Apress Introducing dot NET 4 0 with Visual Studio 2010_5 pot

CHAPTER 10  ASP.NET 237 One-Click Publishing One-click publishing uses IIS remote management services to allow you to publish your application to a remote server with one click. One-click publishing only deploys files that have changed, so is very efficient. To use one-click publishing, you will need a hoster that supports One Click (at the time of writing Discount ASP or OrcsWeb) or, if deploying to your own server, to have IIS remote management services enabled (http://technet.microsoft.com/en-us/library/cc731771(WS.10).aspx). One Click is also only available for projects in the VS2010 format. Before we can use one-click publishing we need to configure a number of settings. Right-click on your project and select the Publish option. You will see a screen similar to Figure 10.4. Figure 10-4. One-click publishing profile settings Fill in the details as shown (using MSDeploy Publish as the Publish Method) and click Close. Once these details are completed, you can publish your application by selecting the Publish Profile you want to use from the drop-down menu (top left-hand side of the VS2010 screen) and clicking the Publish button (Figure 10-5). Note if this tool bar is not showing, right-click on the toolbar and select Web One Click Publish. VS2010 allows a single project to contain up to 50 different one click publishing profiles. CHAPTER 10  ASP.NET 238 Figure 10-5. Initiating one-click publishing ViewState ViewState is the mechanism by which ASP.NET stores the state of controls on a web form. This information is held in a hidden form value called __VIEWSTATE. Depending on the page’s content, ViewState can get pretty large, and is often unnecessary for controls that don’t change such as labels. ASP.NET 4.0 gives you the ability for controls to inherit ViewState settings from parent controls by using the new ViewStateMode property. This makes it very easy to efficiently set ViewStateMode on a large number of controls. ViewStateMode has three settings • Enabled (ViewState used) • Disabled (ViewState not used) • Inherit (ViewStateMode is inherited from parent control) The following example shows how to make lbl1 Label inherit pnlParent's ViewStateMode. <asp:Panel ID=”pnlParent” runat=server ViewStateMode=Disabled> <asp:Label ID="lbl1" Text="text" ViewStateMode=Inherit runat="server" /> </asp:Panel> CHAPTER 10  ASP.NET 239 ClientIDMode A long-term irritation in ASP.NET is the lack of control you have over the ID property of rendered controls. For example, take the following HTML that is rendered from a few simple controls that are nested inside a Master page: <span id="MainContent_label1"></span> <div id="MainContent_panel1"> <span id="MainContent_label2"></span> </div> Most of the time, ASP.NET’s automatic ID generation features work pretty well, but in some situations, say, when working with Master pages or writing client script, you need a finer level of control. ASP.NET 4.0 gives you this control with the new ClientIDMode. ClientIDMode has four settings • AutoID: Works as per previous ASP.NET releases. • Static: Allows you to specify the ID that is used. Warning: you can obviously generate duplicate client IDs, so it is up to you to ensure your ID is unique or face client-side script hell (well, probably an annoying JavaScript error, anyway). • Predictable: Used in conjunction with RowClientIdSuffix property to generate incrementing IDs for repeating controls such as DataGrid and Repeater, for example, myrow1, myrow2, myrow3. • Inherit: Controls uses the same ClientIDMode as its parent control (default). ClientIdMode can be set at control, page, and application level. • To set on an individual control: <asp:Label ID="lblTest" runat="server" Text="Test" ClientIdMode=”Inherit”></asp:Label> • At page level: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" ClientIdMode="Predictable" %> • Or application wide in Web.config: <system.web> <pages clientIdMode="Inherit"></pages> </system.web> Response.RedirectPermanent() Response.Redirect() is a frequently used method that redirects the current request to another URL. At an HTTP level Response.Redirect() issues a temporary redirect (HTTP 302) message to the user’s browser. ASP.NET 4.0 now offers a new Response.RedirectPermanent() method that issues a permanently moved (HTTP 301) message (http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html). Why bother? HTTP 301 is mainly used to tell search engines that they should save the new page location in their indexes rather than the old location. This saves an unnecessary trip to the server. Response.RedirectPermanent() usage is very similar to Response.Redirect(): CHAPTER 10  ASP.NET 240 Response.RedirectPermanent("/newpath/foroldcontent.aspx"); Meta-tags ASP.NET 4.0’s Page class has two new properties that allow you to set the keyword and description Meta- tags that are generated: MetaKeywords and MetaDescription properties. It is worth noting that most search engines (or certainly the big one beginning with G) probably ignore meta-tags (due to previous abuse), and that if you have already specified meta-tags on your page then MetaKeywords and MetaDescription will act as properties so make sure you append rather than overwrite when using them. URL Routing Routing was first introduced in ASP.net in .net 3.5sp1 and further enhanced in ASP.NET MVC (see Chapter 13). Routing allows you to map a URL to a physical file, which may or may not exist. To implement this functionality in previous versions of ASP.NET complex hacks or ISAPI filters were needed. Why use this feature? Well let’s say you are working for an online shop that has a new product they are advertising on TV and it is located at the following URL: www.myshop.com/productDetail.aspx?id=34534 Routing allows you to create a more readable URI mapped through to the page, such as: www.myshop.com/PopularProduct/ URL routing also allows you to create more memorable and search engine-friendly URIs, hiding the internal structure of your application. Routes are created in the Global.asax file. The code below maps the URL ~/PopularProduct to the page ~/default.aspx?id=34534: protected void Application_Start(object sender, EventArgs e) { System.Web.Routing.RouteTable.Routes.MapPageRoute( "myPopularRoute", "PopularProduct", "~/default.aspx?id=34534" ); } Routing has implications for security policies that you may have defined in Web.config, because ASP.NET will check policies for the route rather than mapped page. To remedy this, MapPageRoute supports an overloaded method that allows you to check that the user has access to the physical file (~/default.aspx?id=34534) as well. Access for defined routes is always checked. As well as creating simple one-to-one mapping URLs, it is useful to be able to pass in parameters to routes. For example most shops sell a number of different types of products so you could create URLs such as myshop.com/cats or myshop.com/dogs (note selling cats and dogs online is probably a bad idea). To create these type of routes enclose the value that will change inside curly brackets: System.Web.Routing.RouteTable.Routes.MapPageRoute( "myProductGroupRoute", "{groups}", "~/default.aspx?id=123" ); CHAPTER 10  ASP.NET 241 Routing parameters can then be retrieved with the following syntax: string searchTerm=Page.RouteData.Values["group"]; Sometimes it can also be useful to retrieve the URL that will be generated for a specific route to create hyperlinks or redirect the user; this can be done with the GetRouteUrl() method: Page.GetRouteUrl("myProductGroupRoute", new { group = "brandNew" }) HTML Encoding All web developers should be aware that it is important to HTML encode values that are output to prevent XSS attacks (particularly if you have received them from the user). ASP.NET 4.0 offers a new markup syntax that uses the colon character to tell ASP.NET to HTML encode the expression: <%: "<script>alert('I wont be run');</script>" %> When ASP.NET parses this it does the following: <%= HttpUtility.HtmlEncode(YourVariableHere) %> It is important to bear in mind that the use of this syntax may not negate all XSS attacks if you have complex nested HTML or JavaScript. HtmlString ASP.NET 4.0 includes the new HtmlString class that indicates an expression is already properly encoded and should not be re-examined. This prevents “safe” values from potentially firing dangerous request validation rules: <%: new HtmlString("<script>alert('I will now be run');</script>") %> Custom Request Validation It is now possible to override the default request validators by inheriting from the System.Web.Util.RequestValidator class and overriding the method IsValidRequestString(). You must then specify the custom validator in the httpRuntime section in Web.config: <httpRuntime requestValidationType="Apress.MyValidator, Samples" /> Custom Encoders If you feel that ASP.NET’s existing page encoders are insufficient then you can now create your own by inheriting from System.Web.Util.HttpEncoder class and specifying the new encoder in the encoderType attribute of httpRuntime, for example: <httpRuntime encoderType= =" Apress.MyEncoder, Samples" " /> CHAPTER 10  ASP.NET 242 URL and Query String Length Previously ASP.NET limited accepted URLs to a maximum of 260 characters (an NTFS constraint). ASP.NET 4.0 allows you to extend (or limit) the URL and query string maximum length. To modify these settings change the maxRequestPathLength and maxQueryStringLength properties (in the httpRuntime section) in Web.config: <httpRuntime maxQueryStringLength="260" maxRequestLength="2048"/> Valid URL Characters Previous versions of ASP.NET limit accepted URLs to a specific set of characters. The following characters were considered invalid in a URL: <, >, &. You can use the new requestPathInvalidChars property to specify invalid characters (such as the above). The below example makes a,b,c invalid in requests (which isn’t too useful but demonstrates the feature): <httpRuntime requestPathInvalidCharacters="a,b,c">  NOTE The Microsoft documentation states that ASP.NET 4.0 will reject paths with characters in ASCII range 0x00 to 0x1F (RFC 2396). Accessibility and Standards Accessibility and standards, whether you like it or not, are becoming increasingly important. Microsoft is aware of this and has introduced a number of changes. controlRenderingCompatibilityVersion The pages section in Web.config contains a new controlRenderingCompatibilityVersion property that determines how controls are rendered by default. The controlRenderingCompatibilityVersion property can be set to 3.5 or 4.0. <system.web> <pages controlRenderingCompatibilityVersion="4.0"/> </system.web> Setting controlRenderingCompatibilityVersion to 3.5 will ensure ASP.NET renders as in ASP.NET 3.5. If however you set controlRenderingCompatibilityVersion to 4.0 then Microsoft say that the following will occur: • The xhtmlConformance property will be set to Strict and controls will be rendered according to XHTML 1.0 Strict markup. • Disabled controls will not have invalid styles rendered. CHAPTER 10  ASP.NET 243 • Hidden fields that have div elements around them will now be styled in a manner that will not interfere with user-defined CSS rules. • Menu controls are now rendered using unordered list (UL) tags (fantastic). • Validation controls will not use inline styles. • Previously some controls such as Image rendered the property border="0"; this will no longer occur. RenderOuterTable Previous versions of ASP.NET used a Table tag to wrap the following controls: • ChangePassword • FormView • Login • PasswordRecovery In ASP.NET 4.0, however, all these controls support a new RenderOuterTable property that if set to false will use a div instead. CheckBoxList and RadioButtonList CheckBoxList and RadioButtonList benefit from a the new property RepeatLayout. RepeatLayout has four modes: UnorderedList, OrderedList, Flow, and Table, allowing you fine control over how they are rendered. ASP.NET Menu control The ASP.NET Menu control now renders menu items using unordered list elements. Keyboard support for the menu has also been improved so once an ASP.NET menu receives focus the user can navigate through menu items using the arrow keys. Browser Capability Files Browser capability files are used to determine how best to render content for individual browsers and are held in XML format. If you feel the need you can create your own browser provider by deriving from the HttpCapabilitiesProvider class. CHAPTER 10  ASP.NET 244 Further Control Enhancements There are a number of control enhancements, and a couple of miscellaneous new controls as well. Wizard Control The Wizard control now contains new templating functionality (LayoutTemplate). ListView Enhancements In previous versions of ASP.NET, when a row was selected within a ListView (or GridView) and the user moved to another page, the selection was maintained on the next page. This can be bad news if you then use this selection to perform an action on the selected record. ASP.NET 4.0 resolves this problem with the new EnablePersistedSelection property. If EnablePersistedSelection is set to True, then row selection is maintained using the datakey of each item. Another welcome change is that the declaration of ListViews has been much simplified. The following code shows how a ListView control had to be declared previously: <asp:ListView ID="lstView" runat="server"> <LayoutTemplate> <asp:PlaceHolder ID="itemPlaceholder" runat="server"></asp:PlaceHolder> </LayoutTemplate> <ItemTemplate> <%# Eval("firstname")%> </ItemTemplate> </asp:ListView> ASP.NET 4.0 allows you to do the following: <asp:ListView ID="ListView1" runat="server"> <ItemTemplate> <%# Eval("firstname") %> </ItemTemplate> </asp:ListView> GridView The GridView control now supports persisted selection (see previous example) and offers the ability to style header columns when they are sorted and contains improved support for working with ViewState disabled. CompareValidator The CompareValidator now supports the comparison of Time and DateTime values. CHAPTER 10  ASP.NET 245 Query Extender Query extender is a new control that aims to make the filtering of data easier by providing a declarative query syntax that you can link to the Entity or LinqDataSource controls. Browser capability files Browser capability files are to determine how best to render content for individual browsers and are held in XML format. If you feel the need (perhaps to override the rendering capabilities for iPhones, for example) you can create your own browser provider by deriving from the HttpCapabilitiesProvider class. Auto-Start Web Applications Some ASP.NET applications perform a lot of startup work (usually in Global.asax’s Application_Load() method). For example, preloading or caching data. ASP.NET 4.0 introduces a new feature called auto- start that enables you to define code to be run as soon as your application is installed (or the app pool is recycled). Until this startup work has completed ASP.NET will prevent access to the application. Not all applications will be able to benefit from this facility through as they must • Be running on Windows Server 2008 R2 and IIS 7.5. • Be written in ASP.NET 4.0. • To use add the setting below to the applicationHost.config file (held at C:\Windows\System32\inetsrv\config\): <applicationPools> <add name="ApressAppPool" startMode="AlwaysRunning"" /> </applicationPools> You must now specify the sites to be automatically started and the serviceAutoStartProvider they should use: <sites> <site name="ApressSite" id="5"> <application path="/" serviceAutoStartEnabled ="true" serviceAutoStartProvider ="PrewarmMyCache" > </application> </site> </sites> An auto start class is created by implementing the IProcessHostPreloadClient interface and added as a provider in applicationHost.config: <serviceAutoStartProviders > <add name="StartmeUp" type="Apress.CustomInitialization, ASPStartup" /> </serviceAutoStartProviders > CHAPTER 10  ASP.NET 246 Compress Session State It is generally a good rule to avoid storing anything in session unless absolutely necessary but if you must ASP.NET 4.0 allows you to compress session state. Session state compression cannot be used by an in- process session so is only applicable if your application is using state or SQL Server. To compress session simply set the compressionEnabled property to true in Web.config: <sessionState compressionEnabled="true"></sessionState> Session state is compressed using the GZip algorithm. It is important to note that compressing session requires a server to do more work so could adversely impact on the performance of your application. Caching ASP.NET 4.0 gives you the option to create and utilize custom cache providers. The cache provider can be set at an application, control, and even individual request level (by overriding the GetOutputCacheProviderName() method) offering very fine grained control. To create your own cache provider you must inherit from System.Web.Caching.OutputCacheProvider. Velocity Before you create your own caching system (you crazy fool), you would be wise to take a look into Microsoft’s new free distributed caching system, Velocity. Velocity provides a huge amount of functionality and is easily utilized by both web and Windows applications. Velocity presents a view of the cache that can be spread out amongst many machines and accessed by any type of application. For more information please refer to: http://msdn.microsoft.com/en-au/library/cc645013.aspx. System.Runtime.Caching In previous versions of .NET, caching functionality was contained in the System.Web assembly. To enable easier integration for non-web clients, Microsoft has created the new System.Runtime.Caching assembly. System.Runtime.Caching contains abstract classes for creating your own cache provider, and a new class called MemoryCache. MemoryCache can be used by non-web clients and offers simple in memory caching functionality. Microsoft say that the internal implementation of MemoryCache is very similar to ASP.NET’s cache. The following example shows how to utilize MemoryCache to store a string for an hour (note you can also create watchers to invalidate the cache if an item changes and add them to the policy.ChangeMonitors property): ObjectCache cache = MemoryCache.Default; string testData = cache["someData"] as string; if (testData == null) { CacheItemPolicy policy = new CacheItemPolicy(); policy.AbsoluteExpiration = new DateTimeOffset(DateTime.Now.AddHours(1)); cache.Set("someData", "some test data", policy); } [...]... occurs (see http://seejoelprogram.wordpress.com/ 200 8/ 10/ 03/fixingsysapplicationinitialize-again/) Installation A number of Visual Studio 201 0 project templates such as ASP .NET MVC 2 and ASP .NET web application projects include the Microsoft AJAX libraries out of the box The libraries will, however, be maintained separately from Visual Studio/ .NET 4. 0, so to obtain the latest release you will need to... 10 ASP .NET The following code binds a series of random points to the chart: Random r = new Random(); Series series = new Series("Line"); series.ChartType = SeriesChartType.Line; for (int i = 0; i < 100 ; i++) { series.Points.AddY(r.Next (0, 100 )); } chart1.Series.Add(series); Dynamic Data Framework It is worth noting that the Dynamic Data Framework has a number of additions in VS 201 0/ASP .NET 4. 0 I will... AJAX site has an example of how to call a JSONP service at http://www.asp .net/ ajaxlibrary/HOW%20TO%20Use%20JSONP%20to%20Request%20Data%20from%20Remote%20Websites.ashx For more information on JSONP, please refer to the following links: • http://ajaxian.com/archives/jsonp-json -with- padding • http://www.west-wind.com/Weblog/posts/ 107 136.aspx Advanced Binding Hopefully, by now you are excited about how... whatever platform they are developing for Further Reading • • http://www.asp .net/ ajaxlibrary/ • http://www.jamessenior.com/ • 2 70 http://ajax.codeplex.com/ http://weblogs.asp .net/ fredriknormen/archive/ 200 9 /09 /11/asp -net- ajax -4- 0preview-5-available.aspx CHAPTER 12 jQuery Availability: Any IntelliSens e Support fr om V isual Studio 200 8 Onwar d “jQuery is a fast and concise JavaScript Library that simplifies... 10- 6 New perf counters for ASP .NET 247 CHAPTER 10 ASP .NET Charting Controls Microsoft purchased and integrated the Dundas ASP .NET charting controls in early 200 8 This set contains over 35 different types of charts and a huge amount of functionality, some of which is shown in Figure 10- 7 Previously these controls had to be installed as an add-on and a number of settings added to Web.config ASP .NET 4. 0, ... setting to Aspnet.config (Aspnet.config is located where the NET framework is installed: C:\Windows\Microsoft .NET\ Framework\v4 .0. 2 100 6): When you have added this line go into perfmon and you should find that you will have access to two new performance counters in the ASP .NET applications performance category section (Figure 10. 6): • Managed... Assembly="System.Web.DataVisualization, Version =4. 0. 0 .0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" Namespace="System.Web.UI.DataVisualization.Charting" TagPrefix="asp" %> Charts are then added to the page with the following code: 248 CHAPTER 10. .. interesting to see if this remains the case in years to come Further Reading • http://www.asp .net/ LEARN/whitepapers/aspnet4/default.aspx 249 CHAPTER 11 Microsoft AJAX Library Visual Studio 201 0 includes a new version of the Microsoft AJAX libraries that can be used in any web application When working with the Microsoft AJAX library, many developers believe that it consists of little more than the UpdatePanel,... version of the AJAX libraries when this post was written): http://serialseb.blogspot.com/ 200 9 /06 /in-how-manyways-can-microsoft-ajax -4. html Hello, Microsoft AJAX It’s time to look at the new DataView functionality, so let’s create a new empty ASP .NET web project called Chapter11.HelloAjax 1 Create a directory called Scripts within your project 2 Download the latest AJAX libraries from http://ajax.codeplex.com/... http://www.asp .net/ dynamicdata Conclusion ASP .NET 4. 0 fixes some long-term omissions and bugs and looks likely to continue to be a popular method of developing web applications Alternative approaches such as ASP .NET MVC (Chapter 13) are gaining ground (due in part to their easy testability), so it will be interesting to see if this remains the case in years to come Further Reading • http://www.asp .net/ LEARN/whitepapers/aspnet4/default.aspx . http://seejoelprogram.wordpress.com/ 200 8/ 10/ 03/fixing- sysapplicationinitialize-again/). Installation A number of Visual Studio 201 0 project templates such as ASP .NET MVC 2 and ASP .NET web application projects. number of additions in VS 201 0/ASP .NET 4. 0. I will not be covering these but for interested readers please refer to: http://www.asp .net/ dynamicdata. Conclusion ASP .NET 4. 0 fixes some long-term. come. Further Reading • http://www.asp .net/ LEARN/whitepapers/aspnet4/default.aspx CHAPTER 11    251 Microsoft AJAX Library Visual Studio 201 0 includes a new version of the Microsoft