumerator provide over System.Collections.IEnumerator? a. It adds properties for direct access to both the Key and the Value b. It is optimized to handle the structure of a Dictionary. c. It provides properties to determine if the Dictionary is enumerated in Key or Value order d. It provides reverse lookup methods to distinguish a Key from a specific Value 2. When Implementing System.EnterpriseServices.ServicedComponent derived classes, which of the following statements are true? a. Enabling object pooling requires an attribute on the class and the enabling of pooling in the COM+ catalog. b. Methods can be configured to automatically mark a transaction as complete by the use of attributes. c. You can configure authentication using the AuthenticationOption when the ActivationMode is set to Library. d. You can control the lifecycle policy of an individual instance using the SetLifetimeService method. 3. Which of the following are true regarding event declaration in the code below? class Sample { event MyEventHandlerType MyEvent; } a. MyEventHandlerType must be derived from System.EventHandler or System.EventHandler<TEventArgs> b. MyEventHandlerType must take two parameters, the first of the type Object, and the second of a class derived from System.EventArgs c. MyEventHandlerType may have a non-void return type d. If MyEventHandlerType is a generic type, event declaration must use a specialization of that type. e. MyEventHandlerType cannot be declared static 4. Which of the following statements apply to developing .NET code, using .NET utilities that are available with the SDK or Visual Studio? a. Developers can create assemblies directly from the MSIL Source Code. b. Developers can examine PE header information in an assembly. c. Developers can generate XML Schemas from class definitions contained within an assembly. d. Developers can strip all meta-data from managed assemblies. e. Developers can split an assembly into multiple assemblies. 5. Which of the following characteristics do classes in the System.Drawing namespace such as Brush,Font,Pen, and Icon share? a. They encapsulate native resource and must be properly Disposed to prevent potential exhausting of resources. b. They are all MarshalByRef derived classes, but functionality across AppDomains has specific limitations. c. You can inherit from these classes to provide enhanced or customized functionality 6. Which of the following are required to be true by objects which are going to be used as keys in a System.Collections.HashTable? a. They must handle case-sensitivity identically in both the GetHashCode() and Equals() methods. b. Key objects must be immutable for the duration they are used within a HashTable. c. Get HashCode() must be overridden to provide the same result, given the same parameters, regardless of reference equalityl unless the HashTable constructor is provided with an IEqualityComparer parameter. d. Each Element in a HashTable is stored as a Key/Value pair of the type System.Collections.DictionaryElement e. All of the above 7. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. A Nullable type is a structure. c. An implicit conversion exists from any non-nullable value type to a nullable form of that type. d. An implicit conversion exists from any nullable value type to a non-nullable form of that type. e. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 8. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 9. Which of the following does using Initializer Syntax with a collection as shown below require? CollectionClass numbers = new CollectionClass { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; a. The Collection Class must implement System.Collections.Generic.ICollection<T> b. The Collection Class must implement System.Collections.Generic.IList<T> c. Each of the Items in the Initializer List will be passed to the Add<T>(T item) method d. The items in the initializer will be treated as an IEnumerable<T> and passed to the collection constructor+K110 10. What impact will using implicitly typed local variables as in the following example have? var sample = "Hello World"; a. The actual type is determined at compilation time, and has no impact on the runtime b. The actual type is determined at runtime, and late binding takes effect c. The actual type is based on the native VARIANT concept, and no binding to a specific type takes place. d. "var" itself is a specific type defined by the framework, and no special binding takes place 11. Which of the following is not supported by remoting object types? a. well-known singleton b. well-known single call c. client activated d. context-agile 12. In which of the following ways do structs differ from classes? a. Structs can not implement interfaces b. Structs cannot inherit from a base struct c. Structs cannot have events interfaces d. Structs cannot have virtual methods 13. Which of the following is not an unboxing conversion? a. void Sample1(object o) { int i = (int)o; } b. void Sample1(ValueType vt) { int i = (int)vt; } c. enum E { Hello, World} void Sample1(System.Enum et) { E e = (E) et; } d. interface I { int Value { get; set; } } void Sample1(I vt) { int i = vt.Value; } e. class C { public int Value { get; set; } } void Sample1(C vt) { int i = vt.Value; } 14. Which of the following are characteristics of the System.Threading.Timer class? a. The method provided by the TimerCallback delegate will always be invoked on the thread which created the timer. b. The thread which creates the timer must have a message processing loop (i.e. be considered a UI thread) c. The class contains protection to prevent reentrancy to the method provided by the TimerCallback delegate d. You can receive notification of an instance being Disposed by calling an overload of the Dispose method. 15. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 16. Which of the following scenarios are applicable to Window Workflow Foundation? a. Document-centric workflows b. Human workflows c. User-interface page flows d. Builtin support for communications across multiple applications and/or platforms e. All of the above 17. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 18 While using the capabilities supplied by the System.Messaging classes, which of the following are true? a. Information must be explicitly converted to/from a byte stream before it uses the MessageQueue class b. Invoking the MessageQueue.Send member defaults to using the System.Messaging.XmlMessageFormatter to serialize the object. c. Objects must be XMLSerializable in order to be transferred over a MessageQueue instance. d. The first entry in a MessageQueue must be removed from the queue before the next entry can be accessed e. Entries removed from a MessageQueue within the scope of a transaction, will be pushed back into the front of the queue if the transaction fails. 19. Which of the following are true about declarative attributes? a. They must be inherited from the System.Attribute. b. Attributes are instantiated at the same time as instances of the class to which they are applied. c. Attribute classes may be restricted to be applied only to application element types. d. By default, a given attribute may be applied multiple times to the same application element. 20. When using version 3.5 of the framework in applications which emit a dynamic code, which of the following are true? a. A Partial trust code can not emit and execute a code b. A Partial trust application must have the SecurityCriticalAttribute attribute have called Assert ReflectionEmit permission c. The generated code no more permissions than the assembly which emitted it. d. It can be executed by calling System.Reflection.Emit.DynamicMethod( string name, Type returnType, Type[] parameterTypes ) without any special permissions Within Windows Workflow Foundation, Compensating Actions are used for: a. provide a means to rollback a failed transaction b. provide a means to undo a successfully committed transaction later c. provide a means to terminate an in process transaction d. achieve load balancing by adapting to the current activity 21. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 22. Which of the following controls allows the use of XSL to transform XML content into formatted content? a. System.Web.UI.WebControls.Xml b. System.Web.UI.WebControls.Xslt c. System.Web.UI.WebControls.Substitution d. System.Web.UI.WebControls.Transform 23. To which of the following do automatic properties refer? a. You declare (explicitly or implicitly) the accessibility of the property and get and set accessors, but do not provide any implementation or backing field b. You attribute a member field so that the compiler will generate get and set accessors c. The compiler creates properties for your class based on class level attributes d. They are properties which are automatically invoked as part of the object construction process 24. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. An implicit conversion exists from any non-nullable value type to a nullable form of that type. c. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 25. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is accessible via reflection. c. The compiler generates a code that will store the information separately from the instance to ensure its security. 26. When using an implicitly typed array, which of the following is most appropriate? a. All elements in the initializer list must be of the same type. b. All elements in the initializer list must be implicitly convertible to a known type which is the actual type of at least one member in the initializer list c. All elements in the initializer list must be implicitly convertible to common type which is a base type of the items actually in the list 27. Which of the following is false about anonymous types? a. They can be derived from any reference type. b. Two anonymous types with the same named parameters in the same order declared in different classes have the same type. c. All properties of an anonymous type are read/write. 28. Which of the following are true about Extension methods. a. They can be declared either static or instance members b. They must be declared in the same assembly (but may be in different source files) c. Extension methods can be used to override existing instance methods d. Extension methods with the same signature for the same class may be declared in multiple namespaces without causing compilation errors

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 92 93 94 95 96 97 98 99 100 101 102 103  | Next Page >