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  • process.waitFor()

    - by ashwani66476
    Hello Team, I am using the below code in my application ... Process process = Runtime.getRuntime().exec( "perl " + perlScript + " " + project + " " + fileName); : : : result = process.waitFor(); : : and this result gives the code 2 every time.....while running the application. what could be the reason for the "reason code" ??? Thanks In Advance

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  • OverRiding Help

    - by user445714
    Few questions on over riding. I am interiting a method openRead from another class, the method is to be overridden so that the scanner class uses the provided delimiter pattern, which is referenced. I need to make use of the scanner class useDelmiter method method from another class [code] public boolean openRead() throws FileNotFoundException { sc = new Scanner(new File(fileName)); if (fileName != null) { return true; } else { return false; } } [/code] delimiter [code] protected final String DELIMITERS = "[\s[^'a-zA-Z]]"; [/code] I'm at a loss to how i over ride this using the constant delimiter.

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  • Two if conditions or one if with OR

    - by Ram
    I have a small doubt I have following code bool res= false; if(cond1) { res = true; } if(cond2) { res = true; } Instead of this if I put following code if(cond1 || cond2) { res = true; } Which code snippet will be more optimized? I believe it would be second one as I have avoided an If condition.

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  • Validate NSString

    - by Chris
    I am validating an NSString to ensure that the string does not contain apostrophes. The code I'm using to do this is NSCharacterSet * invalidNumberSet = [NSCharacterSet characterSetWithCharactersInString:@"'"]; NSScanner * scanner = [NSScanner scannerWithString:string]; NSString * scannerResult; [scanner setCharactersToBeSkipped:nil]; [scanner scanUpToCharactersFromSet:invalidNumberSet intoString:&scannerResult]; if(![string isEqualToString:scannerResult]) { return 2; } Returning 2 represents an error. This code works, except for the case where the string is an apostrophe. To get around this issue, I added the following code above the preceding block. if([string isEqualToString:@"'"]); { return 2; } This code is evaluating to true, regardless of the input. I need to either prevent the first block from crashing with the input of ', or get the second block to work. What am I missing?

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  • writing javascript div in html

    - by user333060
    i have put in my source code to show live twitter search result on my webpage. Although it shows the search result but when i open the source code of my webpage it don't shows the tweets text in my source code.iT DYNAMICALLY LOADS IT I GUESS. iS there a way out to fetch the content of div and write it with some functions like document.write or etc.

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  • Changing the value of a macro at run time

    - by BrandiNo
    I'm working in Visual Studio 2010, using C++ code. What I'm trying to do is change the value of a preprocessor directive during run time, not sure if it's possible but i've tried this.. somefile.h static int mValue = 0; #define POO = mValue; ... #if POO 0 //define class methods #else //define class methods differently } main.cpp main() { //Code calls constructor and methods allowed when POO is 0 //Code increments mValue //Code calls constructor and methods allowed when POO is 1 } How can POO be changed so that class objects uses a different implementation of other methods? Or if it's not possible, what's a another approach to this?

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  • Way to kill python thread from inside thread?

    - by user859434
    I have some python code that currently performs expensive computation by performing the computation in parallel through many threads. For a given time period, many threads are created and started on the fly that share the same code which is explicitly stated within the run method of the thread. My question is how do I stop/kill a thread at the end of its run method? (the run is only called once) I need to do this in order to create more threads for the next batch of computation. #Example class someThread(threading.Thread): def __init__(self): #some init code def run(self): #Explicitly Stated Code without constant loops #Something performed to stop/kill this thread

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  • Getting country calling prefix

    - by Telkitty
    Just wondering whether there are easy ways to retrieve country calling code from a user's phone. For example, my app would like to pre-fill country calling code for the users. If the user is located in the U.S. the code +1 will be returned, +83 for China, +61 for Australia etc. I had a look around but I could only see: NSLocale *locale = [NSLocale currentLocale]; NSString *countryCode = [locale objectForKey: NSLocaleCountryCnode]; Which returns the abbreviation for the country code, not the calling prefix? Help is appreciated!

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  • Periods in Javascript function definition (function window.onload(){}) [closed]

    - by nemec
    Possible Duplicate: JavaScript Function Syntax Explanation: function object.myFunction(){..} I've seen some (legacy) javascript code recently that looks like: function window.onload(){ // some code } This doesn't look like valid javascript to me since you can't have a period in an identifier, but it seems to work in IE8. I assume it's the equivalent of: window.onload = function(){} I've tried the same code in Chrome and IE9 and both of them raise syntax exceptions, so am I correct in thinking that this "feature" of IE8 is some non-standard function definition that should be replaced? The code in question is only sent to IE browsers, so that's probably why I haven't run into this issue before.

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  • How do I reference a control in a different thread?

    - by Testifier
    //button is clicked //worker starts private void processWorker_DoWork(object sender, DoWorkEventArgs e) { string code = DoLongWorkAndReturnCode(); if (code != 0) { MessageBox.Show("Error!"); EnableAllButtons(); // this is defined in the other thread and it's where i run into the error. } else { string code = DoAnotherLongProcessAndReturnCode(); if (code != 0) { MessageBox.Show("Error 2!"); EnableAllButtons(); // again, this is defined in the other thread } } } I'm running into a cross threading error because "EnableAllButtons()" is defined in a different thread. How do I go about enabling all buttons in one thread, from a different thread?

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  • A free standing ASP.NET Pager Web Control

    - by Rick Strahl
    Paging in ASP.NET has been relatively easy with stock controls supporting basic paging functionality. However, recently I built an MVC application and one of the things I ran into was that I HAD TO build manual paging support into a few of my pages. Dealing with list controls and rendering markup is easy enough, but doing paging is a little more involved. I ended up with a small but flexible component that can be dropped anywhere. As it turns out the task of creating a semi-generic Pager control for MVC was fairly easily. Now I’m back to working in Web Forms and thought to myself that the way I created the pager in MVC actually would also work in ASP.NET – in fact quite a bit easier since the whole thing can be conveniently wrapped up into an easily reusable control. A standalone pager would provider easier reuse in various pages and a more consistent pager display regardless of what kind of 'control’ the pager is associated with. Why a Pager Control? At first blush it might sound silly to create a new pager control – after all Web Forms has pretty decent paging support, doesn’t it? Well, sort of. Yes the GridView control has automatic paging built in and the ListView control has the related DataPager control. The built in ASP.NET paging has several issues though: Postback and JavaScript requirements If you look at paging links in ASP.NET they are always postback links with javascript:__doPostback() calls that go back to the server. While that works fine and actually has some benefit like the fact that paging saves changes to the page and post them back, it’s not very SEO friendly. Basically if you use javascript based navigation nosearch engine will follow the paging links which effectively cuts off list content on the first page. The DataPager control does support GET based links via the QueryStringParameter property, but the control is effectively tied to the ListView control (which is the only control that implements IPageableItemContainer). DataSource Controls required for Efficient Data Paging Retrieval The only way you can get paging to work efficiently where only the few records you display on the page are queried for and retrieved from the database you have to use a DataSource control - only the Linq and Entity DataSource controls  support this natively. While you can retrieve this data yourself manually, there’s no way to just assign the page number and render the pager based on this custom subset. Other than that default paging requires a full resultset for ASP.NET to filter the data and display only a subset which can be very resource intensive and wasteful if you’re dealing with largish resultsets (although I’m a firm believer in returning actually usable sets :-}). If you use your own business layer that doesn’t fit an ObjectDataSource you’re SOL. That’s a real shame too because with LINQ based querying it’s real easy to retrieve a subset of data that is just the data you want to display but the native Pager functionality doesn’t support just setting properties to display just the subset AFAIK. DataPager is not Free Standing The DataPager control is the closest thing to a decent Pager implementation that ASP.NET has, but alas it’s not a free standing component – it works off a related control and the only one that it effectively supports from the stock ASP.NET controls is the ListView control. This means you can’t use the same data pager formatting for a grid and a list view or vice versa and you’re always tied to the control. Paging Events In order to handle paging you have to deal with paging events. The events fire at specific time instances in the page pipeline and because of this you often have to handle data binding in a way to work around the paging events or else end up double binding your data sources based on paging. Yuk. Styling The GridView pager is a royal pain to beat into submission for styled rendering. The DataPager control has many more options and template layout and it renders somewhat cleaner, but it too is not exactly easy to get a decent display for. Not a Generic Solution The problem with the ASP.NET controls too is that it’s not generic. GridView, DataGrid use their own internal paging, ListView can use a DataPager and if you want to manually create data layout – well you’re on your own. IOW, depending on what you use you likely have very different looking Paging experiences. So, I figured I’ve struggled with this once too many and finally sat down and built a Pager control. The Pager Control My goal was to create a totally free standing control that has no dependencies on other controls and certainly no requirements for using DataSource controls. The idea is that you should be able to use this pager control without any sort of data requirements at all – you should just be able to set properties and be able to display a pager. The Pager control I ended up with has the following features: Completely free standing Pager control – no control or data dependencies Complete manual control – Pager can render without any data dependency Easy to use: Only need to set PageSize, ActivePage and TotalItems Supports optional filtering of IQueryable for efficient queries and Pager rendering Supports optional full set filtering of IEnumerable<T> and DataTable Page links are plain HTTP GET href Links Control automatically picks up Page links on the URL and assigns them (automatic page detection no page index changing events to hookup) Full CSS Styling support On the downside there’s no templating support for the control so the layout of the pager is relatively fixed. All elements however are stylable and there are options to control the text, and layout options such as whether to display first and last pages and the previous/next buttons and so on. To give you an idea what the pager looks like, here are two differently styled examples (all via CSS):   The markup for these two pagers looks like this: <ww:Pager runat="server" id="ItemPager" PageSize="5" PageLinkCssClass="gridpagerbutton" SelectedPageCssClass="gridpagerbutton-selected" PagesTextCssClass="gridpagertext" CssClass="gridpager" RenderContainerDiv="true" ContainerDivCssClass="gridpagercontainer" MaxPagesToDisplay="6" PagesText="Item Pages:" NextText="next" PreviousText="previous" /> <ww:Pager runat="server" id="ItemPager2" PageSize="5" RenderContainerDiv="true" MaxPagesToDisplay="6" /> The latter example uses default style settings so it there’s not much to set. The first example on the other hand explicitly assigns custom styles and overrides a few of the formatting options. Styling The styling is based on a number of CSS classes of which the the main pager, pagerbutton and pagerbutton-selected classes are the important ones. Other styles like pagerbutton-next/prev/first/last are based on the pagerbutton style. The default styling shown for the red outlined pager looks like this: .pagercontainer { margin: 20px 0; background: whitesmoke; padding: 5px; } .pager { float: right; font-size: 10pt; text-align: left; } .pagerbutton,.pagerbutton-selected,.pagertext { display: block; float: left; text-align: center; border: solid 2px maroon; min-width: 18px; margin-left: 3px; text-decoration: none; padding: 4px; } .pagerbutton-selected { font-size: 130%; font-weight: bold; color: maroon; border-width: 0px; background: khaki; } .pagerbutton-first { margin-right: 12px; } .pagerbutton-last,.pagerbutton-prev { margin-left: 12px; } .pagertext { border: none; margin-left: 30px; font-weight: bold; } .pagerbutton a { text-decoration: none; } .pagerbutton:hover { background-color: maroon; color: cornsilk; } .pagerbutton-prev { background-image: url(images/prev.png); background-position: 2px center; background-repeat: no-repeat; width: 35px; padding-left: 20px; } .pagerbutton-next { background-image: url(images/next.png); background-position: 40px center; background-repeat: no-repeat; width: 35px; padding-right: 20px; margin-right: 0px; } Yup that’s a lot of styling settings although not all of them are required. The key ones are pagerbutton, pager and pager selection. The others (which are implicitly created by the control based on the pagerbutton style) are for custom markup of the ‘special’ buttons. In my apps I tend to have two kinds of pages: Those that are associated with typical ‘grid’ displays that display purely tabular data and those that have a more looser list like layout. The two pagers shown above represent these two views and the pager and gridpager styles in my standard style sheet reflect these two styles. Configuring the Pager with Code Finally lets look at what it takes to hook up the pager. As mentioned in the highlights the Pager control is completely independent of other controls so if you just want to display a pager on its own it’s as simple as dropping the control and assigning the PageSize, ActivePage and either TotalPages or TotalItems. So for this markup: <ww:Pager runat="server" id="ItemPagerManual" PageSize="5" MaxPagesToDisplay="6" /> I can use code as simple as: ItemPagerManual.PageSize = 3; ItemPagerManual.ActivePage = 4;ItemPagerManual.TotalItems = 20; Note that ActivePage is not required - it will automatically use any Page=x query string value and assign it, although you can override it as I did above. TotalItems can be any value that you retrieve from a result set or manually assign as I did above. A more realistic scenario based on a LINQ to SQL IQueryable result is even easier. In this example, I have a UserControl that contains a ListView control that renders IQueryable data. I use a User Control here because there are different views the user can choose from with each view being a different user control. This incidentally also highlights one of the nice features of the pager: Because the pager is independent of the control I can put the pager on the host page instead of into each of the user controls. IOW, there’s only one Pager control, but there are potentially many user controls/listviews that hold the actual display data. The following code demonstrates how to use the Pager with an IQueryable that loads only the records it displays: protected voidPage_Load(objectsender, EventArgs e) {     Category = Request.Params["Category"] ?? string.Empty;     IQueryable<wws_Item> ItemList = ItemRepository.GetItemsByCategory(Category);     // Update the page and filter the list down     ItemList = ItemPager.FilterIQueryable<wws_Item>(ItemList); // Render user control with a list view Control ulItemList = LoadControl("~/usercontrols/" + App.Configuration.ItemListType + ".ascx"); ((IInventoryItemListControl)ulItemList).InventoryItemList = ItemList; phItemList.Controls.Add(ulItemList); // placeholder } The code uses a business object to retrieve Items by category as an IQueryable which means that the result is only an expression tree that hasn’t execute SQL yet and can be further filtered. I then pass this IQueryable to the FilterIQueryable() helper method of the control which does two main things: Filters the IQueryable to retrieve only the data displayed on the active page Sets the Totaltems property and calculates TotalPages on the Pager and that’s it! When the Pager renders it uses those values, plus the PageSize and ActivePage properties to render the Pager. In addition to IQueryable there are also filter methods for IEnumerable<T> and DataTable, but these versions just filter the data by removing rows/items from the entire already retrieved data. Output Generated and Paging Links The output generated creates pager links as plain href links. Here’s what the output looks like: <div id="ItemPager" class="pagercontainer"> <div class="pager"> <span class="pagertext">Pages: </span><a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=1" class="pagerbutton" />1</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=2" class="pagerbutton" />2</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=3" class="pagerbutton" />3</a> <span class="pagerbutton-selected">4</span> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=5" class="pagerbutton" />5</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=6" class="pagerbutton" />6</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=20" class="pagerbutton pagerbutton-last" />20</a>&nbsp;<a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=3" class="pagerbutton pagerbutton-prev" />Prev</a>&nbsp;<a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=5" class="pagerbutton pagerbutton-next" />Next</a></div> <br clear="all" /> </div> </div> The links point back to the current page and simply append a Page= page link into the page. When the page gets reloaded with the new page number the pager automatically detects the page number and automatically assigns the ActivePage property which results in the appropriate page to be displayed. The code shown in the previous section is all that’s needed to handle paging. Note that HTTP GET based paging is different than the Postback paging ASP.NET uses by default. Postback paging preserves modified page content when clicking on pager buttons, but this control will simply load a new page – no page preservation at this time. The advantage of not using Postback paging is that the URLs generated are plain HTML links that a search engine can follow where __doPostback() links are not. Pager with a Grid The pager also works in combination with grid controls so it’s easy to bypass the grid control’s paging features if desired. In the following example I use a gridView control and binds it to a DataTable result which is also filterable by the Pager control. The very basic plain vanilla ASP.NET grid markup looks like this: <div style="width: 600px; margin: 0 auto;padding: 20px; "> <asp:DataGrid runat="server" AutoGenerateColumns="True" ID="gdItems" CssClass="blackborder" style="width: 600px;"> <AlternatingItemStyle CssClass="gridalternate" /> <HeaderStyle CssClass="gridheader" /> </asp:DataGrid> <ww:Pager runat="server" ID="Pager" CssClass="gridpager" ContainerDivCssClass="gridpagercontainer" PageLinkCssClass="gridpagerbutton" SelectedPageCssClass="gridpagerbutton-selected" PageSize="8" RenderContainerDiv="true" MaxPagesToDisplay="6" /> </div> and looks like this when rendered: using custom set of CSS styles. The code behind for this code is also very simple: protected void Page_Load(object sender, EventArgs e) { string category = Request.Params["category"] ?? ""; busItem itemRep = WebStoreFactory.GetItem(); var items = itemRep.GetItemsByCategory(category) .Select(itm => new {Sku = itm.Sku, Description = itm.Description}); // run query into a DataTable for demonstration DataTable dt = itemRep.Converter.ToDataTable(items,"TItems"); // Remove all items not on the current page dt = Pager.FilterDataTable(dt,0); // bind and display gdItems.DataSource = dt; gdItems.DataBind(); } A little contrived I suppose since the list could already be bound from the list of elements, but this is to demonstrate that you can also bind against a DataTable if your business layer returns those. Unfortunately there’s no way to filter a DataReader as it’s a one way forward only reader and the reader is required by the DataSource to perform the bindings.  However, you can still use a DataReader as long as your business logic filters the data prior to rendering and provides a total item count (most likely as a second query). Control Creation The control itself is a pretty brute force ASP.NET control. Nothing clever about this other than some basic rendering logic and some simple calculations and update routines to determine which buttons need to be shown. You can take a look at the full code from the West Wind Web Toolkit’s Repository (note there are a few dependencies). To give you an idea how the control works here is the Render() method: /// <summary> /// overridden to handle custom pager rendering for runtime and design time /// </summary> /// <param name="writer"></param> protected override void Render(HtmlTextWriter writer) { base.Render(writer); if (TotalPages == 0 && TotalItems > 0) TotalPages = CalculateTotalPagesFromTotalItems(); if (DesignMode) TotalPages = 10; // don't render pager if there's only one page if (TotalPages < 2) return; if (RenderContainerDiv) { if (!string.IsNullOrEmpty(ContainerDivCssClass)) writer.AddAttribute("class", ContainerDivCssClass); writer.RenderBeginTag("div"); } // main pager wrapper writer.WriteBeginTag("div"); writer.AddAttribute("id", this.ClientID); if (!string.IsNullOrEmpty(CssClass)) writer.WriteAttribute("class", this.CssClass); writer.Write(HtmlTextWriter.TagRightChar + "\r\n"); // Pages Text writer.WriteBeginTag("span"); if (!string.IsNullOrEmpty(PagesTextCssClass)) writer.WriteAttribute("class", PagesTextCssClass); writer.Write(HtmlTextWriter.TagRightChar); writer.Write(this.PagesText); writer.WriteEndTag("span"); // if the base url is empty use the current URL FixupBaseUrl(); // set _startPage and _endPage ConfigurePagesToRender(); // write out first page link if (ShowFirstAndLastPageLinks && _startPage != 1) { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-first"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write("1"); writer.WriteEndTag("a"); writer.Write("&nbsp;"); } // write out all the page links for (int i = _startPage; i < _endPage + 1; i++) { if (i == ActivePage) { writer.WriteBeginTag("span"); if (!string.IsNullOrEmpty(SelectedPageCssClass)) writer.WriteAttribute("class", SelectedPageCssClass); writer.Write(HtmlTextWriter.TagRightChar); writer.Write(i.ToString()); writer.WriteEndTag("span"); } else { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, i.ToString()).TrimEnd('&'); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(i.ToString()); writer.WriteEndTag("a"); } writer.Write("\r\n"); } // write out last page link if (ShowFirstAndLastPageLinks && _endPage < TotalPages) { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, TotalPages.ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-last"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(TotalPages.ToString()); writer.WriteEndTag("a"); } // Previous link if (ShowPreviousNextLinks && !string.IsNullOrEmpty(PreviousText) && ActivePage > 1) { writer.Write("&nbsp;"); writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (ActivePage - 1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-prev"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(PreviousText); writer.WriteEndTag("a"); } // Next link if (ShowPreviousNextLinks && !string.IsNullOrEmpty(NextText) && ActivePage < TotalPages) { writer.Write("&nbsp;"); writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (ActivePage + 1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-next"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(NextText); writer.WriteEndTag("a"); } writer.WriteEndTag("div"); if (RenderContainerDiv) { if (RenderContainerDivBreak) writer.Write("<br clear=\"all\" />\r\n"); writer.WriteEndTag("div"); } } As I said pretty much brute force rendering based on the control’s property settings of which there are quite a few: You can also see the pager in the designer above. unfortunately the VS designer (both 2010 and 2008) fails to render the float: left CSS styles properly and starts wrapping after margins are applied in the special buttons. Not a big deal since VS does at least respect the spacing (the floated elements overlay). Then again I’m not using the designer anyway :-}. Filtering Data What makes the Pager easy to use is the filter methods built into the control. While this functionality is clearly not the most politically correct design choice as it violates separation of concerns, it’s very useful for typical pager operation. While I actually have filter methods that do something similar in my business layer, having it exposed on the control makes the control a lot more useful for typical databinding scenarios. Of course these methods are optional – if you have a business layer that can provide filtered page queries for you can use that instead and assign the TotalItems property manually. There are three filter method types available for IQueryable, IEnumerable and for DataTable which tend to be the most common use cases in my apps old and new. The IQueryable version is pretty simple as it can simply rely on on .Skip() and .Take() with LINQ: /// <summary> /// <summary> /// Queries the database for the ActivePage applied manually /// or from the Request["page"] variable. This routine /// figures out and sets TotalPages, ActivePage and /// returns a filtered subset IQueryable that contains /// only the items from the ActivePage. /// </summary> /// <param name="query"></param> /// <param name="activePage"> /// The page you want to display. Sets the ActivePage property when passed. /// Pass 0 or smaller to use ActivePage setting. /// </param> /// <returns></returns> public IQueryable<T> FilterIQueryable<T>(IQueryable<T> query, int activePage) where T : class, new() { ActivePage = activePage < 1 ? ActivePage : activePage; if (ActivePage < 1) ActivePage = 1; TotalItems = query.Count(); if (TotalItems <= PageSize) { ActivePage = 1; TotalPages = 1; return query; } int skip = ActivePage - 1; if (skip > 0) query = query.Skip(skip * PageSize); _TotalPages = CalculateTotalPagesFromTotalItems(); return query.Take(PageSize); } The IEnumerable<T> version simply  converts the IEnumerable to an IQuerable and calls back into this method for filtering. The DataTable version requires a little more work to manually parse and filter records (I didn’t want to add the Linq DataSetExtensions assembly just for this): /// <summary> /// Filters a data table for an ActivePage. /// /// Note: Modifies the data set permanently by remove DataRows /// </summary> /// <param name="dt">Full result DataTable</param> /// <param name="activePage">Page to display. 0 to use ActivePage property </param> /// <returns></returns> public DataTable FilterDataTable(DataTable dt, int activePage) { ActivePage = activePage < 1 ? ActivePage : activePage; if (ActivePage < 1) ActivePage = 1; TotalItems = dt.Rows.Count; if (TotalItems <= PageSize) { ActivePage = 1; TotalPages = 1; return dt; } int skip = ActivePage - 1; if (skip > 0) { for (int i = 0; i < skip * PageSize; i++ ) dt.Rows.RemoveAt(0); } while(dt.Rows.Count > PageSize) dt.Rows.RemoveAt(PageSize); return dt; } Using the Pager Control The pager as it is is a first cut I built a couple of weeks ago and since then have been tweaking a little as part of an internal project I’m working on. I’ve replaced a bunch of pagers on various older pages with this pager without any issues and have what now feels like a more consistent user interface where paging looks and feels the same across different controls. As a bonus I’m only loading the data from the database that I need to display a single page. With the preset class tags applied too adding a pager is now as easy as dropping the control and adding the style sheet for styling to be consistent – no fuss, no muss. Schweet. Hopefully some of you may find this as useful as I have or at least as a baseline to build ontop of… Resources The Pager is part of the West Wind Web & Ajax Toolkit Pager.cs Source Code (some toolkit dependencies) Westwind.css base stylesheet with .pager and .gridpager styles Pager Example Page © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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  • Version Assemblies with TFS 2010 Continuous Integration

    - by Steve Michelotti
    When I first heard that TFS 2010 had moved to Workflow Foundation for Team Build, I was *extremely* skeptical. I’ve loved MSBuild and didn’t quite understand the reasons for this change. In fact, given that I’ve been exclusively using Cruise Control for Continuous Integration (CI) for the last 5+ years of my career, I was skeptical of TFS for CI in general. However, after going through the learning process for TFS 2010 recently, I’m starting to become a believer. I’m also starting to see some of the benefits with Workflow Foundation for the overall processing because it gives you constructs not available in MSBuild such as parallel tasks, better control flow constructs, and a slightly better customization story. The first customization I had to make to the build process was to version the assemblies of my solution. This is not new. In fact, I’d recommend reading Mike Fourie’s well known post on Versioning Code in TFS before you get started. This post describes several foundational aspects of versioning assemblies regardless of your version of TFS. The main points are: 1) don’t use source control operations for your version file, 2) use a schema like <Major>.<Minor>.<IncrementalNumber>.0, and 3) do not keep AssemblyVersion and AssemblyFileVersion in sync. To do this in TFS 2010, the best post I’ve found has been Jim Lamb’s post of building a custom TFS 2010 workflow activity. Overall, this post is excellent but the primary issue I have with it is that the assembly version numbers produced are based in a date and look like this: “2010.5.15.1”. This is definitely not what I want. I want to be able to communicate to the developers and stakeholders that we are producing the “1.1 release” or “1.2 release” – which would have an assembly version number of “1.1.317.0” for example. In this post, I’ll walk through the process of customizing the assembly version number based on this method – customizing the concepts in Lamb’s post to suit my needs. I’ll also be combining this with the concepts of Fourie’s post – particularly with regards to the standards around how to version the assemblies. The first thing I’ll do is add a file called SolutionAssemblyVersionInfo.cs to the root of my solution that looks like this: 1: using System; 2: using System.Reflection; 3: [assembly: AssemblyVersion("1.1.0.0")] 4: [assembly: AssemblyFileVersion("1.1.0.0")] I’ll then add that file as a Visual Studio link file to each project in my solution by right-clicking the project, “Add – Existing Item…” then when I click the SolutionAssemblyVersionInfo.cs file, making sure I “Add As Link”: Now the Solution Explorer will show our file. We can see that it’s a “link” file because of the black arrow in the icon within all our projects. Of course you’ll need to remove the AssemblyVersion and AssemblyFileVersion attributes from the AssemblyInfo.cs files to avoid the duplicate attributes since they now leave in the SolutionAssemblyVersionInfo.cs file. This is an extremely common technique so that all the projects in our solution can be versioned as a unit. At this point, we’re ready to write our custom activity. The primary consideration is that I want the developer and/or tech lead to be able to easily be in control of the Major.Minor and then I want the CI process to add the third number with a unique incremental number. We’ll leave the fourth position always “0” for now – it’s held in reserve in case the day ever comes where we need to do an emergency patch to Production based on a branched version.   Writing the Custom Workflow Activity Similar to Lamb’s post, I’m going to write two custom workflow activities. The “outer” activity (a xaml activity) will be pretty straight forward. It will check if the solution version file exists in the solution root and, if so, delegate the replacement of version to the AssemblyVersionInfo activity which is a CodeActivity highlighted in red below:   Notice that the arguments of this activity are the “solutionVersionFile” and “tfsBuildNumber” which will be passed in. The tfsBuildNumber passed in will look something like this: “CI_MyApplication.4” and we’ll need to grab the “4” (i.e., the incremental revision number) and put that in the third position. Then we’ll need to honor whatever was specified for Major.Minor in the SolutionAssemblyVersionInfo.cs file. For example, if the SolutionAssemblyVersionInfo.cs file had “1.1.0.0” for the AssemblyVersion (as shown in the first code block near the beginning of this post), then we want to resulting file to have “1.1.4.0”. Before we do anything, let’s put together a unit test for all this so we can know if we get it right: 1: [TestMethod] 2: public void Assembly_version_should_be_parsed_correctly_from_build_name() 3: { 4: // arrange 5: const string versionFile = "SolutionAssemblyVersionInfo.cs"; 6: WriteTestVersionFile(versionFile); 7: var activity = new VersionAssemblies(); 8: var arguments = new Dictionary<string, object> { 9: { "tfsBuildNumber", "CI_MyApplication.4"}, 10: { "solutionVersionFile", versionFile} 11: }; 12:   13: // act 14: var result = WorkflowInvoker.Invoke(activity, arguments); 15:   16: // assert 17: Assert.AreEqual("1.2.4.0", (string)result["newAssemblyFileVersion"]); 18: var lines = File.ReadAllLines(versionFile); 19: Assert.IsTrue(lines.Contains("[assembly: AssemblyVersion(\"1.2.0.0\")]")); 20: Assert.IsTrue(lines.Contains("[assembly: AssemblyFileVersion(\"1.2.4.0\")]")); 21: } 22: 23: private void WriteTestVersionFile(string versionFile) 24: { 25: var fileContents = "using System.Reflection;\n" + 26: "[assembly: AssemblyVersion(\"1.2.0.0\")]\n" + 27: "[assembly: AssemblyFileVersion(\"1.2.0.0\")]"; 28: File.WriteAllText(versionFile, fileContents); 29: }   At this point, the code for our AssemblyVersion activity is pretty straight forward: 1: [BuildActivity(HostEnvironmentOption.Agent)] 2: public class AssemblyVersionInfo : CodeActivity 3: { 4: [RequiredArgument] 5: public InArgument<string> FileName { get; set; } 6:   7: [RequiredArgument] 8: public InArgument<string> TfsBuildNumber { get; set; } 9:   10: public OutArgument<string> NewAssemblyFileVersion { get; set; } 11:   12: protected override void Execute(CodeActivityContext context) 13: { 14: var solutionVersionFile = this.FileName.Get(context); 15: 16: // Ensure that the file is writeable 17: var fileAttributes = File.GetAttributes(solutionVersionFile); 18: File.SetAttributes(solutionVersionFile, fileAttributes & ~FileAttributes.ReadOnly); 19:   20: // Prepare assembly versions 21: var majorMinor = GetAssemblyMajorMinorVersionBasedOnExisting(solutionVersionFile); 22: var newBuildNumber = GetNewBuildNumber(this.TfsBuildNumber.Get(context)); 23: var newAssemblyVersion = string.Format("{0}.{1}.0.0", majorMinor.Item1, majorMinor.Item2); 24: var newAssemblyFileVersion = string.Format("{0}.{1}.{2}.0", majorMinor.Item1, majorMinor.Item2, newBuildNumber); 25: this.NewAssemblyFileVersion.Set(context, newAssemblyFileVersion); 26:   27: // Perform the actual replacement 28: var contents = this.GetFileContents(newAssemblyVersion, newAssemblyFileVersion); 29: File.WriteAllText(solutionVersionFile, contents); 30:   31: // Restore the file's original attributes 32: File.SetAttributes(solutionVersionFile, fileAttributes); 33: } 34:   35: #region Private Methods 36:   37: private string GetFileContents(string newAssemblyVersion, string newAssemblyFileVersion) 38: { 39: var cs = new StringBuilder(); 40: cs.AppendLine("using System.Reflection;"); 41: cs.AppendFormat("[assembly: AssemblyVersion(\"{0}\")]", newAssemblyVersion); 42: cs.AppendLine(); 43: cs.AppendFormat("[assembly: AssemblyFileVersion(\"{0}\")]", newAssemblyFileVersion); 44: return cs.ToString(); 45: } 46:   47: private Tuple<string, string> GetAssemblyMajorMinorVersionBasedOnExisting(string filePath) 48: { 49: var lines = File.ReadAllLines(filePath); 50: var versionLine = lines.Where(x => x.Contains("AssemblyVersion")).FirstOrDefault(); 51:   52: if (versionLine == null) 53: { 54: throw new InvalidOperationException("File does not contain [assembly: AssemblyVersion] attribute"); 55: } 56:   57: return ExtractMajorMinor(versionLine); 58: } 59:   60: private static Tuple<string, string> ExtractMajorMinor(string versionLine) 61: { 62: var firstQuote = versionLine.IndexOf('"') + 1; 63: var secondQuote = versionLine.IndexOf('"', firstQuote); 64: var version = versionLine.Substring(firstQuote, secondQuote - firstQuote); 65: var versionParts = version.Split('.'); 66: return new Tuple<string, string>(versionParts[0], versionParts[1]); 67: } 68:   69: private string GetNewBuildNumber(string buildName) 70: { 71: return buildName.Substring(buildName.LastIndexOf(".") + 1); 72: } 73:   74: #endregion 75: }   At this point the final step is to incorporate this activity into the overall build template. Make a copy of the DefaultTempate.xaml – we’ll call it DefaultTemplateWithVersioning.xaml. Before the build and labeling happens, drag the VersionAssemblies activity in. Then set the LabelName variable to “BuildDetail.BuildDefinition.Name + "-" + newAssemblyFileVersion since the newAssemblyFileVersion was produced by our activity.   Configuring CI Once you add your solution to source control, you can configure CI with the build definition window as shown here. The main difference is that we’ll change the Process tab to reflect a different build number format and choose our custom build process file:   When the build completes, we’ll see the name of our project with the unique revision number:   If we look at the detailed build log for the latest build, we’ll see the label being created with our custom task:     We can now look at the history labels in TFS and see the project name with the labels (the Assignment activity I added to the workflow):   Finally, if we look at the physical assemblies that are produced, we can right-click on any assembly in Windows Explorer and see the assembly version in its properties:   Full Traceability We now have full traceability for our code. There will never be a question of what code was deployed to Production. You can always see the assembly version in the properties of the physical assembly. That can be traced back to a label in TFS where the unique revision number matches. The label in TFS gives you the complete snapshot of the code in your source control repository at the time the code was built. This type of process for full traceability has been used for many years for CI – in fact, I’ve done similar things with CCNet and SVN for quite some time. This is simply the TFS implementation of that pattern. The new features that TFS 2010 give you to make these types of customizations in your build process are quite easy once you get over the initial curve.

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  • Upload File to Windows Azure Blob in Chunks through ASP.NET MVC, JavaScript and HTML5

    - by Shaun
    Originally posted on: http://geekswithblogs.net/shaunxu/archive/2013/07/01/upload-file-to-windows-azure-blob-in-chunks-through-asp.net.aspxMany people are using Windows Azure Blob Storage to store their data in the cloud. Blob storage provides 99.9% availability with easy-to-use API through .NET SDK and HTTP REST. For example, we can store JavaScript files, images, documents in blob storage when we are building an ASP.NET web application on a Web Role in Windows Azure. Or we can store our VHD files in blob and mount it as a hard drive in our cloud service. If you are familiar with Windows Azure, you should know that there are two kinds of blob: page blob and block blob. The page blob is optimized for random read and write, which is very useful when you need to store VHD files. The block blob is optimized for sequential/chunk read and write, which has more common usage. Since we can upload block blob in blocks through BlockBlob.PutBlock, and them commit them as a whole blob with invoking the BlockBlob.PutBlockList, it is very powerful to upload large files, as we can upload blocks in parallel, and provide pause-resume feature. There are many documents, articles and blog posts described on how to upload a block blob. Most of them are focus on the server side, which means when you had received a big file, stream or binaries, how to upload them into blob storage in blocks through .NET SDK.  But the problem is, how can we upload these large files from client side, for example, a browser. This questioned to me when I was working with a Chinese customer to help them build a network disk production on top of azure. The end users upload their files from the web portal, and then the files will be stored in blob storage from the Web Role. My goal is to find the best way to transform the file from client (end user’s machine) to the server (Web Role) through browser. In this post I will demonstrate and describe what I had done, to upload large file in chunks with high speed, and save them as blocks into Windows Azure Blob Storage.   Traditional Upload, Works with Limitation The simplest way to implement this requirement is to create a web page with a form that contains a file input element and a submit button. 1: @using (Html.BeginForm("About", "Index", FormMethod.Post, new { enctype = "multipart/form-data" })) 2: { 3: <input type="file" name="file" /> 4: <input type="submit" value="upload" /> 5: } And then in the backend controller, we retrieve the whole content of this file and upload it in to the blob storage through .NET SDK. We can split the file in blocks and upload them in parallel and commit. The code had been well blogged in the community. 1: [HttpPost] 2: public ActionResult About(HttpPostedFileBase file) 3: { 4: var container = _client.GetContainerReference("test"); 5: container.CreateIfNotExists(); 6: var blob = container.GetBlockBlobReference(file.FileName); 7: var blockDataList = new Dictionary<string, byte[]>(); 8: using (var stream = file.InputStream) 9: { 10: var blockSizeInKB = 1024; 11: var offset = 0; 12: var index = 0; 13: while (offset < stream.Length) 14: { 15: var readLength = Math.Min(1024 * blockSizeInKB, (int)stream.Length - offset); 16: var blockData = new byte[readLength]; 17: offset += stream.Read(blockData, 0, readLength); 18: blockDataList.Add(Convert.ToBase64String(BitConverter.GetBytes(index)), blockData); 19:  20: index++; 21: } 22: } 23:  24: Parallel.ForEach(blockDataList, (bi) => 25: { 26: blob.PutBlock(bi.Key, new MemoryStream(bi.Value), null); 27: }); 28: blob.PutBlockList(blockDataList.Select(b => b.Key).ToArray()); 29:  30: return RedirectToAction("About"); 31: } This works perfect if we selected an image, a music or a small video to upload. But if I selected a large file, let’s say a 6GB HD-movie, after upload for about few minutes the page will be shown as below and the upload will be terminated. In ASP.NET there is a limitation of request length and the maximized request length is defined in the web.config file. It’s a number which less than about 4GB. So if we want to upload a really big file, we cannot simply implement in this way. Also, in Windows Azure, a cloud service network load balancer will terminate the connection if exceed the timeout period. From my test the timeout looks like 2 - 3 minutes. Hence, when we need to upload a large file we cannot just use the basic HTML elements. Besides the limitation mentioned above, the simple HTML file upload cannot provide rich upload experience such as chunk upload, pause and pause-resume. So we need to find a better way to upload large file from the client to the server.   Upload in Chunks through HTML5 and JavaScript In order to break those limitation mentioned above we will try to upload the large file in chunks. This takes some benefit to us such as - No request size limitation: Since we upload in chunks, we can define the request size for each chunks regardless how big the entire file is. - No timeout problem: The size of chunks are controlled by us, which means we should be able to make sure request for each chunk upload will not exceed the timeout period of both ASP.NET and Windows Azure load balancer. It was a big challenge to upload big file in chunks until we have HTML5. There are some new features and improvements introduced in HTML5 and we will use them to implement our solution.   In HTML5, the File interface had been improved with a new method called “slice”. It can be used to read part of the file by specifying the start byte index and the end byte index. For example if the entire file was 1024 bytes, file.slice(512, 768) will read the part of this file from the 512nd byte to 768th byte, and return a new object of interface called "Blob”, which you can treat as an array of bytes. In fact,  a Blob object represents a file-like object of immutable, raw data. The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system. For more information about the Blob please refer here. File and Blob is very useful to implement the chunk upload. We will use File interface to represent the file the user selected from the browser and then use File.slice to read the file in chunks in the size we wanted. For example, if we wanted to upload a 10MB file with 512KB chunks, then we can read it in 512KB blobs by using File.slice in a loop.   Assuming we have a web page as below. User can select a file, an input box to specify the block size in KB and a button to start upload. 1: <div> 2: <input type="file" id="upload_files" name="files[]" /><br /> 3: Block Size: <input type="number" id="block_size" value="512" name="block_size" />KB<br /> 4: <input type="button" id="upload_button_blob" name="upload" value="upload (blob)" /> 5: </div> Then we can have the JavaScript function to upload the file in chunks when user clicked the button. 1: <script type="text/javascript"> 1: 2: $(function () { 3: $("#upload_button_blob").click(function () { 4: }); 5: });</script> Firstly we need to ensure the client browser supports the interfaces we are going to use. Just try to invoke the File, Blob and FormData from the “window” object. If any of them is “undefined” the condition result will be “false” which means your browser doesn’t support these premium feature and it’s time for you to get your browser updated. FormData is another new feature we are going to use in the future. It could generate a temporary form for us. We will use this interface to create a form with chunk and associated metadata when invoked the service through ajax. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: if (window.File && window.Blob && window.FormData) { 4: alert("Your brwoser is awesome, let's rock!"); 5: } 6: else { 7: alert("Oh man plz update to a modern browser before try is cool stuff out."); 8: return; 9: } 10: }); Each browser supports these interfaces by their own implementation and currently the Blob, File and File.slice are supported by Chrome 21, FireFox 13, IE 10, Opera 12 and Safari 5.1 or higher. After that we worked on the files the user selected one by one since in HTML5, user can select multiple files in one file input box. 1: var files = $("#upload_files")[0].files; 2: for (var i = 0; i < files.length; i++) { 3: var file = files[i]; 4: var fileSize = file.size; 5: var fileName = file.name; 6: } Next, we calculated the start index and end index for each chunks based on the size the user specified from the browser. We put them into an array with the file name and the index, which will be used when we upload chunks into Windows Azure Blob Storage as blocks since we need to specify the target blob name and the block index. At the same time we will store the list of all indexes into another variant which will be used to commit blocks into blob in Azure Storage once all chunks had been uploaded successfully. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10:  11: // calculate the start and end byte index for each blocks(chunks) 12: // with the index, file name and index list for future using 13: var blockSizeInKB = $("#block_size").val(); 14: var blockSize = blockSizeInKB * 1024; 15: var blocks = []; 16: var offset = 0; 17: var index = 0; 18: var list = ""; 19: while (offset < fileSize) { 20: var start = offset; 21: var end = Math.min(offset + blockSize, fileSize); 22:  23: blocks.push({ 24: name: fileName, 25: index: index, 26: start: start, 27: end: end 28: }); 29: list += index + ","; 30:  31: offset = end; 32: index++; 33: } 34: } 35: }); Now we have all chunks’ information ready. The next step should be upload them one by one to the server side, and at the server side when received a chunk it will upload as a block into Blob Storage, and finally commit them with the index list through BlockBlobClient.PutBlockList. But since all these invokes are ajax calling, which means not synchronized call. So we need to introduce a new JavaScript library to help us coordinate the asynchronize operation, which named “async.js”. You can download this JavaScript library here, and you can find the document here. I will not explain this library too much in this post. We will put all procedures we want to execute as a function array, and pass into the proper function defined in async.js to let it help us to control the execution sequence, in series or in parallel. Hence we will define an array and put the function for chunk upload into this array. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4:  5: // start to upload each files in chunks 6: var files = $("#upload_files")[0].files; 7: for (var i = 0; i < files.length; i++) { 8: var file = files[i]; 9: var fileSize = file.size; 10: var fileName = file.name; 11: // calculate the start and end byte index for each blocks(chunks) 12: // with the index, file name and index list for future using 13: ... ... 14:  15: // define the function array and push all chunk upload operation into this array 16: blocks.forEach(function (block) { 17: putBlocks.push(function (callback) { 18: }); 19: }); 20: } 21: }); 22: }); As you can see, I used File.slice method to read each chunks based on the start and end byte index we calculated previously, and constructed a temporary HTML form with the file name, chunk index and chunk data through another new feature in HTML5 named FormData. Then post this form to the backend server through jQuery.ajax. This is the key part of our solution. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: blocks.forEach(function (block) { 15: putBlocks.push(function (callback) { 16: // load blob based on the start and end index for each chunks 17: var blob = file.slice(block.start, block.end); 18: // put the file name, index and blob into a temporary from 19: var fd = new FormData(); 20: fd.append("name", block.name); 21: fd.append("index", block.index); 22: fd.append("file", blob); 23: // post the form to backend service (asp.net mvc controller action) 24: $.ajax({ 25: url: "/Home/UploadInFormData", 26: data: fd, 27: processData: false, 28: contentType: "multipart/form-data", 29: type: "POST", 30: success: function (result) { 31: if (!result.success) { 32: alert(result.error); 33: } 34: callback(null, block.index); 35: } 36: }); 37: }); 38: }); 39: } 40: }); Then we will invoke these functions one by one by using the async.js. And once all functions had been executed successfully I invoked another ajax call to the backend service to commit all these chunks (blocks) as the blob in Windows Azure Storage. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.series(putBlocks, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: }); That’s all in the client side. The outline of our logic would be - Calculate the start and end byte index for each chunks based on the block size. - Defined the functions of reading the chunk form file and upload the content to the backend service through ajax. - Execute the functions defined in previous step with “async.js”. - Commit the chunks by invoking the backend service in Windows Azure Storage finally.   Save Chunks as Blocks into Blob Storage In above we finished the client size JavaScript code. It uploaded the file in chunks to the backend service which we are going to implement in this step. We will use ASP.NET MVC as our backend service, and it will receive the chunks, upload into Windows Azure Bob Storage in blocks, then finally commit as one blob. As in the client side we uploaded chunks by invoking the ajax call to the URL "/Home/UploadInFormData", I created a new action under the Index controller and it only accepts HTTP POST request. 1: [HttpPost] 2: public JsonResult UploadInFormData() 3: { 4: var error = string.Empty; 5: try 6: { 7: } 8: catch (Exception e) 9: { 10: error = e.ToString(); 11: } 12:  13: return new JsonResult() 14: { 15: Data = new 16: { 17: success = string.IsNullOrWhiteSpace(error), 18: error = error 19: } 20: }; 21: } Then I retrieved the file name, index and the chunk content from the Request.Form object, which was passed from our client side. And then, used the Windows Azure SDK to create a blob container (in this case we will use the container named “test”.) and create a blob reference with the blob name (same as the file name). Then uploaded the chunk as a block of this blob with the index, since in Blob Storage each block must have an index (ID) associated with so that finally we can put all blocks as one blob by specifying their block ID list. 1: [HttpPost] 2: public JsonResult UploadInFormData() 3: { 4: var error = string.Empty; 5: try 6: { 7: var name = Request.Form["name"]; 8: var index = int.Parse(Request.Form["index"]); 9: var file = Request.Files[0]; 10: var id = Convert.ToBase64String(BitConverter.GetBytes(index)); 11:  12: var container = _client.GetContainerReference("test"); 13: container.CreateIfNotExists(); 14: var blob = container.GetBlockBlobReference(name); 15: blob.PutBlock(id, file.InputStream, null); 16: } 17: catch (Exception e) 18: { 19: error = e.ToString(); 20: } 21:  22: return new JsonResult() 23: { 24: Data = new 25: { 26: success = string.IsNullOrWhiteSpace(error), 27: error = error 28: } 29: }; 30: } Next, I created another action to commit the blocks into blob once all chunks had been uploaded. Similarly, I retrieved the blob name from the Request.Form. I also retrieved the chunks ID list, which is the block ID list from the Request.Form in a string format, split them as a list, then invoked the BlockBlob.PutBlockList method. After that our blob will be shown in the container and ready to be download. 1: [HttpPost] 2: public JsonResult Commit() 3: { 4: var error = string.Empty; 5: try 6: { 7: var name = Request.Form["name"]; 8: var list = Request.Form["list"]; 9: var ids = list 10: .Split(',') 11: .Where(id => !string.IsNullOrWhiteSpace(id)) 12: .Select(id => Convert.ToBase64String(BitConverter.GetBytes(int.Parse(id)))) 13: .ToArray(); 14:  15: var container = _client.GetContainerReference("test"); 16: container.CreateIfNotExists(); 17: var blob = container.GetBlockBlobReference(name); 18: blob.PutBlockList(ids); 19: } 20: catch (Exception e) 21: { 22: error = e.ToString(); 23: } 24:  25: return new JsonResult() 26: { 27: Data = new 28: { 29: success = string.IsNullOrWhiteSpace(error), 30: error = error 31: } 32: }; 33: } Now we finished all code we need. The whole process of uploading would be like this below. Below is the full client side JavaScript code. 1: <script type="text/javascript" src="~/Scripts/async.js"></script> 2: <script type="text/javascript"> 3: $(function () { 4: $("#upload_button_blob").click(function () { 5: // assert the browser support html5 6: if (window.File && window.Blob && window.FormData) { 7: alert("Your brwoser is awesome, let's rock!"); 8: } 9: else { 10: alert("Oh man plz update to a modern browser before try is cool stuff out."); 11: return; 12: } 13:  14: // start to upload each files in chunks 15: var files = $("#upload_files")[0].files; 16: for (var i = 0; i < files.length; i++) { 17: var file = files[i]; 18: var fileSize = file.size; 19: var fileName = file.name; 20:  21: // calculate the start and end byte index for each blocks(chunks) 22: // with the index, file name and index list for future using 23: var blockSizeInKB = $("#block_size").val(); 24: var blockSize = blockSizeInKB * 1024; 25: var blocks = []; 26: var offset = 0; 27: var index = 0; 28: var list = ""; 29: while (offset < fileSize) { 30: var start = offset; 31: var end = Math.min(offset + blockSize, fileSize); 32:  33: blocks.push({ 34: name: fileName, 35: index: index, 36: start: start, 37: end: end 38: }); 39: list += index + ","; 40:  41: offset = end; 42: index++; 43: } 44:  45: // define the function array and push all chunk upload operation into this array 46: var putBlocks = []; 47: blocks.forEach(function (block) { 48: putBlocks.push(function (callback) { 49: // load blob based on the start and end index for each chunks 50: var blob = file.slice(block.start, block.end); 51: // put the file name, index and blob into a temporary from 52: var fd = new FormData(); 53: fd.append("name", block.name); 54: fd.append("index", block.index); 55: fd.append("file", blob); 56: // post the form to backend service (asp.net mvc controller action) 57: $.ajax({ 58: url: "/Home/UploadInFormData", 59: data: fd, 60: processData: false, 61: contentType: "multipart/form-data", 62: type: "POST", 63: success: function (result) { 64: if (!result.success) { 65: alert(result.error); 66: } 67: callback(null, block.index); 68: } 69: }); 70: }); 71: }); 72:  73: // invoke the functions one by one 74: // then invoke the commit ajax call to put blocks into blob in azure storage 75: async.series(putBlocks, function (error, result) { 76: var data = { 77: name: fileName, 78: list: list 79: }; 80: $.post("/Home/Commit", data, function (result) { 81: if (!result.success) { 82: alert(result.error); 83: } 84: else { 85: alert("done!"); 86: } 87: }); 88: }); 89: } 90: }); 91: }); 92: </script> And below is the full ASP.NET MVC controller code. 1: public class HomeController : Controller 2: { 3: private CloudStorageAccount _account; 4: private CloudBlobClient _client; 5:  6: public HomeController() 7: : base() 8: { 9: _account = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("DataConnectionString")); 10: _client = _account.CreateCloudBlobClient(); 11: } 12:  13: public ActionResult Index() 14: { 15: ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application."; 16:  17: return View(); 18: } 19:  20: [HttpPost] 21: public JsonResult UploadInFormData() 22: { 23: var error = string.Empty; 24: try 25: { 26: var name = Request.Form["name"]; 27: var index = int.Parse(Request.Form["index"]); 28: var file = Request.Files[0]; 29: var id = Convert.ToBase64String(BitConverter.GetBytes(index)); 30:  31: var container = _client.GetContainerReference("test"); 32: container.CreateIfNotExists(); 33: var blob = container.GetBlockBlobReference(name); 34: blob.PutBlock(id, file.InputStream, null); 35: } 36: catch (Exception e) 37: { 38: error = e.ToString(); 39: } 40:  41: return new JsonResult() 42: { 43: Data = new 44: { 45: success = string.IsNullOrWhiteSpace(error), 46: error = error 47: } 48: }; 49: } 50:  51: [HttpPost] 52: public JsonResult Commit() 53: { 54: var error = string.Empty; 55: try 56: { 57: var name = Request.Form["name"]; 58: var list = Request.Form["list"]; 59: var ids = list 60: .Split(',') 61: .Where(id => !string.IsNullOrWhiteSpace(id)) 62: .Select(id => Convert.ToBase64String(BitConverter.GetBytes(int.Parse(id)))) 63: .ToArray(); 64:  65: var container = _client.GetContainerReference("test"); 66: container.CreateIfNotExists(); 67: var blob = container.GetBlockBlobReference(name); 68: blob.PutBlockList(ids); 69: } 70: catch (Exception e) 71: { 72: error = e.ToString(); 73: } 74:  75: return new JsonResult() 76: { 77: Data = new 78: { 79: success = string.IsNullOrWhiteSpace(error), 80: error = error 81: } 82: }; 83: } 84: } And if we selected a file from the browser we will see our application will upload chunks in the size we specified to the server through ajax call in background, and then commit all chunks in one blob. Then we can find the blob in our Windows Azure Blob Storage.   Optimized by Parallel Upload In previous example we just uploaded our file in chunks. This solved the problem that ASP.NET MVC request content size limitation as well as the Windows Azure load balancer timeout. But it might introduce the performance problem since we uploaded chunks in sequence. In order to improve the upload performance we could modify our client side code a bit to make the upload operation invoked in parallel. The good news is that, “async.js” library provides the parallel execution function. If you remembered the code we invoke the service to upload chunks, it utilized “async.series” which means all functions will be executed in sequence. Now we will change this code to “async.parallel”. This will invoke all functions in parallel. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.parallel(putBlocks, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: }); In this way all chunks will be uploaded to the server side at the same time to maximize the bandwidth usage. This should work if the file was not very large and the chunk size was not very small. But for large file this might introduce another problem that too many ajax calls are sent to the server at the same time. So the best solution should be, upload the chunks in parallel with maximum concurrency limitation. The code below specified the concurrency limitation to 4, which means at the most only 4 ajax calls could be invoked at the same time. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.parallelLimit(putBlocks, 4, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: });   Summary In this post we discussed how to upload files in chunks to the backend service and then upload them into Windows Azure Blob Storage in blocks. We focused on the frontend side and leverage three new feature introduced in HTML 5 which are - File.slice: Read part of the file by specifying the start and end byte index. - Blob: File-like interface which contains the part of the file content. - FormData: Temporary form element that we can pass the chunk alone with some metadata to the backend service. Then we discussed the performance consideration of chunk uploading. Sequence upload cannot provide maximized upload speed, but the unlimited parallel upload might crash the browser and server if too many chunks. So we finally came up with the solution to upload chunks in parallel with the concurrency limitation. We also demonstrated how to utilize “async.js” JavaScript library to help us control the asynchronize call and the parallel limitation.   Regarding the chunk size and the parallel limitation value there is no “best” value. You need to test vary composition and find out the best one for your particular scenario. It depends on the local bandwidth, client machine cores and the server side (Windows Azure Cloud Service Virtual Machine) cores, memory and bandwidth. Below is one of my performance test result. The client machine was Windows 8 IE 10 with 4 cores. I was using Microsoft Cooperation Network. The web site was hosted on Windows Azure China North data center (in Beijing) with one small web role (1.7GB 1 core CPU, 1.75GB memory with 100Mbps bandwidth). The test cases were - Chunk size: 512KB, 1MB, 2MB, 4MB. - Upload Mode: Sequence, parallel (unlimited), parallel with limit (4 threads, 8 threads). - Chunk Format: base64 string, binaries. - Target file: 100MB. - Each case was tested 3 times. Below is the test result chart. Some thoughts, but not guidance or best practice: - Parallel gets better performance than series. - No significant performance improvement between parallel 4 threads and 8 threads. - Transform with binaries provides better performance than base64. - In all cases, chunk size in 1MB - 2MB gets better performance.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Introducing… SharePress!

    - by Bil Simser
    For those that follow me I’ve been away from blogging and twittering for a couple of months. This is the reason. For the last few months I’ve been working with a cross-functional team putting together a new product from the people that run WordPress, the free premiere blogging platform. The result is a new product we call SharePress, a highly extensible blogging and content management platform with the usability of WordPress and the power of SharePoint combined into a single product. SharePress gives you SharePoint sites that are SEO-friendly delivered with a Web 2.0 ease of use, leveraging all of the existing abilities of SharePoint and WordPress that we know today. The Reason Back in December I was approached by the WordPress team about building a new platform that took advantage of the power of SharePoint but the ease of WordPress. I’m no stranger to WordPress and it’s 5 minute no-holds-barred install (I’ve always wanted SharePoint to do this!) and I run my personal blog on WordPress as does my better half, Princess Jenn. There’s always been a pitch by so-called Web 2.0 applications to deliver the power of SharePoint but the ease of [insert product here] over the past year or so. I checked each and every one of them out, but they fell woefully short when it came to SharePoint’s document management, versioning, and customization. They try, but it’s never been up to par in my books. On the flipside, SharePoint has always been tops in collaboration in the Enterprise but it’s painful to develop web parts, UI customization can be tricky, and there’s just no user community for something as simple as themes and designs. The Product Enter SharePress. Is it SharePoint? Is it WordPress? It’s both, and neither. Everything you like about both products are there but this is a bold new product that is positioned to bring SharePoint to the masses while maintaining the fidelity of an Enterprise 2.0 collaboration platform. SharePress delivers on all fronts including: The ability to leverage any WordPress/Joomla/Drupal/DotNetNuke themes and skins inside of SharePoint Run any WordPress/Drupal/Joomla/DotNetNuke/SharePoint plug-in/module/web part/feature works out of the box with SharePress SEO-friendly URLs and pages Permalinks for all content All the features of SharePoint Server 2010 (including InfoPath, Excel, and Access services) included in the price Small deployment footprint. You decide how much to deploy and where. Independent Database Abstraction Layer (iDal) that allows you to deploy to SQL Server 2005/2008, MySQL, and PostgreSQL Portable Rendering Engine Layer (PREL) so you host .NET or PHP on Apache or IIS (version 7 or higher). The install feature is built around WordPress and it’s famous 5-minute install (actually, it’s never taken me more than 1 minute). SharePress installs with two screens after the files are uploaded to your server (which can be done entirely using FTP): After you enter two fields of information click “Install SharePress” and you’ll be done: No mess, no fuss, no complicated dependencies, and no server access required! How simpler could this be? The Technology WordPress plug-ins and themes working with SharePoint? Of course! The answer is IronPython which has now reached a maturity level capable of doing on the fly code language conversions. SharePress is a brand new product not built on top of any previous platform but leverages all the power of each of those applications through a patent pending technique called SharePress Multi-plAtfoRm Technology (SMART). SMART will convert PHP code on the fly into Python (using SWIG as an intermediate processor) which is then compiled to MSIL and then delivered back as an ASP.NET MVC application (output is C# or VB.NET, but you can build your own SMART converter to output a different language). Sound complicated? It is, but it’s all behind the scenes and you don’t have to worry about a thing. This image illustrates the technology stack and process: So users can load up out of the box PHP themes and plug-ins from the WordPress/Joomla/Drupal community into the SMART converter and output MSIL that is used by the SharePress engine and rendered on the fly to the end user. Supported PHP versions are 4.xx and 5.xx with version 6 support to come when it’s released. Similarly you can take any .NET application, DotNetNuke Module, SharePoint Web Part or event handler and feed it into the converter to output the same. Everything is reverse compiled into MSIL so it becomes technology agnostic. No source code access is needed and the SMART converter can handle obfuscated .NET assemblies that were built with .NET 1.0, 1.1, 2.0, 3.5, and 4.0. With this technology you can also with the flip of a switch have the output create PHP pages for you. This allows you to run SharePress on Unix based systems running PHP and MySQL, allowing you to deliver your SharePoint like experience to your users with a $0 infrastructure footprint. Here’s SharePress with the default WordPress post imported then a stock SharePoint collaboration site was imported. The site was then applied with the default Kubrick theme from WordPress. The Features Deploy any of the freely available 100,000 WordPress/Joomla/Drupal themes instantly to your runtime SharePress environment and preview or activate them right from your browser. Built-in Web 2.0 jQuery Enabled End User and Administrator Web Interface. Never have to remote into a server again! Run any SharePoint Web Part or Event Handler directly without modification or access to source code in SharePress. Use any WordPress/Joomla/Drupal plug-in directly in SharePress, no local admin or access to server. Just upload and activate. Upload and Activate any SharePoint Solution Package to any site remotely. No rebuilding. Changes made to sites require no compiling or rebuilding and are published immediately. Password Protected Content. You can give passwords to individual posts, articles, pages, documents, forms, and list items. A powerful polymorphic Captcha system backs the security interface and vendors can easily tie into smart card readers, fingerprint readers, and retina scanners for authorization and identification. OpenID, Windows Live, and Windows Authentication are supported out of the box. Infinitely customizable and extensible. You can leverage plug-ins from the open source community to do practically anything, all configured and uploaded via the browser. Additionally the developer API (available soon) allows you to build extensions in .NET, PHP, and Python with little effort. Easy Importing. We have importers for Blogger, WordPress, Drupal, Joomla, DotNetNuke, and SharePoint so you can populate your site quickly and easily with full metadata modeling and creation. Banner Management. It’s easy to setup banners for your web site complete with impression numbers, special URLs, and more. Menu Manager. The Menu Manager allows you to create as many menus as you want, each one can be associated to specific audiences or roles and then be styled across multiple contexts including the same menu delivered as a fly out, rollover, drop down, and just about any navigation you can think of. Collaborative ShareBook. Our exclusive book feature allows you to setup a “book” and then authorize individuals to contribute content. Permalinks. All content in SharePress has a permanent or “perma link” associated with it so people can link to it freely without fear of broken links. Apache or IIS, Unix / Linux / BSD / Solaris / Windows / Mac OS X support. Deliver SharePress the way *you* want from the platform *you* decide. Database Independence. We know people wanted to run on any database platform so SharePress is built on top of a database abstraction layer that allows you to run on SQL Server, MySQL, PostgreSQL. Other databases can be supported by writing a supporting database script consisting of fourteen function calls. The script can be written in Perl, Python, AWK, PowerShell, Unix Shell scripts, VBA, or simple DOS batch files. The Team SharePress is the work of a lot of people in both the WordPress and SharePoint community. I worked with a lot of SharePoint MVPs to create this new product as we really wanted to deliver the most compatible and feature rich system in a product that we would be proud of. Many thanks go out to Eli Bleeker, Todd Robillard, Scot Larson, Daniel Hillier, Shane Fox, Box Peran, Amanda English, and Bill Murray for doing the heavy lifting and all of their expertise and innovative thinking to get this product out. Licensing and Pricing SharePress is still in the final stages for pricing but we’re looking at a price point somewhere between $99-$100 to make it affordable for everyone. We plan to announce final pricing sometime in the next few weeks. There are no additional charges for Enterprise versions or additional features. Everything you see is what’s available and it’s just a matter of lighting up your site with whatever feature you want to enable. The product will not be open source but source code licenses will be available to ISVs who are interested in interfacing with the API at a low level. Cost will be $25,000 USD per developer and gives you complete access to the source code to the SharePress Foundation System and the .NET 4.0 Framework source code. Conclusion We hope you enjoy the launch of SharePress as the new premium blogging and content management platform for both Intranets and the Internet. We think we’ve build the best of breed solutions here and made it easy for anyone to get started with a minimal of infrastructure but allow the scalability of SharePress to shine through in the Enterprise 2.0 world. We encourage your feedback so please leave comments as to what you’re looking for in this system as we’re always evolving it to make it a better product for everyone.

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  • Building a Windows Phone 7 Twitter Application using Silverlight

    - by ScottGu
    On Monday I had the opportunity to present the MIX 2010 Day 1 Keynote in Las Vegas (you can watch a video of it here).  In the keynote I announced the release of the Silverlight 4 Release Candidate (we’ll ship the final release of it next month) and the VS 2010 RC tools for Silverlight 4.  I also had the chance to talk for the first time about how Silverlight and XNA can now be used to build Windows Phone 7 applications. During my talk I did two quick Windows Phone 7 coding demos using Silverlight – a quick “Hello World” application and a “Twitter” data-snacking application.  Both applications were easy to build and only took a few minutes to create on stage.  Below are the steps you can follow yourself to build them on your own machines as well. [Note: In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Building a “Hello World” Windows Phone 7 Application First make sure you’ve installed the Windows Phone Developer Tools CTP – this includes the Visual Studio 2010 Express for Windows Phone development tool (which will be free forever and is the only thing you need to develop and build Windows Phone 7 applications) as well as an add-on to the VS 2010 RC that enables phone development within the full VS 2010 as well. After you’ve downloaded and installed the Windows Phone Developer Tools CTP, launch the Visual Studio 2010 Express for Windows Phone that it installs or launch the VS 2010 RC (if you have it already installed), and then choose “File”->”New Project.”  Here, you’ll find the usual list of project template types along with a new category: “Silverlight for Windows Phone”. The first CTP offers two application project templates. The first is the “Windows Phone Application” template - this is what we’ll use for this example. The second is the “Windows Phone List Application” template - which provides the basic layout for a master-details phone application: After creating a new project, you’ll get a view of the design surface and markup. Notice that the design surface shows the phone UI, letting you easily see how your application will look while you develop. For those familiar with Visual Studio, you’ll also find the familiar ToolBox, Solution Explorer and Properties pane. For our HelloWorld application, we’ll start out by adding a TextBox and a Button from the Toolbox. Notice that you get the same design experience as you do for Silverlight on the web or desktop. You can easily resize, position and align your controls on the design surface. Changing properties is easy with the Properties pane. We’ll change the name of the TextBox that we added to username and change the page title text to “Hello world.” We’ll then write some code by double-clicking on the button and create an event handler in the code-behind file (MainPage.xaml.cs). We’ll start out by changing the title text of the application. The project template included this title as a TextBlock with the name textBlockListTitle (note that the current name incorrectly includes the word “list”; that will be fixed for the final release.)  As we write code against it we get intellisense showing the members available.  Below we’ll set the Text property of the title TextBlock to “Hello “ + the Text property of the TextBox username: We now have all the code necessary for a Hello World application.  We have two choices when it comes to deploying and running the application. We can either deploy to an actual device itself or use the built-in phone emulator: Because the phone emulator is actually the phone operating system running in a virtual machine, we’ll get the same experience developing in the emulator as on the device. For this sample, we’ll just press F5 to start the application with debugging using the emulator.  Once the phone operating system loads, the emulator will run the new “Hello world” application exactly as it would on the device: Notice that we can change several settings of the emulator experience with the emulator toolbar – which is a floating toolbar on the top right.  This includes the ability to re-size/zoom the emulator and two rotate buttons.  Zoom lets us zoom into even the smallest detail of the application: The orientation buttons allow us easily see what the application looks like in landscape mode (orientation change support is just built into the default template): Note that the emulator can be reused across F5 debug sessions - that means that we don’t have to start the emulator for every deployment. We’ve added a dialog that will help you from accidentally shutting down the emulator if you want to reuse it.  Launching an application on an already running emulator should only take ~3 seconds to deploy and run. Within our Hello World application we’ll click the “username” textbox to give it focus.  This will cause the software input panel (SIP) to open up automatically.  We can either type a message or – since we are using the emulator – just type in text.  Note that the emulator works with Windows 7 multi-touch so, if you have a touchscreen, you can see how interaction will feel on a device just by pressing the screen. We’ll enter “MIX 10” in the textbox and then click the button – this will cause the title to update to be “Hello MIX 10”: We provide the same Visual Studio experience when developing for the phone as other .NET applications. This means that we can set a breakpoint within the button event handler, press the button again and have it break within the debugger: Building a “Twitter” Windows Phone 7 Application using Silverlight Rather than just stop with “Hello World” let’s keep going and evolve it to be a basic Twitter client application. We’ll return to the design surface and add a ListBox, using the snaplines within the designer to fit it to the device screen and make the best use of phone screen real estate.  We’ll also rename the Button “Lookup”: We’ll then return to the Button event handler in Main.xaml.cs, and remove the original “Hello World” line of code and take advantage of the WebClient networking class to asynchronously download a Twitter feed. This takes three lines of code in total: (1) declaring and creating the WebClient, (2) attaching an event handler and then (3) calling the asynchronous DownloadStringAsync method. In the DownloadStringAsync call, we’ll pass a Twitter Uri plus a query string which pulls the text from the “username” TextBox. This feed will pull down the respective user’s most frequent posts in an XML format. When the call completes, the DownloadStringCompleted event is fired and our generated event handler twitter_DownloadStringCompleted will be called: The result returned from the Twitter call will come back in an XML based format.  To parse this we’ll use LINQ to XML. LINQ to XML lets us create simple queries for accessing data in an xml feed. To use this library, we’ll first need to add a reference to the assembly (right click on the References folder in the solution explorer and choose “Add Reference): We’ll then add a “using System.Xml.Linq” namespace reference at the top of the code-behind file at the top of Main.xaml.cs file: We’ll then add a simple helper class called TwitterItem to our project. TwitterItem has three string members – UserName, Message and ImageSource: We’ll then implement the twitter_DownloadStringCompleted event handler and use LINQ to XML to parse the returned XML string from Twitter.  What the query is doing is pulling out the three key pieces of information for each Twitter post from the username we passed as the query string. These are the ImageSource for their profile image, the Message of their tweet and their UserName. For each Tweet in the XML, we are creating a new TwitterItem in the IEnumerable<XElement> returned by the Linq query.  We then assign the generated TwitterItem sequence to the ListBox’s ItemsSource property: We’ll then do one more step to complete the application. In the Main.xaml file, we’ll add an ItemTemplate to the ListBox. For the demo, I used a simple template that uses databinding to show the user’s profile image, their tweet and their username. <ListBox Height="521" HorizonalAlignment="Left" Margin="0,131,0,0" Name="listBox1" VerticalAlignment="Top" Width="476"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal" Height="132"> <Image Source="{Binding ImageSource}" Height="73" Width="73" VerticalAlignment="Top" Margin="0,10,8,0"/> <StackPanel Width="370"> <TextBlock Text="{Binding UserName}" Foreground="#FFC8AB14" FontSize="28" /> <TextBlock Text="{Binding Message}" TextWrapping="Wrap" FontSize="24" /> </StackPanel> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Now, pressing F5 again, we are able to reuse the emulator and re-run the application. Once the application has launched, we can type in a Twitter username and press the  Button to see the results. Try my Twitter user name (scottgu) and you’ll get back a result of TwitterItems in the Listbox: Try using the mouse (or if you have a touchscreen device your finger) to scroll the items in the Listbox – you should find that they move very fast within the emulator.  This is because the emulator is hardware accelerated – and so gives you the same fast performance that you get on the actual phone hardware. Summary Silverlight and the VS 2010 Tools for Windows Phone (and the corresponding Expression Blend Tools for Windows Phone) make building Windows Phone applications both really easy and fun.  At MIX this week a number of great partners (including Netflix, FourSquare, Seesmic, Shazaam, Major League Soccer, Graphic.ly, Associated Press, Jackson Fish and more) showed off some killer application prototypes they’ve built over the last few weeks.  You can watch my full day 1 keynote to see them in action. I think they start to show some of the promise and potential of using Silverlight with Windows Phone 7.  I’ll be doing more blog posts in the weeks and months ahead that cover that more. Hope this helps, Scott

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  • Time Warp

    - by Jesse
    It’s no secret that daylight savings time can wreak havoc on systems that rely heavily on dates. The system I work on is centered around recording dates and times, so naturally my co-workers and I have seen our fair share of date-related bugs. From time to time, however, we come across something that we haven’t seen before. A few weeks ago the following error message started showing up in our logs: “The supplied DateTime represents an invalid time. For example, when the clock is adjusted forward, any time in the period that is skipped is invalid.” This seemed very cryptic, especially since it was coming from areas of our application that are typically only concerned with capturing date-only (no explicit time component) from the user, like reports that take a “start date” and “end date” parameter. For these types of parameters we just leave off the time component when capturing the date values, so midnight is used as a “placeholder” time. How is midnight an “invalid time”? Globalization Is Hard Over the last couple of years our software has been rolled out to users in several countries outside of the United States, including Brazil. Brazil begins and ends daylight savings time at midnight on pre-determined days of the year. On October 16, 2011 at midnight many areas in Brazil began observing daylight savings time at which time their clocks were set forward one hour. This means that at the instant it became midnight on October 16, it actually became 1:00 AM, so any time between 12:00 AM and 12:59:59 AM never actually happened. Because we store all date values in the database in UTC, always adjust any “local” dates provided by a user to UTC before using them as filters in a query. The error we saw was thrown by .NET when trying to convert the Brazilian local time of 2011-10-16 12:00 AM to UTC since that local time never actually existed. We hadn’t experienced this same issue with any of our US customers because the daylight savings time changes in the US occur at 2:00 AM which doesn’t conflict with our “placeholder” time of midnight. Detecting Invalid Times In .NET you might use code similar to the following for converting a local time to UTC: var localDate = new DateTime(2011, 10, 16); //2011-10-16 @ midnight const string timeZoneId = "E. South America Standard Time"; //Windows system timezone Id for "Brasilia" timezone. var localTimeZone = TimeZoneInfo.FindSystemTimeZoneById(timeZoneId); var convertedDate = TimeZoneInfo.ConvertTimeToUtc(localDate, localTimeZone); The code above throws the “invalid time” exception referenced above. We could try to detect whether or not the local time is invalid with something like this: var localDate = new DateTime(2011, 10, 16); //2011-10-16 @ midnight const string timeZoneId = "E. South America Standard Time"; //Windows system timezone Id for "Brasilia" timezone. var localTimeZone = TimeZoneInfo.FindSystemTimeZoneById(timeZoneId); if (localTimeZone.IsInvalidTime(localDate)) localDate = localDate.AddHours(1); var convertedDate = TimeZoneInfo.ConvertTimeToUtc(localDate, localTimeZone); This code works in this particular scenario, but it hardly seems robust. It also does nothing to address the issue that can arise when dealing with the ambiguous times that fall around the end of daylight savings. When we roll the clocks back an hour they record the same hour on the same day twice in a row. To continue on with our Brazil example, on February 19, 2012 at 12:00 AM, it will immediately become February 18, 2012 at 11:00 PM all over again. In this scenario, how should we interpret February 18, 2011 11:30 PM? Enter Noda Time I heard about Noda Time, the .NET port of the Java library Joda Time, a little while back and filed it away in the back of my mind under the “sounds-like-it-might-be-useful-someday” category.  Let’s see how we might deal with the issue of invalid and ambiguous local times using Noda Time (note that as of this writing the samples below will only work using the latest code available from the Noda Time repo on Google Code. The NuGet package version 0.1.0 published 2011-08-19 will incorrectly report unambiguous times as being ambiguous) : var localDateTime = new LocalDateTime(2011, 10, 16, 0, 0); const string timeZoneId = "Brazil/East"; var timezone = DateTimeZone.ForId(timeZoneId); var localDateTimeMaping = timezone.MapLocalDateTime(localDateTime); ZonedDateTime unambiguousLocalDateTime; switch (localDateTimeMaping.Type) { case ZoneLocalMapping.ResultType.Unambiguous: unambiguousLocalDateTime = localDateTimeMaping.UnambiguousMapping; break; case ZoneLocalMapping.ResultType.Ambiguous: unambiguousLocalDateTime = localDateTimeMaping.EarlierMapping; break; case ZoneLocalMapping.ResultType.Skipped: unambiguousLocalDateTime = new ZonedDateTime( localDateTimeMaping.ZoneIntervalAfterTransition.Start, timezone); break; default: throw new InvalidOperationException(string.Format("Unexpected mapping result type: {0}", localDateTimeMaping.Type)); } var convertedDateTime = unambiguousLocalDateTime.ToInstant().ToDateTimeUtc(); Let’s break this sample down: I’m using the Noda Time ‘LocalDateTime’ object to represent the local date and time. I’ve provided the year, month, day, hour, and minute (zeros for the hour and minute here represent midnight). You can think of a ‘LocalDateTime’ as an “invalidated” date and time; there is no information available about the time zone that this date and time belong to, so Noda Time can’t make any guarantees about its ambiguity. The ‘timeZoneId’ in this sample is different than the ones above. In order to use the .NET TimeZoneInfo class we need to provide Windows time zone ids. Noda Time expects an Olson (tz / zoneinfo) time zone identifier and does not currently offer any means of mapping the Windows time zones to their Olson counterparts, though project owner Jon Skeet has said that some sort of mapping will be publicly accessible at some point in the future. I’m making use of the Noda Time ‘DateTimeZone.MapLocalDateTime’ method to disambiguate the original local date time value. This method returns an instance of the Noda Time object ‘ZoneLocalMapping’ containing information about the provided local date time maps to the provided time zone.  The disambiguated local date and time value will be stored in the ‘unambiguousLocalDateTime’ variable as an instance of the Noda Time ‘ZonedDateTime’ object. An instance of this object represents a completely unambiguous point in time and is comprised of a local date and time, a time zone, and an offset from UTC. Instances of ZonedDateTime can only be created from within the Noda Time assembly (the constructor is ‘internal’) to ensure to callers that each instance represents an unambiguous point in time. The value of the ‘unambiguousLocalDateTime’ might vary depending upon the ‘ResultType’ returned by the ‘MapLocalDateTime’ method. There are three possible outcomes: If the provided local date time is unambiguous in the provided time zone I can immediately set the ‘unambiguousLocalDateTime’ variable from the ‘Unambiguous Mapping’ property of the mapping returned by the ‘MapLocalDateTime’ method. If the provided local date time is ambiguous in the provided time zone (i.e. it falls in an hour that was repeated when moving clocks backward from Daylight Savings to Standard Time), I can use the ‘EarlierMapping’ property to get the earlier of the two possible local dates to define the unambiguous local date and time that I need. I could have also opted to use the ‘LaterMapping’ property in this case, or even returned an error and asked the user to specify the proper choice. The important thing to note here is that as the programmer I’ve been forced to deal with what appears to be an ambiguous date and time. If the provided local date time represents a skipped time (i.e. it falls in an hour that was skipped when moving clocks forward from Standard Time to Daylight Savings Time),  I have access to the time intervals that fell immediately before and immediately after the point in time that caused my date to be skipped. In this case I have opted to disambiguate my local date and time by moving it forward to the beginning of the interval immediately following the skipped period. Again, I could opt to use the end of the interval immediately preceding the skipped period, or raise an error depending on the needs of the application. The point of this code is to convert a local date and time to a UTC date and time for use in a SQL Server database, so the final ‘convertedDate’  variable (typed as a plain old .NET DateTime) has its value set from a Noda Time ‘Instant’. An 'Instant’ represents a number of ticks since 1970-01-01 at midnight (Unix epoch) and can easily be converted to a .NET DateTime in the UTC time zone using the ‘ToDateTimeUtc()’ method. This sample is admittedly contrived and could certainly use some refactoring, but I think it captures the general approach needed to take a local date and time and convert it to UTC with Noda Time. At first glance it might seem that Noda Time makes this “simple” code more complicated and verbose because it forces you to explicitly deal with the local date disambiguation, but I feel that the length and complexity of the Noda Time sample is proportionate to the complexity of the problem. Using TimeZoneInfo leaves you susceptible to overlooking ambiguous and skipped times that could result in run-time errors or (even worse) run-time data corruption in the form of a local date and time being adjusted to UTC incorrectly. I should point out that this research is my first look at Noda Time and I know that I’ve only scratched the surface of its full capabilities. I also think it’s safe to say that it’s still beta software for the time being so I’m not rushing out to use it production systems just yet, but I will definitely be tinkering with it more and keeping an eye on it as it progresses.

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  • C#: String Concatenation vs Format vs StringBuilder

    - by James Michael Hare
    I was looking through my groups’ C# coding standards the other day and there were a couple of legacy items in there that caught my eye.  They had been passed down from committee to committee so many times that no one even thought to second guess and try them for a long time.  It’s yet another example of how micro-optimizations can often get the best of us and cause us to write code that is not as maintainable as it could be for the sake of squeezing an extra ounce of performance out of our software. So the two standards in question were these, in paraphrase: Prefer StringBuilder or string.Format() to string concatenation. Prefer string.Equals() with case-insensitive option to string.ToUpper().Equals(). Now some of you may already know what my results are going to show, as these items have been compared before on many blogs, but I think it’s always worth repeating and trying these yourself.  So let’s dig in. The first test was a pretty standard one.  When concattenating strings, what is the best choice: StringBuilder, string concattenation, or string.Format()? So before we being I read in a number of iterations from the console and a length of each string to generate.  Then I generate that many random strings of the given length and an array to hold the results.  Why am I so keen to keep the results?  Because I want to be able to snapshot the memory and don’t want garbage collection to collect the strings, hence the array to keep hold of them.  I also didn’t want the random strings to be part of the allocation, so I pre-allocate them and the array up front before the snapshot.  So in the code snippets below: num – Number of iterations. strings – Array of randomly generated strings. results – Array to hold the results of the concatenation tests. timer – A System.Diagnostics.Stopwatch() instance to time code execution. start – Beginning memory size. stop – Ending memory size. after – Memory size after final GC. So first, let’s look at the concatenation loop: 1: // build num strings using concattenation. 2: for (int i = 0; i < num; i++) 3: { 4: results[i] = "This is test #" + i + " with a result of " + strings[i]; 5: } Pretty standard, right?  Next for string.Format(): 1: // build strings using string.Format() 2: for (int i = 0; i < num; i++) 3: { 4: results[i] = string.Format("This is test #{0} with a result of {1}", i, strings[i]); 5: }   Finally, StringBuilder: 1: // build strings using StringBuilder 2: for (int i = 0; i < num; i++) 3: { 4: var builder = new StringBuilder(); 5: builder.Append("This is test #"); 6: builder.Append(i); 7: builder.Append(" with a result of "); 8: builder.Append(strings[i]); 9: results[i] = builder.ToString(); 10: } So I take each of these loops, and time them by using a block like this: 1: // get the total amount of memory used, true tells it to run GC first. 2: start = System.GC.GetTotalMemory(true); 3:  4: // restart the timer 5: timer.Reset(); 6: timer.Start(); 7:  8: // *** code to time and measure goes here. *** 9:  10: // get the current amount of memory, stop the timer, then get memory after GC. 11: stop = System.GC.GetTotalMemory(false); 12: timer.Stop(); 13: other = System.GC.GetTotalMemory(true); So let’s look at what happens when I run each of these blocks through the timer and memory check at 500,000 iterations: 1: Operator + - Time: 547, Memory: 56104540/55595960 - 500000 2: string.Format() - Time: 749, Memory: 57295812/55595960 - 500000 3: StringBuilder - Time: 608, Memory: 55312888/55595960 – 500000   Egad!  string.Format brings up the rear and + triumphs, well, at least in terms of speed.  The concat burns more memory than StringBuilder but less than string.Format().  This shows two main things: StringBuilder is not always the panacea many think it is. The difference between any of the three is miniscule! The second point is extremely important!  You will often here people who will grasp at results and say, “look, operator + is 10% faster than StringBuilder so always use StringBuilder.”  Statements like this are a disservice and often misleading.  For example, if I had a good guess at what the size of the string would be, I could have preallocated my StringBuffer like so:   1: for (int i = 0; i < num; i++) 2: { 3: // pre-declare StringBuilder to have 100 char buffer. 4: var builder = new StringBuilder(100); 5: builder.Append("This is test #"); 6: builder.Append(i); 7: builder.Append(" with a result of "); 8: builder.Append(strings[i]); 9: results[i] = builder.ToString(); 10: }   Now let’s look at the times: 1: Operator + - Time: 551, Memory: 56104412/55595960 - 500000 2: string.Format() - Time: 753, Memory: 57296484/55595960 - 500000 3: StringBuilder - Time: 525, Memory: 59779156/55595960 - 500000   Whoa!  All of the sudden StringBuilder is back on top again!  But notice, it takes more memory now.  This makes perfect sense if you examine the IL behind the scenes.  Whenever you do a string concat (+) in your code, it examines the lengths of the arguments and creates a StringBuilder behind the scenes of the appropriate size for you. But even IF we know the approximate size of our StringBuilder, look how much less readable it is!  That’s why I feel you should always take into account both readability and performance.  After all, consider all these timings are over 500,000 iterations.   That’s at best  0.0004 ms difference per call which is neglidgable at best.  The key is to pick the best tool for the job.  What do I mean?  Consider these awesome words of wisdom: Concatenate (+) is best at concatenating.  StringBuilder is best when you need to building. Format is best at formatting. Totally Earth-shattering, right!  But if you consider it carefully, it actually has a lot of beauty in it’s simplicity.  Remember, there is no magic bullet.  If one of these always beat the others we’d only have one and not three choices. The fact is, the concattenation operator (+) has been optimized for speed and looks the cleanest for joining together a known set of strings in the simplest manner possible. StringBuilder, on the other hand, excels when you need to build a string of inderterminant length.  Use it in those times when you are looping till you hit a stop condition and building a result and it won’t steer you wrong. String.Format seems to be the looser from the stats, but consider which of these is more readable.  Yes, ignore the fact that you could do this with ToString() on a DateTime.  1: // build a date via concatenation 2: var date1 = (month < 10 ? string.Empty : "0") + month + '/' 3: + (day < 10 ? string.Empty : "0") + '/' + year; 4:  5: // build a date via string builder 6: var builder = new StringBuilder(10); 7: if (month < 10) builder.Append('0'); 8: builder.Append(month); 9: builder.Append('/'); 10: if (day < 10) builder.Append('0'); 11: builder.Append(day); 12: builder.Append('/'); 13: builder.Append(year); 14: var date2 = builder.ToString(); 15:  16: // build a date via string.Format 17: var date3 = string.Format("{0:00}/{1:00}/{2:0000}", month, day, year); 18:  So the strength in string.Format is that it makes constructing a formatted string easy to read.  Yes, it’s slower, but look at how much more elegant it is to do zero-padding and anything else string.Format does. So my lesson is, don’t look for the silver bullet!  Choose the best tool.  Micro-optimization almost always bites you in the end because you’re sacrificing readability for performance, which is almost exactly the wrong choice 90% of the time. I love the rules of optimization.  They’ve been stated before in many forms, but here’s how I always remember them: For Beginners: Do not optimize. For Experts: Do not optimize yet. It’s so true.  Most of the time on today’s modern hardware, a micro-second optimization at the sake of readability will net you nothing because it won’t be your bottleneck.  Code for readability, choose the best tool for the job which will usually be the most readable and maintainable as well.  Then, and only then, if you need that extra performance boost after profiling your code and exhausting all other options… then you can start to think about optimizing.

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  • Metro: Namespaces and Modules

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can use the Windows JavaScript (WinJS) library to create namespaces. In particular, you learn how to use the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. You also learn how to hide private methods by using the module pattern. Why Do We Need Namespaces? Before we do anything else, we should start by answering the question: Why do we need namespaces? What function do they serve? Do they just add needless complexity to our Metro applications? After all, plenty of JavaScript libraries do just fine without introducing support for namespaces. For example, jQuery has no support for namespaces and jQuery is the most popular JavaScript library in the universe. If jQuery can do without namespaces, why do we need to worry about namespaces at all? Namespaces perform two functions in a programming language. First, namespaces prevent naming collisions. In other words, namespaces enable you to create more than one object with the same name without conflict. For example, imagine that two companies – company A and company B – both want to make a JavaScript shopping cart control and both companies want to name the control ShoppingCart. By creating a CompanyA namespace and CompanyB namespace, both companies can create a ShoppingCart control: a CompanyA.ShoppingCart and a CompanyB.ShoppingCart control. The second function of a namespace is organization. Namespaces are used to group related functionality even when the functionality is defined in different physical files. For example, I know that all of the methods in the WinJS library related to working with classes can be found in the WinJS.Class namespace. Namespaces make it easier to understand the functionality available in a library. If you are building a simple JavaScript application then you won’t have much reason to care about namespaces. If you need to use multiple libraries written by different people then namespaces become very important. Using WinJS.Namespace.define() In the WinJS library, the most basic method of creating a namespace is to use the WinJS.Namespace.define() method. This method enables you to declare a namespace (of arbitrary depth). The WinJS.Namespace.define() method has the following parameters: · name – A string representing the name of the new namespace. You can add nested namespace by using dot notation · members – An optional collection of objects to add to the new namespace For example, the following code sample declares two new namespaces named CompanyA and CompanyB.Controls. Both namespaces contain a ShoppingCart object which has a checkout() method: // Create CompanyA namespace with ShoppingCart WinJS.Namespace.define("CompanyA"); CompanyA.ShoppingCart = { checkout: function (){ return "Checking out from A"; } }; // Create CompanyB.Controls namespace with ShoppingCart WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); // Call CompanyA ShoppingCart checkout method console.log(CompanyA.ShoppingCart.checkout()); // Writes "Checking out from A" // Call CompanyB.Controls checkout method console.log(CompanyB.Controls.ShoppingCart.checkout()); // Writes "Checking out from B" In the code above, the CompanyA namespace is created by calling WinJS.Namespace.define(“CompanyA”). Next, the ShoppingCart is added to this namespace. The namespace is defined and an object is added to the namespace in separate lines of code. A different approach is taken in the case of the CompanyB.Controls namespace. The namespace is created and the ShoppingCart object is added to the namespace with the following single line of code: WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); Notice that CompanyB.Controls is a nested namespace. The top level namespace CompanyB contains the namespace Controls. You can declare a nested namespace using dot notation and the WinJS library handles the details of creating one namespace within the other. After the namespaces have been defined, you can use either of the two shopping cart controls. You call CompanyA.ShoppingCart.checkout() or you can call CompanyB.Controls.ShoppingCart.checkout(). Using WinJS.Namespace.defineWithParent() The WinJS.Namespace.defineWithParent() method is similar to the WinJS.Namespace.define() method. Both methods enable you to define a new namespace. The difference is that the defineWithParent() method enables you to add a new namespace to an existing namespace. The WinJS.Namespace.defineWithParent() method has the following parameters: · parentNamespace – An object which represents a parent namespace · name – A string representing the new namespace to add to the parent namespace · members – An optional collection of objects to add to the new namespace The following code sample demonstrates how you can create a root namespace named CompanyA and add a Controls child namespace to the CompanyA parent namespace: WinJS.Namespace.define("CompanyA"); WinJS.Namespace.defineWithParent(CompanyA, "Controls", { ShoppingCart: { checkout: function () { return "Checking out"; } } } ); console.log(CompanyA.Controls.ShoppingCart.checkout()); // Writes "Checking out" One significant advantage of using the defineWithParent() method over the define() method is the defineWithParent() method is strongly-typed. In other words, you use an object to represent the base namespace instead of a string. If you misspell the name of the object (CompnyA) then you get a runtime error. Using the Module Pattern When you are building a JavaScript library, you want to be able to create both public and private methods. Some methods, the public methods, are intended to be used by consumers of your JavaScript library. The public methods act as your library’s public API. Other methods, the private methods, are not intended for public consumption. Instead, these methods are internal methods required to get the library to function. You don’t want people calling these internal methods because you might need to change them in the future. JavaScript does not support access modifiers. You can’t mark an object or method as public or private. Anyone gets to call any method and anyone gets to interact with any object. The only mechanism for encapsulating (hiding) methods and objects in JavaScript is to take advantage of functions. In JavaScript, a function determines variable scope. A JavaScript variable either has global scope – it is available everywhere – or it has function scope – it is available only within a function. If you want to hide an object or method then you need to place it within a function. For example, the following code contains a function named doSomething() which contains a nested function named doSomethingElse(): function doSomething() { console.log("doSomething"); function doSomethingElse() { console.log("doSomethingElse"); } } doSomething(); // Writes "doSomething" doSomethingElse(); // Throws ReferenceError You can call doSomethingElse() only within the doSomething() function. The doSomethingElse() function is encapsulated in the doSomething() function. The WinJS library takes advantage of function encapsulation to hide all of its internal methods. All of the WinJS methods are defined within self-executing anonymous functions. Everything is hidden by default. Public methods are exposed by explicitly adding the public methods to namespaces defined in the global scope. Imagine, for example, that I want a small library of utility methods. I want to create a method for calculating sales tax and a method for calculating the expected ship date of a product. The following library encapsulates the implementation of my library in a self-executing anonymous function: (function (global) { // Public method which calculates tax function calculateTax(price) { return calculateFederalTax(price) + calculateStateTax(price); } // Private method for calculating state tax function calculateStateTax(price) { return price * 0.08; } // Private method for calculating federal tax function calculateFederalTax(price) { return price * 0.02; } // Public method which returns the expected ship date function calculateShipDate(currentDate) { currentDate.setDate(currentDate.getDate() + 4); return currentDate; } // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); })(this); // Show expected ship date var shipDate = CompanyA.Utilities.calculateShipDate(new Date()); console.log(shipDate); // Show price + tax var price = 12.33; var tax = CompanyA.Utilities.calculateTax(price); console.log(price + tax); In the code above, the self-executing anonymous function contains four functions: calculateTax(), calculateStateTax(), calculateFederalTax(), and calculateShipDate(). The following statement is used to expose only the calcuateTax() and the calculateShipDate() functions: // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); Because the calculateTax() and calcuateShipDate() functions are added to the CompanyA.Utilities namespace, you can call these two methods outside of the self-executing function. These are the public methods of your library which form the public API. The calculateStateTax() and calculateFederalTax() methods, on the other hand, are forever hidden within the black hole of the self-executing function. These methods are encapsulated and can never be called outside of scope of the self-executing function. These are the internal methods of your library. Summary The goal of this blog entry was to describe why and how you use namespaces with the WinJS library. You learned how to define namespaces using both the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. We also discussed how to hide private members and expose public members using the module pattern.

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  • Metro: Creating a Master/Detail View with a WinJS ListView Control

    - by Stephen.Walther
    The goal of this blog entry is to explain how you can create a simple master/detail view by using the WinJS ListView and Template controls. In particular, I explain how you can use a ListView control to display a list of movies and how you can use a Template control to display the details of the selected movie. Creating a master/detail view requires completing the following four steps: Create the data source – The data source contains the list of movies. Declare the ListView control – The ListView control displays the entire list of movies. It is the master part of the master/detail view. Declare the Details Template control – The Details Template control displays the details for the selected movie. It is the details part of the master/detail view. Handle the selectionchanged event – You handle the selectionchanged event to display the details for a movie when a new movie is selected. Creating the Data Source There is nothing special about our data source. We initialize a WinJS.Binding.List object to represent a list of movies: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })(); The data source is exposed to the rest of our application with the name ListViewDemos.movies. Declaring the ListView Control The ListView control is declared with the following markup: <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> The data-win-options attribute is used to set the following properties of the ListView control: itemDataSource – The ListView is bound to the list of movies which we created in the previous section. Notice that the ListView is bound to ListViewDemos.movies.dataSource and not just ListViewDemos.movies. itemTemplate – The item template contains the template used for rendering each item in the ListView. The markup for this template is included below. tabBehavior – This enumeration determines what happens when you tap or click on an item in the ListView. The possible values are directSelect, toggleSelect, invokeOnly, none. Because we want to handle the selectionchanged event, we set tapBehavior to the value directSelect. selectionMode – This enumeration determines whether you can select multiple items or only a single item. The possible values are none, single, multi. In the code above, this property is set to the value single. layout – You can use ListLayout or GridLayout with a ListView. If you want to display a vertical ListView, then you should select ListLayout. You must associate a ListView with an item template if you want to render anything interesting. The ListView above is associated with an item template named #masterItemTemplate. Here’s the markup for the masterItemTemplate: <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> This template simply renders the title of each movie. Declaring the Details Template Control The details part of the master/detail view is created with the help of a Template control. Here’s the markup used to declare the Details Template control: <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> The Details Template control displays the movie title and director.   Handling the selectionchanged Event The ListView control can raise two types of events: the iteminvoked and selectionchanged events. The iteminvoked event is raised when you click on a ListView item. The selectionchanged event is raised when one or more ListView items are selected. When you set the tapBehavior property of the ListView control to the value “directSelect” then tapping or clicking a list item raised both the iteminvoked and selectionchanged event. Tapping a list item causes the item to be selected and the item appears with a checkmark. In our code, we handle the selectionchanged event to update the movie details Template when you select a new movie. Here’s the code from the default.js file used to handle the selectionchanged event: var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); The code above sets up an event handler (listener) for the selectionchanged event. The event handler first verifies that an item has been selected in the ListView (selection.count() > 0). Next, the details for the movie are rendered using the movie details Template (we created this Template in the previous section). The Complete Code For the sake of completeness, I’ve included the complete code for the master/detail view below. I’ve included both the default.html, default.js, and movies.js files. Here is the final code for the default.html file: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewMasterDetail</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewMasterDetail references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/movies.js"></script> <style type="text/css"> body { font-size: xx-large; } .movie { padding: 5px; } #masterDetail { display: -ms-box; } #movieList { width: 300px; margin: 20px; } #movieDetails { margin: 20px; } </style> </head> <body> <!-- Templates --> <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> <!-- Master/Detail --> <div id="masterDetail"> <!-- Master --> <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> <!-- Detail --> <div id="movieDetails"></div> </div> </body> </html> Here is the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); } }; app.start(); })();   Here is the movies.js file: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })();   Summary The purpose of this blog entry was to describe how to create a simple master/detail view by taking advantage of the WinJS ListView control. We handled the selectionchanged event of the ListView control to display movie details when you select a movie in the ListView.

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  • Metro: Understanding Observables

    - by Stephen.Walther
    The goal of this blog entry is to describe how the Observer Pattern is implemented in the WinJS library. You learn how to create observable objects which trigger notifications automatically when their properties are changed. Observables enable you to keep your user interface and your application data in sync. For example, by taking advantage of observables, you can update your user interface automatically whenever the properties of a product change. Observables are the foundation of declarative binding in the WinJS library. The WinJS library is not the first JavaScript library to include support for observables. For example, both the KnockoutJS library and the Microsoft Ajax Library (now part of the Ajax Control Toolkit) support observables. Creating an Observable Imagine that I have created a product object like this: var product = { name: "Milk", description: "Something to drink", price: 12.33 }; Nothing very exciting about this product. It has three properties named name, description, and price. Now, imagine that I want to be notified automatically whenever any of these properties are changed. In that case, I can create an observable product from my product object like this: var observableProduct = WinJS.Binding.as(product); This line of code creates a new JavaScript object named observableProduct from the existing JavaScript object named product. This new object also has a name, description, and price property. However, unlike the properties of the original product object, the properties of the observable product object trigger notifications when the properties are changed. Each of the properties of the new observable product object has been changed into accessor properties which have both a getter and a setter. For example, the observable product price property looks something like this: price: { get: function () { return this.getProperty(“price”); } set: function (value) { this.setProperty(“price”, value); } } When you read the price property then the getProperty() method is called and when you set the price property then the setProperty() method is called. The getProperty() and setProperty() methods are methods of the observable product object. The observable product object supports the following methods and properties: · addProperty(name, value) – Adds a new property to an observable and notifies any listeners. · backingData – An object which represents the value of each property. · bind(name, action) – Enables you to execute a function when a property changes. · getProperty(name) – Returns the value of a property using the string name of the property. · notify(name, newValue, oldValue) – A private method which executes each function in the _listeners array. · removeProperty(name) – Removes a property and notifies any listeners. · setProperty(name, value) – Updates a property and notifies any listeners. · unbind(name, action) – Enables you to stop executing a function in response to a property change. · updateProperty(name, value) – Updates a property and notifies any listeners. So when you create an observable, you get a new object with the same properties as an existing object. However, when you modify the properties of an observable object, then you can notify any listeners of the observable that the value of a particular property has changed automatically. Imagine that you change the value of the price property like this: observableProduct.price = 2.99; In that case, the following sequence of events is triggered: 1. The price setter calls the setProperty(“price”, 2.99) method 2. The setProperty() method updates the value of the backingData.price property and calls the notify() method 3. The notify() method executes each function in the collection of listeners associated with the price property Creating Observable Listeners If you want to be notified when a property of an observable object is changed, then you need to register a listener. You register a listener by using the bind() method like this: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price observableProduct.price = 2.99; } }; app.start(); })(); In the code above, the bind() method is used to associate the price property with a function. When the price property is changed, the function logs the new value of the price property to the Visual Studio JavaScript console. The price property is associated with the function using the following line of code: // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); Coalescing Notifications If you make multiple changes to a property – one change immediately following another – then separate notifications won’t be sent. Instead, any listeners are notified only once. The notifications are coalesced into a single notification. For example, in the following code, the product price property is updated three times. However, only one message is written to the JavaScript console. Only the last value assigned to the price property is written to the JavaScript Console window: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price observableProduct.price = 3.99; observableProduct.price = 2.99; observableProduct.price = 1.99; Only the last value assigned to price, the value 1.99, appears in the console: If there is a time delay between changes to a property then changes result in different notifications. For example, the following code updates the price property every second: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Add 1 to price every second window.setInterval(function () { observableProduct.price += 1; }, 1000); In this case, separate notification messages are logged to the JavaScript Console window: If you need to prevent multiple notifications from being coalesced into one then you can take advantage of promises. I discussed WinJS promises in a previous blog entry: http://stephenwalther.com/blog/archive/2012/02/22/windows-web-applications-promises.aspx Because the updateProperty() method returns a promise, you can create different notifications for each change in a property by using the following code: // Change the price observableProduct.updateProperty("price", 3.99) .then(function () { observableProduct.updateProperty("price", 2.99) .then(function () { observableProduct.updateProperty("price", 1.99); }); }); In this case, even though the price is immediately changed from 3.99 to 2.99 to 1.99, separate notifications for each new value of the price property are sent. Bypassing Notifications Normally, if a property of an observable object has listeners and you change the property then the listeners are notified. However, there are certain situations in which you might want to bypass notification. In other words, you might need to change a property value silently without triggering any functions registered for notification. If you want to change a property without triggering notifications then you should change the property by using the backingData property. The following code illustrates how you can change the price property silently: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price silently observableProduct.backingData.price = 5.99; console.log(observableProduct.price); // Writes 5.99 The price is changed to the value 5.99 by changing the value of backingData.price. Because the observableProduct.price property is not set directly, any listeners associated with the price property are not notified. When you change the value of a property by using the backingData property, the change in the property happens synchronously. However, when you change the value of an observable property directly, the change is always made asynchronously. Summary The goal of this blog entry was to describe observables. In particular, we discussed how to create observables from existing JavaScript objects and bind functions to observable properties. You also learned how notifications are coalesced (and ways to prevent this coalescing). Finally, we discussed how you can use the backingData property to update an observable property without triggering notifications. In the next blog entry, we’ll see how observables are used with declarative binding to display the values of properties in an HTML document.

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  • Scripting with the Sun ZFS Storage 7000 Appliance

    - by Geoff Ongley
    The Sun ZFS Storage 7000 appliance has a user friendly and easy to understand graphical web based interface we call the "BUI" or "Browser User Interface".This interface is very useful for many tasks, but in some cases a script (or workflow) may be more appropriate, such as:Repetitive tasksTasks which work on (or obtain information about) a large number of shares or usersTasks which are triggered by an alert threshold (workflows)Tasks where you want a only very basic input, but a consistent output (workflows)The appliance scripting language is based on ECMAscript 3 (close to javascript). I'm not going to cover ECMAscript 3 in great depth (I'm far from an expert here), but I would like to show you some neat things you can do with the appliance, to get you started based on what I have found from my own playing around.I'm making the assumption you have some sort of programming background, and understand variables, arrays, functions to some extent - but of course if something is not clear, please let me know so I can fix it up or clarify it.Variable Declarations and ArraysVariablesECMAScript is a dynamically and weakly typed language. If you don't know what that means, google is your friend - but at a high level it means we can just declare variables with no specific type and on the fly.For example, I can declare a variable and use it straight away in the middle of my code, for example:projects=list();Which makes projects an array of values that are returned from the list(); function (which is usable in most contexts). With this kind of variable, I can do things like:projects.length (this property on array tells you how many objects are in it, good for for loops etc). Alternatively, I could say:projects=3;and now projects is just a simple number.Should we declare variables like this so loosely? In my opinion, the answer is no - I feel it is a better practice to declare variables you are going to use, before you use them - and given them an initial value. You can do so as follows:var myVariable=0;To demonstrate the ability to just randomly assign and change the type of variables, you can create a simple script at the cli as follows (bold for input):fishy10:> script("." to run)> run("cd /");("." to run)> run ("shares");("." to run)> var projects;("." to run)> projects=list();("." to run)> printf("Number of projects is: %d\n",projects.length);("." to run)> projects=152;("." to run)> printf("Value of the projects variable as an integer is now: %d\n",projects);("." to run)> .Number of projects is: 7Value of the projects variable as an integer is now: 152You can also confirm this behaviour by checking the typeof variable we are dealing with:fishy10:> script("." to run)> run("cd /");("." to run)> run ("shares");("." to run)> var projects;("." to run)> projects=list();("." to run)> printf("var projects is of type %s\n",typeof(projects));("." to run)> projects=152;("." to run)> printf("var projects is of type %s\n",typeof(projects));("." to run)> .var projects is of type objectvar projects is of type numberArraysSo you likely noticed that we have already touched on arrays, as the list(); (in the shares context) stored an array into the 'projects' variable.But what if you want to declare your own array? Easy! This is very similar to Java and other languages, we just instantiate a brand new "Array" object using the keyword new:var myArray = new Array();will create an array called "myArray".A quick example:fishy10:> script("." to run)> testArray = new Array();("." to run)> testArray[0]="This";("." to run)> testArray[1]="is";("." to run)> testArray[2]="just";("." to run)> testArray[3]="a";("." to run)> testArray[4]="test";("." to run)> for (i=0; i < testArray.length; i++)("." to run)> {("." to run)>    printf("Array element %d is %s\n",i,testArray[i]);("." to run)> }("." to run)> .Array element 0 is ThisArray element 1 is isArray element 2 is justArray element 3 is aArray element 4 is testWorking With LoopsFor LoopFor loops are very similar to those you will see in C, java and several other languages. One of the key differences here is, as you were made aware earlier, we can be a bit more sloppy with our variable declarations.The general way you would likely use a for loop is as follows:for (variable; test-case; modifier for variable){}For example, you may wish to declare a variable i as 0; and a MAX_ITERATIONS variable to determine how many times this loop should repeat:var i=0;var MAX_ITERATIONS=10;And then, use this variable to be tested against some case existing (has i reached MAX_ITERATIONS? - if not, increment i using i++);for (i=0; i < MAX_ITERATIONS; i++){ // some work to do}So lets run something like this on the appliance:fishy10:> script("." to run)> var i=0;("." to run)> var MAX_ITERATIONS=10;("." to run)> for (i=0; i < MAX_ITERATIONS; i++)("." to run)> {("." to run)>    printf("The number is %d\n",i);("." to run)> }("." to run)> .The number is 0The number is 1The number is 2The number is 3The number is 4The number is 5The number is 6The number is 7The number is 8The number is 9While LoopWhile loops again are very similar to other languages, we loop "while" a condition is met. For example:fishy10:> script("." to run)> var isTen=false;("." to run)> var counter=0;("." to run)> while(isTen==false)("." to run)> {("." to run)>    if (counter==10) ("." to run)>    { ("." to run)>            isTen=true;   ("." to run)>    } ("." to run)>    printf("Counter is %d\n",counter);("." to run)>    counter++;    ("." to run)> }("." to run)> printf("Loop has ended and Counter is %d\n",counter);("." to run)> .Counter is 0Counter is 1Counter is 2Counter is 3Counter is 4Counter is 5Counter is 6Counter is 7Counter is 8Counter is 9Counter is 10Loop has ended and Counter is 11So what do we notice here? Something has actually gone wrong - counter will technically be 11 once the loop completes... Why is this?Well, if we have a loop like this, where the 'while' condition that will end the loop may be set based on some other condition(s) existing (such as the counter has reached 10) - we must ensure that we  terminate this iteration of the loop when the condition is met - otherwise the rest of the code will be followed which may not be desirable. In other words, like in other languages, we will only ever check the loop condition once we are ready to perform the next iteration, so any other code after we set "isTen" to be true, will still be executed as we can see it was above.We can avoid this by adding a break into our loop once we know we have set the condition - this will stop the rest of the logic being processed in this iteration (and as such, counter will not be incremented). So lets try that again:fishy10:> script("." to run)> var isTen=false;("." to run)> var counter=0;("." to run)> while(isTen==false)("." to run)> {("." to run)>    if (counter==10) ("." to run)>    { ("." to run)>            isTen=true;   ("." to run)>            break;("." to run)>    } ("." to run)>    printf("Counter is %d\n",counter);("." to run)>    counter++;    ("." to run)> }("." to run)> printf("Loop has ended and Counter is %d\n", counter);("." to run)> .Counter is 0Counter is 1Counter is 2Counter is 3Counter is 4Counter is 5Counter is 6Counter is 7Counter is 8Counter is 9Loop has ended and Counter is 10Much better!Methods to Obtain and Manipulate DataGet MethodThe get method allows you to get simple properties from an object, for example a quota from a user. The syntax is fairly simple:var myVariable=get('property');An example of where you may wish to use this, is when you are getting a bunch of information about a user (such as quota information when in a shares context):var users=list();for(k=0; k < users.length; k++){     user=users[k];     run('select ' + user);     var username=get('name');     var usage=get('usage');     var quota=get('quota');...Which you can then use to your advantage - to print or manipulate infomation (you could change a user's information with a set method, based on the information returned from the get method). The set method is explained next.Set MethodThe set method can be used in a simple manner, similar to get. The syntax for set is:set('property','value'); // where value is a string, if it was a number, you don't need quotesFor example, we could set the quota on a share as follows (first observing the initial value):fishy10:shares default/test-geoff> script("." to run)> var currentQuota=get('quota');("." to run)> printf("Current Quota is: %s\n",currentQuota);("." to run)> set('quota','30G');("." to run)> run('commit');("." to run)> currentQuota=get('quota');("." to run)> printf("Current Quota is: %s\n",currentQuota);("." to run)> .Current Quota is: 0Current Quota is: 32212254720This shows us using both the get and set methods as can be used in scripts, of course when only setting an individual share, the above is overkill - it would be much easier to set it manually at the cli using 'set quota=3G' and then 'commit'.List MethodThe list method can be very powerful, especially in more complex scripts which iterate over large amounts of data and manipulate it if so desired. The general way you will use list is as follows:var myVar=list();Which will make "myVar" an array, containing all the objects in the relevant context (this could be a list of users, shares, projects, etc). You can then gather or manipulate data very easily.We could list all the shares and mountpoints in a given project for example:fishy10:shares another-project> script("." to run)> var shares=list();("." to run)> for (i=0; i < shares.length; i++)("." to run)> {("." to run)>    run('select ' + shares[i]);("." to run)>    var mountpoint=get('mountpoint');("." to run)>    printf("Share %s discovered, has mountpoint %s\n",shares[i],mountpoint);("." to run)>    run('done');("." to run)> }("." to run)> .Share and-another discovered, has mountpoint /export/another-project/and-anotherShare another-share discovered, has mountpoint /export/another-project/another-shareShare bob discovered, has mountpoint /export/another-projectShare more-shares-for-all discovered, has mountpoint /export/another-project/more-shares-for-allShare yep discovered, has mountpoint /export/another-project/yepWriting More Complex and Re-Usable CodeFunctionsThe best way to be able to write more complex code is to use functions to split up repeatable or reusable sections of your code. This also makes your more complex code easier to read and understand for other programmers.We write functions as follows:function functionName(variable1,variable2,...,variableN){}For example, we could have a function that takes a project name as input, and lists shares for that project (assuming we're already in the 'project' context - context is important!):function getShares(proj){        run('select ' + proj);        shares=list();        printf("Project: %s\n", proj);        for(j=0; j < shares.length; j++)        {                printf("Discovered share: %s\n",shares[i]);        }        run('done'); // exit selected project}Commenting your CodeLike any other language, a large part of making it readable and understandable is to comment it. You can use the same comment style as in C and Java amongst other languages.In other words, sngle line comments use://at the beginning of the comment.Multi line comments use:/*at the beginning, and:*/ at the end.For example, here we will use both:fishy10:> script("." to run)> // This is a test comment("." to run)> printf("doing some work...\n");("." to run)> /* This is a multi-line("." to run)> comment which I will span across("." to run)> three lines in total */("." to run)> printf("doing some more work...\n");("." to run)> .doing some work...doing some more work...Your comments do not have to be on their own, they can begin (particularly with single line comments this is handy) at the end of a statement, for examplevar projects=list(); // The variable projects is an array containing all projects on the system.Try and Catch StatementsYou may be used to using try and catch statements in other languages, and they can (and should) be utilised in your code to catch expected or unexpected error conditions, that you do NOT wish to stop your code from executing (if you do not catch these errors, your script will exit!):try{  // do some work}catch(err) // Catch any error that could occur{ // do something here under the error condition}For example, you may wish to only execute some code if a context can be reached. If you can't perform certain actions under certain circumstances, that may be perfectly acceptable.For example if you want to test a condition that only makes sense when looking at a SMB/NFS share, but does not make sense when you hit an iscsi or FC LUN, you don't want to stop all processing of other shares you may not have covered yet.For example we may wish to obtain quota information on all shares for all users on a share (but this makes no sense for a LUN):function getShareQuota(shar) // Get quota for each user of this share{        run('select ' + shar);        printf("  SHARE: %s\n", shar);        try        {                run('users');                printf("    %20s        %11s    %11s    %3s\n","Username","Usage(G)","Quota(G)","Quota(%)");                printf("    %20s        %11s    %11s    %4s\n","--------","--------","--------","----");                                users=list();                for(k=0; k < users.length; k++)                {                        user=users[k];                        getUserQuota(user);                }                run('done'); // exit user context        }        catch(err)        {                printf("    SKIPPING %s - This is NOT a NFS or CIFs share, not looking for users\n", shar);        }        run('done'); // done with this share}Running Scripts Remotely over SSHAs you have likely noticed, writing and running scripts for all but the simplest jobs directly on the appliance is not going to be a lot of fun.There's a couple of choices on what you can do here:Create scripts on a remote system and run them over sshCreate scripts, wrapping them in workflow code, so they are stored on the appliance and can be triggered under certain circumstances (like a threshold being reached)We'll cover the first one here, and then cover workflows later on (as these are for the most part just scripts with some wrapper information around them).Creating a SSH Public/Private SSH Key PairLog on to your handy Solaris box (You wouldn't be using any other OS, right? :P) and use ssh-keygen to create a pair of ssh keys. I'm storing this separate to my normal key:[geoff@lightning ~] ssh-keygen -t rsa -b 1024Generating public/private rsa key pair.Enter file in which to save the key (/export/home/geoff/.ssh/id_rsa): /export/home/geoff/.ssh/nas_key_rsaEnter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /export/home/geoff/.ssh/nas_key_rsa.Your public key has been saved in /export/home/geoff/.ssh/nas_key_rsa.pub.The key fingerprint is:7f:3d:53:f0:2a:5e:8b:2d:94:2a:55:77:66:5c:9b:14 geoff@lightningInstalling the Public Key on the ApplianceOn your Solaris host, observe the public key:[geoff@lightning ~] cat .ssh/nas_key_rsa.pub ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc= geoff@lightningNow, copy and paste everything after "ssh-rsa" and before "user@hostname" - in this case, geoff@lightning. That is, this bit:AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc=Logon to your appliance and get into the preferences -> keys area for this user (root):[geoff@lightning ~] ssh [email protected]: Last login: Mon Dec  6 17:13:28 2010 from 192.168.0.2fishy10:> configuration usersfishy10:configuration users> select rootfishy10:configuration users root> preferences fishy10:configuration users root preferences> keysOR do it all in one hit:fishy10:> configuration users select root preferences keysNow, we create a new public key that will be accepted for this user and set the type to RSA:fishy10:configuration users root preferences keys> createfishy10:configuration users root preferences key (uncommitted)> set type=RSASet the key itself using the string copied previously (between ssh-rsa and user@host), and set the key ensuring you put double quotes around it (eg. set key="<key>"):fishy10:configuration users root preferences key (uncommitted)> set key="AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc="Now set the comment for this key (do not use spaces):fishy10:configuration users root preferences key (uncommitted)> set comment="LightningRSAKey" Commit the new key:fishy10:configuration users root preferences key (uncommitted)> commitVerify the key is there:fishy10:configuration users root preferences keys> lsKeys:NAME     MODIFIED              TYPE   COMMENT                                  key-000  2010-10-25 20:56:42   RSA    cycloneRSAKey                           key-001  2010-12-6 17:44:53    RSA    LightningRSAKey                         As you can see, we now have my new key, and a previous key I have created on this appliance.Running your Script over SSH from a Remote SystemHere I have created a basic test script, and saved it as test.ecma3:[geoff@lightning ~] cat test.ecma3 script// This is a test script, By Geoff Ongley 2010.printf("Testing script remotely over ssh\n");.Now, we can run this script remotely with our keyless login:[geoff@lightning ~] ssh -i .ssh/nas_key_rsa root@fishy10 < test.ecma3Pseudo-terminal will not be allocated because stdin is not a terminal.Testing script remotely over sshPutting it Together - An Example Completed Quota Gathering ScriptSo now we have a lot of the basics to creating a script, let us do something useful, like, find out how much every user is using, on every share on the system (you will recognise some of the code from my previous examples): script/************************************** Quick and Dirty Quota Check script ** Written By Geoff Ongley            ** 25 October 2010                    **************************************/function getUserQuota(usr){        run('select ' + usr);        var username=get('name');        var usage=get('usage');        var quota=get('quota');        var usage_g=usage / 1073741824; // convert bytes to gigabytes        var quota_g=quota / 1073741824; // as above        var quota_percent=0        if (quota > 0)        {                quota_percent=(usage / quota)*(100/1);        }        printf("    %20s        %8.2f           %8.2f           %d%%\n",username,usage_g,quota_g,quota_percent);        run('done'); // done with this selected user}function getShareQuota(shar){        //printf("DEBUG: selecting share %s\n", shar);        run('select ' + shar);        printf("  SHARE: %s\n", shar);        try        {                run('users');                printf("    %20s        %11s    %11s    %3s\n","Username","Usage(G)","Quota(G)","Quota(%)");                printf("    %20s        %11s    %11s    %4s\n","--------","--------","--------","--------");                                users=list();                for(k=0; k < users.length; k++)                {                        user=users[k];                        getUserQuota(user);                }                run('done'); // exit user context        }        catch(err)        {                printf("    SKIPPING %s - This is NOT a NFS or CIFs share, not looking for users\n", shar);        }        run('done'); // done with this share}function getShares(proj){        //printf("DEBUG: selecting project %s\n",proj);        run('select ' + proj);        shares=list();        printf("Project: %s\n", proj);        for(j=0; j < shares.length; j++)        {                share=shares[j];                getShareQuota(share);        }        run('done'); // exit selected project}function getProjects(){        run('cd /');        run('shares');        projects=list();                for (i=0; i < projects.length; i++)        {                var project=projects[i];                getShares(project);        }        run('done'); // exit context for all projects}getProjects();.Which can be run as follows, and will print information like this:[geoff@lightning ~/FISHWORKS_SCRIPTS] ssh -i ~/.ssh/nas_key_rsa root@fishy10 < get_quota_utilisation.ecma3Pseudo-terminal will not be allocated because stdin is not a terminal.Project: another-project  SHARE: and-another                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                  nobody            0.00            0.00        0%                 geoffro            0.05            0.00        0%                   Billy            0.10            0.00        0%                    root            0.00            0.00        0%            testing-user            0.05            0.00        0%  SHARE: another-share                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                    root            0.00            0.00        0%                  nobody            0.00            0.00        0%                 geoffro            0.05            0.49        9%            testing-user            0.05            0.02        249%                   Billy            0.10            0.29        33%  SHARE: bob                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                  nobody            0.00            0.00        0%                    root            0.00            0.00        0%  SHARE: more-shares-for-all                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                   Billy            0.10            0.00        0%            testing-user            0.05            0.00        0%                  nobody            0.00            0.00        0%                    root            0.00            0.00        0%                 geoffro            0.05            0.00        0%  SHARE: yep                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                    root            0.00            0.00        0%                  nobody            0.00            0.00        0%                   Billy            0.10            0.01        999%            testing-user            0.05            0.49        9%                 geoffro            0.05            0.00        0%Project: default  SHARE: Test-LUN    SKIPPING Test-LUN - This is NOT a NFS or CIFs share, not looking for users  SHARE: test-geoff                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                 geoffro            0.05            0.00        0%                    root            3.18           10.00        31%                    uucp            0.00            0.00        0%                  nobody            0.59            0.49        119%^CKilled by signal 2.Creating a WorkflowWorkflows are scripts that we store on the appliance, and can have the script execute either on request (even from the BUI), or on an event such as a threshold being met.Workflow BasicsA workflow allows you to create a simple process that can be executed either via the BUI interface interactively, or by an alert being raised (for some threshold being reached, for example).The basics parameters you will have to set for your "workflow object" (notice you're creating a variable, that embodies ECMAScript) are as follows (parameters is optional):name: A name for this workflowdescription: A Description for the workflowparameters: A set of input parameters (useful when you need user input to execute the workflow)execute: The code, the script itself to execute, which will be function (parameters)With parameters, you can specify things like this (slightly modified sample taken from the System Administration Guide):          ...parameters:        variableParam1:         {                             label: 'Name of Share',                             type: 'String'                  },                  variableParam2                  {                             label: 'Share Size',                             type: 'size'                  },execute: ....};  Note the commas separating the sections of name, parameters, execute, and so on. This is important!Also - there is plenty of properties you can set on the parameters for your workflow, these are described in the Sun ZFS Storage System Administration Guide.Creating a Basic Workflow from a Basic ScriptTo make a basic script into a basic workflow, you need to wrap the following around your script to create a 'workflow' object:var workflow = {name: 'Get User Quotas',description: 'Displays Quota Utilisation for each user on each share',execute: function() {// (basic script goes here, minus the "script" at the beginning, and "." at the end)}};However, it appears (at least in my experience to date) that the workflow object may only be happy with one function in the execute parameter - either that or I'm doing something wrong. As far as I can tell, after execute: you should only have a basic one function context like so:execute: function(){}To deal with this, and to give an example similar to our script earlier, I have created another simple quota check, to show the same basic functionality, but in a workflow format:var workflow = {name: 'Get User Quotas',description: 'Displays Quota Utilisation for each user on each share',execute: function () {        run('cd /');        run('shares');        projects=list();                for (i=0; i < projects.length; i++)        {                run('select ' + projects[i]);                shares=list('filesystem');                printf("Project: %s\n", projects[i]);                for(j=0; j < shares.length; j++)                {                        run('select ' +shares[j]);                        try                        {                                run('users');                                printf("  SHARE: %s\n", shares[j]);                                printf("    %20s        %11s    %11s    %3s\n","Username","Usage(G)","Quota(G)","Quota(%)");                                printf("    %20s        %11s    %11s    %4s\n","--------","--------","--------","-------");                                users=list();                                for(k=0; k < users.length; k++)                                {                                        run('select ' + users[k]);                                        username=get('name');                                        usage=get('usage');                                        quota=get('quota');                                        usage_g=usage / 1073741824; // convert bytes to gigabytes                                        quota_g=quota / 1073741824; // as above                                        quota_percent=0                                        if (quota > 0)                                        {                                                quota_percent=(usage / quota)*(100/1);                                        }                                        printf("    %20s        %8.2f   %8.2f   %d%%\n",username,usage_g,quota_g,quota_percent);                                        run('done');                                }                                run('done'); // exit user context                        }                        catch(err)                        {                        //      printf("    %s is a LUN, Not looking for users\n", shares[j]);                        }                        run('done'); // exit selected share context                }                run('done'); // exit project context        }        }};SummaryThe Sun ZFS Storage 7000 Appliance offers lots of different and interesting features to Sun/Oracle customers, including the world renowned Analytics. Hopefully the above will help you to think of new creative things you could be doing by taking advantage of one of the other neat features, the internal scripting engine!Some references are below to help you continue learning more, I'll update this post as I do the same! Enjoy...More information on ECMAScript 3A complete reference to ECMAScript 3 which will help you learn more of the details you may be interested in, can be found here:http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdfMore Information on Administering the Sun ZFS Storage 7000The Sun ZFS Storage 7000 System Administration guide can be a useful reference point, and can be found here:http://wikis.sun.com/download/attachments/186238602/2010_Q3_2_ADMIN.pdf

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  • A DirectoryCatalog class for Silverlight MEF (Managed Extensibility Framework)

    - by Dixin
    In the MEF (Managed Extension Framework) for .NET, there are useful ComposablePartCatalog implementations in System.ComponentModel.Composition.dll, like: System.ComponentModel.Composition.Hosting.AggregateCatalog System.ComponentModel.Composition.Hosting.AssemblyCatalog System.ComponentModel.Composition.Hosting.DirectoryCatalog System.ComponentModel.Composition.Hosting.TypeCatalog While in Silverlight, there is a extra System.ComponentModel.Composition.Hosting.DeploymentCatalog. As a wrapper of AssemblyCatalog, it can load all assemblies in a XAP file in the web server side. Unfortunately, in silverlight there is no DirectoryCatalog to load a folder. Background There are scenarios that Silverlight application may need to load all XAP files in a folder in the web server side, for example: If the Silverlight application is extensible and supports plug-ins, there would be a /ClinetBin/Plugins/ folder in the web server, and each pluin would be an individual XAP file in the folder. In this scenario, after the application is loaded and started up, it would like to load all XAP files in /ClinetBin/Plugins/ folder. If the aplication supports themes, there would be a /ClinetBin/Themes/ folder, and each theme would be an individual XAP file too. The application would qalso need to load all XAP files in /ClinetBin/Themes/. It is useful if we have a DirectoryCatalog: DirectoryCatalog catalog = new DirectoryCatalog("/Plugins"); catalog.DownloadCompleted += (sender, e) => { }; catalog.DownloadAsync(); Obviously, the implementation of DirectoryCatalog is easy. It is just a collection of DeploymentCatalog class. Retrieve file list from a directory Of course, to retrieve file list from a web folder, the folder’s “Directory Browsing” feature must be enabled: So when the folder is requested, it responses a list of its files and folders: This is nothing but a simple HTML page: <html> <head> <title>localhost - /Folder/</title> </head> <body> <h1>localhost - /Folder/</h1> <hr> <pre> <a href="/">[To Parent Directory]</a><br> <br> 1/3/2011 7:22 PM 185 <a href="/Folder/File.txt">File.txt</a><br> 1/3/2011 7:22 PM &lt;dir&gt; <a href="/Folder/Folder/">Folder</a><br> </pre> <hr> </body> </html> For the ASP.NET Deployment Server of Visual Studio, directory browsing is enabled by default: The HTML <Body> is almost the same: <body bgcolor="white"> <h2><i>Directory Listing -- /ClientBin/</i></h2> <hr width="100%" size="1" color="silver"> <pre> <a href="/">[To Parent Directory]</a> Thursday, January 27, 2011 11:51 PM 282,538 <a href="Test.xap">Test.xap</a> Tuesday, January 04, 2011 02:06 AM &lt;dir&gt; <a href="TestFolder/">TestFolder</a> </pre> <hr width="100%" size="1" color="silver"> <b>Version Information:</b>&nbsp;ASP.NET Development Server 10.0.0.0 </body> The only difference is, IIS’s links start with slash, but here the links do not. Here one way to get the file list is read the href attributes of the links: [Pure] private IEnumerable<Uri> GetFilesFromDirectory(string html) { Contract.Requires(html != null); Contract.Ensures(Contract.Result<IEnumerable<Uri>>() != null); return new Regex( "<a href=\"(?<uriRelative>[^\"]*)\">[^<]*</a>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant) .Matches(html) .OfType<Match>() .Where(match => match.Success) .Select(match => match.Groups["uriRelative"].Value) .Where(uriRelative => uriRelative.EndsWith(".xap", StringComparison.Ordinal)) .Select(uriRelative => { Uri baseUri = this.Uri.IsAbsoluteUri ? this.Uri : new Uri(Application.Current.Host.Source, this.Uri); uriRelative = uriRelative.StartsWith("/", StringComparison.Ordinal) ? uriRelative : (baseUri.LocalPath.EndsWith("/", StringComparison.Ordinal) ? baseUri.LocalPath + uriRelative : baseUri.LocalPath + "/" + uriRelative); return new Uri(baseUri, uriRelative); }); } Please notice the folders’ links end with a slash. They are filtered by the second Where() query. The above method can find files’ URIs from the specified IIS folder, or ASP.NET Deployment Server folder while debugging. To support other formats of file list, a constructor is needed to pass into a customized method: /// <summary> /// Initializes a new instance of the <see cref="T:System.ComponentModel.Composition.Hosting.DirectoryCatalog" /> class with <see cref="T:System.ComponentModel.Composition.Primitives.ComposablePartDefinition" /> objects based on all the XAP files in the specified directory URI. /// </summary> /// <param name="uri"> /// URI to the directory to scan for XAPs to add to the catalog. /// The URI must be absolute, or relative to <see cref="P:System.Windows.Interop.SilverlightHost.Source" />. /// </param> /// <param name="getFilesFromDirectory"> /// The method to find files' URIs in the specified directory. /// </param> public DirectoryCatalog(Uri uri, Func<string, IEnumerable<Uri>> getFilesFromDirectory) { Contract.Requires(uri != null); this._uri = uri; this._getFilesFromDirectory = getFilesFromDirectory ?? this.GetFilesFromDirectory; this._webClient = new Lazy<WebClient>(() => new WebClient()); // Initializes other members. } When the getFilesFromDirectory parameter is null, the above GetFilesFromDirectory() method will be used as default. Download the directory’s XAP file list Now a public method can be created to start the downloading: /// <summary> /// Begins downloading the XAP files in the directory. /// </summary> public void DownloadAsync() { this.ThrowIfDisposed(); if (Interlocked.CompareExchange(ref this._state, State.DownloadStarted, State.Created) == 0) { this._webClient.Value.OpenReadCompleted += this.HandleOpenReadCompleted; this._webClient.Value.OpenReadAsync(this.Uri, this); } else { this.MutateStateOrThrow(State.DownloadCompleted, State.Initialized); this.OnDownloadCompleted(new AsyncCompletedEventArgs(null, false, this)); } } Here the HandleOpenReadCompleted() method is invoked when the file list HTML is downloaded. Download all XAP files After retrieving all files’ URIs, the next thing becomes even easier. HandleOpenReadCompleted() just uses built in DeploymentCatalog to download the XAPs, and aggregate them into one AggregateCatalog: private void HandleOpenReadCompleted(object sender, OpenReadCompletedEventArgs e) { Exception error = e.Error; bool cancelled = e.Cancelled; if (Interlocked.CompareExchange(ref this._state, State.DownloadCompleted, State.DownloadStarted) != State.DownloadStarted) { cancelled = true; } if (error == null && !cancelled) { try { using (StreamReader reader = new StreamReader(e.Result)) { string html = reader.ReadToEnd(); IEnumerable<Uri> uris = this._getFilesFromDirectory(html); Contract.Assume(uris != null); IEnumerable<DeploymentCatalog> deploymentCatalogs = uris.Select(uri => new DeploymentCatalog(uri)); deploymentCatalogs.ForEach( deploymentCatalog => { this._aggregateCatalog.Catalogs.Add(deploymentCatalog); deploymentCatalog.DownloadCompleted += this.HandleDownloadCompleted; }); deploymentCatalogs.ForEach(deploymentCatalog => deploymentCatalog.DownloadAsync()); } } catch (Exception exception) { error = new InvalidOperationException(Resources.InvalidOperationException_ErrorReadingDirectory, exception); } } // Exception handling. } In HandleDownloadCompleted(), if all XAPs are downloaded without exception, OnDownloadCompleted() callback method will be invoked. private void HandleDownloadCompleted(object sender, AsyncCompletedEventArgs e) { if (Interlocked.Increment(ref this._downloaded) == this._aggregateCatalog.Catalogs.Count) { this.OnDownloadCompleted(e); } } Exception handling Whether this DirectoryCatelog can work only if the directory browsing feature is enabled. It is important to inform caller when directory cannot be browsed for XAP downloading. private void HandleOpenReadCompleted(object sender, OpenReadCompletedEventArgs e) { Exception error = e.Error; bool cancelled = e.Cancelled; if (Interlocked.CompareExchange(ref this._state, State.DownloadCompleted, State.DownloadStarted) != State.DownloadStarted) { cancelled = true; } if (error == null && !cancelled) { try { // No exception thrown when browsing directory. Downloads the listed XAPs. } catch (Exception exception) { error = new InvalidOperationException(Resources.InvalidOperationException_ErrorReadingDirectory, exception); } } WebException webException = error as WebException; if (webException != null) { HttpWebResponse webResponse = webException.Response as HttpWebResponse; if (webResponse != null) { // Internally, WebClient uses WebRequest.Create() to create the WebRequest object. Here does the same thing. WebRequest request = WebRequest.Create(Application.Current.Host.Source); Contract.Assume(request != null); if (request.CreatorInstance == WebRequestCreator.ClientHttp && // Silverlight is in client HTTP handling, all HTTP status codes are supported. webResponse.StatusCode == HttpStatusCode.Forbidden) { // When directory browsing is disabled, the HTTP status code is 403 (forbidden). error = new InvalidOperationException( Resources.InvalidOperationException_ErrorListingDirectory_ClientHttp, webException); } else if (request.CreatorInstance == WebRequestCreator.BrowserHttp && // Silverlight is in browser HTTP handling, only 200 and 404 are supported. webResponse.StatusCode == HttpStatusCode.NotFound) { // When directory browsing is disabled, the HTTP status code is 404 (not found). error = new InvalidOperationException( Resources.InvalidOperationException_ErrorListingDirectory_BrowserHttp, webException); } } } this.OnDownloadCompleted(new AsyncCompletedEventArgs(error, cancelled, this)); } Please notice Silverlight 3+ application can work either in client HTTP handling, or browser HTTP handling. One difference is: In browser HTTP handling, only HTTP status code 200 (OK) and 404 (not OK, including 500, 403, etc.) are supported In client HTTP handling, all HTTP status code are supported So in above code, exceptions in 2 modes are handled differently. Conclusion Here is the whole DirectoryCatelog’s looking: Please click here to download the source code, a simple unit test is included. This is a rough implementation. And, for convenience, some design and coding are just following the built in AggregateCatalog class and Deployment class. Please feel free to modify the code, and please kindly tell me if any issue is found.

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