Navigation

	Home Page
	Index
	All Pages

Quick Search
Advanced Search »

Contributor Links

	Create a new Page
	Administration
	File Management
	Login/Logout
	Your Profile

Other Wiki Sections

Software

Chapter 02: Using Master Pages, Themes, and Caching - MCTS Exam 70-515

Table of Contents [Hide/Show]    Lesson 1: Using Master Pages       Master Page       Content Page       Programmatically Changing a Master Page    Lesson 2: Using Themes       Contents       Creation       Application       Creating a Skin          Types of Skins          Restrictions          Sample Skin Content       Precedence Rules for Applying Themes       Disabling a Theme       Applying a Theme Programmatically    Lesson 3: Caching       Application Caching          Overview          Inserting Items       Page Output Caching          Declarative Configuration          Partial-Page Caching          Programmatic Caching          Using Substitution to Update Caches       Programmatically Invalidating Cached Pages          Determining Whether to Return a Cached Page Prior to Rendering          Creating a Cache Page Output Dependency          Configuring Caching for an Entire Application

Lesson 1: Using Master Pages¶

Master Page¶

<%@ Master
    ...
%>

Content Page¶

<%@ Page 
    MasterPageFile="~/MyMasterPage.master" 
    ... 
%>
<!-- Option declaration needed if referencing public members of master page from content page -->
<%@ MasterType VirtualPath="~/MyMasterPage.master" %>

Programmatically Changing a Master Page¶

void Page_PreInit(object sender, EventArgs e)
{
    MasterPageFile = "~/MyMasterPage.master";
}

Lesson 2: Using Themes¶

Contents¶

• Skins — *.skin files
• Cascading Style Sheets — *.css files
• Images and other resources
  

Creation¶

• Each theme has its own subfolder under the ~/App_Themes folder.
• The name of the theme matches the subfolder name.
  

Application¶

• Page level — Done in the @Page directive
• Web.config level — Done via the <page Theme="ThemeName" > or <page StyleSheetTheme="ThemeName" > in the <system.web> section.
• Properties defined via StyleSheetTheme are applied before a page's control property set, and therefore can be overridden. By contrast, properties defined via Theme are applied after a page's control property set, and therefore cannot be overridden.
  

Creating a Skin¶

Types of Skins¶

• Default Skins — Has no SkinID attribute; automatically applies to all controls of the EXACT same type when a theme is applied to a page.
• Named Skins — Has a SkinID attribute; applied manually to each control via its SkinID attribute.
  

Restrictions¶

• Skin elements MUST contain the runat="server" attribute.
• Skin elements CANNOT contain the ID attribute.
  

Sample Skin Content¶

<!--===== Default Skin =====-->
<asp:Button runat="server"
    BackColor="Red"
    ForeColor="White"
    Font-Name="Arial"
    Font-Size="9px" 
    />

<!--===== Named Skin =====-->
<asp:Label runat="server"
    SkinId="Title"
    Font-Size="18px" 
    />

<!--===== Using Images in a Theme =====-->
<!-- Company A’s Skin File -->
<asp:Image runat="server" SkinID="CompanyLogo"
    ImageUrl="~/App_Themes/Contoso/contoso.jpg" 
    />

<!-- Company B’s Skin File -->
<asp:Image runat="server" SkinID="CompanyLogo"
    ImageUrl="~/App_Themes/Fabrikam/fabrikam.jpg" 
    />

The above image skin would be applied to the following image on a page. When the theme is change, the image would change too.

<asp:Image runat="server" SkinID="CompanyLogo" />

Precedence Rules for Applying Themes¶

Attributes and elements take precedence in the following order. (Each item takes precedence over preceding items.)

1. <page StyleSheetTheme="ThemeName" > elements in the <system.web> section of the web.config file.
2. StyleSheetTheme attributes in the @Page directive.
3. Local control attributes
4. <page Theme="ThemeName" > elements in the <system.web> section of the web.config file.
5. Theme attributes in the @Page directive.
   

Disabling a Theme¶

• For a page: <%@ Page EnableTheming="false" %>
• For a control: EnableTheming="false"
  

Applying a Theme Programmatically¶

Apply any of the following in the Page_PreInit event handler.

• Page.Theme
• Page.StyleSheetTheme
• uxControl.SkinID
  

Lesson 3: Caching¶

Application Caching¶

Overview¶

• Use the Cache object just like Session or similar objects: Cache["key"] = object;
• Cache items are application-wide: shared between users and requests
• Objects placed into the cache must be serializable
  

Inserting Items¶

Insert items via the Cache.Insert() method, which has overloads using the following parameters.

Parameter	Description
key	Unique name (String) identifying the cached object
value	The cached data (Object)
dependencies	A file or key to another item, which, when changed, triggers this item to be evicted. Can be a single item (CacheDependency object) or multiple items (AggregateCacheDependency object).
absoluteExpiration	A DateTime when the object should be evicted
slidingExpiration	Defines the maximum period of inactivity (TimeSpan) before the object is evicted.
priority	A CacheItemPriority indicating which objects are evicted when memory runs low. (Lower priority items are evicted sooner.) Can be Low, BelowNormal, Normal (default), AboveNormal, High, or NotRemovable
onRemoveCallback	An event handler that's called upon object eviction.

Page Output Caching¶

Declarative Configuration¶

Each page can be cached independently via the <%@ OutputCache %> directive, which has the following attributes.

Attribute	Description
Duration	The only required attribute. Number of seconds to cache the page
Location3	OutputCacheLocation enum: Any (default), Client, Downstream, Server, None, or ServerAndClient.
CacheProfile3	Name of the cache setting to associate with the page. Default="".
NoStore3	Boolean that determines whether sensitive data is saved in secondary storage.
Shared4	Boolean that determines whether user control output can be shared among multiple pages.
VaryByParam1	Semicolon-separated list of strings which correspond to parameter names (query string or POST parameters) by which the output cache should be versioned. Values include none or an asterisk (which varies by all parameters).
VaryByControl1	Semi-colon separated list of strings representing IDs of server controls in the user control.
SqlDependency2	String that identifies a set of database and table name pairs on which a page's output cache depends.
VaryByCustom	Any text representing custom caching. If this is a browser, cache is varied by browser and major version. If this is a custom string, you must override the GetVaryByCustomString method in Global.asax.
VaryByHeader	A semicolon-separated list of HTTP headers to version the output cache by.

¹ – Either VaryByParam or VaryByControl must be specified.
² – The SqlCacheDependency class monitors the database table so when items are update, they're removed from the cache when table-based polling is used. When SQL Server notifications are used with the value CommandNotification, a SqlDependency class is used to register for query notifications with the SQL Server instance.
³ – Cannot be used in a user control.
⁴ – Cannot be used in an ASP.NET page.

Partial-Page Caching¶

To cache a portion of a page, move that portion into a user control and use the <@ OutputCache > directive within it. Or you can use Substitution (see below).

Programmatic Caching¶

Programmatic caching is done via the Response.Cache object, which has the following methods.

• SetExpires — specifies the number of seconds the page is cached.
• SetCacheability — specifies HttpCacheability enum: Public (caching at both client and server) or Server (caching at server only).
• SetValidUntilExpires — pass a True to configure the cache to ignore cache-invalidation headers.
  

Using Substitution to Update Caches¶

• Response.WriteSubstitution method — You add static placeholders to your page, and then use the Response.WriteSubstitution method to specify a method (with an HttpResponseSubstitutionCallback signature) that replaces portions of a cached page with dynamically generated content.
• Substitution control — Similar to Label control, but exempt from output caching. The MethodName property specifies the method that generates the content, accepting an HttpContext parameter and returning a String containing the content.
  

Programmatically Invalidating Cached Pages¶

Determining Whether to Return a Cached Page Prior to Rendering¶

Creating a Cache Page Output Dependency¶

Configuring Caching for an Entire Application¶