ENTITY FRAMEWORK LESSION 1.

Microsoft entity framework is ORM (object relation mapping) that enables developer to work

with relational database and domain sepecific objects.It skips the code that we was writing in earlier times to get data from database. Now developers issues queries using LINQ, then retrieve and manipulate the data as strongly typed objects.ORM implementation provides services like: change tracking, identity resolution, lazy loading and query translation. Now developers only need to focus on business logic rather than fetching data from database.

It is an enhancement to ADO.NET that gives developers an automated mechanism for accessing & storing the data in database and working with the results in addition to DataReader and DataSet.

O/RM includes three main parts: Domain class objects, Relational database objects and Mapping information on how domain objects maps to relational database objects (tables, views & storedprocedures). ORM helps us to keep our database design separate from our domain class design. This makes application maintainable and extendable. It also automates standard CRUD operation (Create, Read, Update & Delete) so developer doesn’t need to write it manually.

here are many ORM frameworks for .net in the market like DataObjects.Net, NHibernate, OpenAccess, SubSonic etc . ADO.NET Entity Framework is from Microsoft.

Differences between entiry framework and LINQ to sql

1.Entity framework supports not only SQL Server but also other database like Oracle, DB2, MySQL etc.

2.Most of the time L2S classes must be one-to-one with database objects e.g. Customer class can be mapped only with Customer table. On other hand in Entity Framework we can map domain class with multiple tables using various inheritance strategies like table per type (class) or table per hierarchy of classes etc.

3. We can also follow mutliple techniques using entity framework like code first, model first or database first. Now no  longer dependencies on old techniques.

4. In upcoming products microsoft also giving support and integration of entity framework.

ENTITY FRAMEWORK ARCHITECHTURE (GOT FROM A ANOTHER WEBSITE IT IS NOT MINE):

Following figure shows the overall architecture of the Entity Framework. Let’s see each component of the architecture:

EDM (Entity Data Model): EDM consist three main parts- Conceptual model, Mapping and Storage model.  

Conceptual Model: Conceptual model is our model classes and their relationships. This will be independent from our database table design. 

Storage Model: Storage model is our database design model which includes tables, views, stored procedures and their relationships and keys. 

Mapping: Mapping consist information about how our conceptual model is mapped to storage model. 

LINQ to Entities:LINQ to Entities is query language used to write queries against the object model. It returns entities which are defined in the conceptual model. We can use your LINQ skills here.

Entity SQL: Entity SQL is again a query language same as LINQ to Entities. However it is little more difficult than L2E and also developer need to learn it separately. 

Object Service: Object service is a main entry point for accessing data from database and to return it back. Object service is responsible for materialization which is process of converting data returned from entity client data provider (next layer) to an entity object structure.  

Entity Client Data Provider: The main responsibility of this layer is to convert L2E or Entity SQL queries into SQL query which is understood by underlying database. It communicates with ADO.Net data provider which in turn sends or retrieves data from database.

ADO.Net Data Provider: This layer communicates with database using standard ADO.Net.

I'll do more posting on this topic very soon, because entity framework 4.5 is knocking the door. :)

ASP.NET 4.5 Web Pages 2

New features include the following:

   1. New and updated site templates.
   2. Adding server-side and client-side validation using the Validation helper.
   3. The ability to register scripts using an assets manager.
   4. Enabling logins from Facebook and other sites using OAuth and OpenID.
   5. Adding maps using the Maps helper.
   6. Running Web Pages applications side-by-side.
   7. Rendering pages for mobile devices.

   8. The configuration logic For MVC applications has been moved from Global.asax.cs to a set of static classes in the App_Start directory. Routes are     registered in RouteConfig.cs. Global MVC filters are registered in FilterConfig.cs. Bundling and minification configuration now lives in     BundleConfig.cs
  9. Publishing of the project come under the project from solution explorere, It is removed from the top menu. Now whole setting can be done by right     click on the project and set the publish settings.

 When you open a Visual Studio 2010 SP1 Web project for the first time in Visual Studio 11 Beta, the following properties are added to the project file:

    FileUpgradeFlags
    UpgradeBackupLocation
    OldToolsVersion
    VisualStudioVersion
    VSToolsPath
FileUpgradeFlags, UpgradeBackupLocation, and OldToolsVersion are used by the process that upgrades the project file. They have no impact on working with the project in Visual Studio 2010.

VisualStudioVersion is a new property used by MSBuild 4.5 that indicates the version of Visual Studio for the current project. Because this property didn’t exist in MSBuild 4.0 (the version of MSBuild that Visual Studio 2010 SP1 uses), we inject a default value into the project file.

Extract to user control

In large web pages, it can be a good idea to move individual pieces into user controls. This form of refactoring can help increase the readability of the page and can simplify the page structure. This is similiar to "Extract to metho" functionality which is available in 3.5 onwards. So "Extract to User Control" is available in .net 4.5.


The VSToolsPath property is used to determine the correct .targets file to import from the path represented by the MSBuildExtensionsPath32 setting.

There are also some changes related to Import elements. These changes are required in order to support compatibility between both versions of Visual Studio.

Configuration Changes in ASP.NET 4.5 Website Templates

The following changes have been made to the default Web.config file for site that are created using website templates in Visual Studio 2012 Release Candidate:

    In the <httpRuntime> element, the encoderType attribute is now set by default to use the AntiXSS types that were added to ASP.NET. For details, see AntiXSS Library.

    Also in the element, the requestValidationMode attribute is set to "4.5". This means that by default, request validation is configured to use deferred ("lazy") validation. For details, see New ASP.NET Request Validation Features.

    The <modules> element of the section does not contain a runAllManagedModulesForAllRequests attribute. (Its default value is false.) This means that if you are using a version of IIS 7 that has not been updated to SP1, you might have issues with routing in a new site. For more information, see Native Support in IIS 7 for ASP.NET Routing.

Changes in webforms 4.5

ASP.NET Web Forms Changes:

Strongly Typed Data Controls

In ASP.NET 4.5, Web Forms includes some improvements for working with data. The first improvement is strongly typed data controls. For Web Forms controls in previous versions of ASP.NET, we display a data-bound value using Eval and a data-binding expression:
eg: <asp:Repeater runat="server" ID="customers">
        <ItemTemplate>
            <li>
                First Name: <%# Eval("FirstName")%>

                Last Name: <%# Eval("LastName")%>

            </li>
        </ItemTemplate>
    </asp:Repeater>

For two-way data binding, we use Bind:
<asp:FormView runat="server" ID="editCustomer">
    <EditItemTemplate>
        <div>
            <asp:Label runat="server" AssociatedControlID="firstName">
                First Name:

            <asp:TextBox ID="firstName" runat="server"
                Text='<%#Bind("FirstName") %>' />
        </div>
<EditItemTemplate>
<asp:FormView>
        <div>
            <asp:Label runat="server" AssociatedControlID="lastName">
                First Name:</asp:Label>
            <asp:TextBox ID="lastName" runat="server">

                Text='<%#BindItem.LastName %>' />

At run time, these calls use reflection to read the value of the specified member and then display the result in the markup. This approach makes it easy to data bind against arbitrary, unshaped data.

To address this issue, ASP.NET 4.5 adds the ability to declare the data type of the data that a control is bound to. We do this using the new ItemType property. When we set this property, two new typed variables are available in the scope of data-binding expressions: Item and BindItem. Because the variables are strongly typed, we get the full benefits of the Visual Studio development experience.

The following example shows for the Item member:

<asp:Repeater runat="server" ID="customer" ModelType="WebApplication.Customer">
<itemTemplate>
    First Name: <%# Item.FirstName %><br/>
    Last Name: <%# Item.LastName %>
</itemTemplate>
</asp:Repeater>

For two way binding "BindItem" can be used in place of Item.

Model Binding

Model binding extends data binding in ASP.NET Web Forms controls to work with code-focused data access. It incorporates concepts from the
ObjectDataSource control and from model binding in ASP.NET MVC.
To configure a data control to use model binding to select data, you set the control's SelectMethod property to the name of a method in the page's code. The data control calls the method at the appropriate time in the page life cycle and automatically binds the returned data. There's no need to explicitly call the DataBind method.

In the following example, the GridView control is configured to use a method named GetCategories:

<asp:GridView ID="categoriesGrid" runat="server" ItemType="WebApplication1.Model.Category"
    SelectMethod="GetCategories" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="CategoryID" HeaderText="ID" />
        <asp:BoundField DataField="CategoryName" HeaderText="Name" />
        <asp:BoundField DataField="Description" HeaderText="Description" />
        <asp:TemplateField HeaderText="# of Products">
            <ItemTemplate><%# Item.Products.Count %></ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Here  we have created "GetCategories" method in code behind file which is without any parameters and returning an IEnumerable or IQueryable object. If the new ItemType property is set (which enables strongly typed data-binding expressions, as explained under Strongly Typed Data Controls earlier), the generic versions of these interfaces should be returned — IEnumerable or IQueryable, with the T parameter matching the type of the ItemType property (for example, IQueryable).

Code behind method defination of "GetCategories":
public IQueryable
GetCategories()
{
    var db = new Northwind();
    return db.Categories.Include(c => c.Products);
 }

Any query can be placed on returned IEnumerable and IQueryable objects eg. sorting, paging etc.

Filtering by values from a control

Suppose we want to extend the example to let the user choose a filter value from a drop-down list. Add the following drop-down list to the markup and configure it to get its data from another method using the SelectMethod property:

<asp:Label runat="server" AssociatedControlID="categories"
    Text="Select a category to show products for: " />
<asp:DropDownList runat="server" ID="categories"
    SelectMethod="GetCategories" AppendDataBoundItems="true"
    DataTextField="CategoryName" DataValueField="CategoryID"
    AutoPostBack="true">
  <asp:ListItem Value="" Text="- all -" />
</asp:DropDownList>

<asp:GridView ID="productsGrid" runat="server" DataKeyNames="ProductID"
    AllowPaging="true" AllowSorting="true" AutoGenerateColumns="false"
    SelectMethod="GetProducts" >
    <Columns>
        <asp:BoundField DataField="ProductID" HeaderText="ID" />
        <asp:BoundField DataField="ProductName" HeaderText="Name"                  
             SortExpression="ProductName" />
        <asp:BoundField DataField="UnitPrice" HeaderText="Unit Price"
             SortExpression="UnitPrice" />
        <asp:BoundField DataField="UnitsInStock" HeaderText="# in Stock"
             SortExpression="UnitsInStock" />
    </Columns>
    <EmptyDataTemplate>
         No products matching the filter criteria were found
</asp:GridView>

In the page code, add the new select method for the drop-down list:

public IQueryable<Category>
GetCategories()
{
    return _db.Categories;
 }

Finally, update the GetProducts select method to take a new parameter that contains the ID of the selected category from the drop-down list:

public IQueryableGetProducts([QueryString("q")] string keyword,[Control("categories")] int? categoryId)
 {
    IQueryable query = _db.Products;
 
    if (!String.IsNullOrWhiteSpace(keyword))
    {
        query = query.Where(p => p.ProductName.Contains(keyword));
    }
    if (categoryId.HasValue && categoryId > 0)
    {
        query = query.Where(p => p.CategoryID == categoryId);
    }
    return query;
 }

Now when the page runs, users can select a category from the drop-down list, and the GridView control is automatically re-bound to show the filtered data. This is possible because model binding tracks the values of parameters for select methods and detects whether any parameter value has changed after a postback. If so, model binding forces the associated data control to re-bind to the data.

HTML Encoded Data-Binding Expressions

we can now HTML-encode the result of data-binding expressions. Add a colon (:) to the end of the <%# prefix that marks the data-binding expression:

<asp:TemplateField HeaderText="Name">
    <ItemTemplate><%#: Item.Products.Name %></ItemTemplate>
</asp:TemplateField>

Unobtrusive Validation

We can now configure the built-in validator controls to use unobtrusive JavaScript for client-side validation logic. This significantly reduces the amount of JavaScript rendered inline in the page markup and reduces the overall page size. Wecan configure unobtrusive JavaScript for validator controls in any of these ways:
Globally by adding the following setting to the element in the Web.config file:

<add name="ValidationSettings:UnobtrusiveValidationMode" value="WebForms" />

HTML5 Updates

Some improvements have been made to Web Forms server controls to take advantage of new features of HTML5:

    The TextMode property of the TextBox control has been updated to support the new HTML5 input types like email, datetime, and so on.
    The FileUpload control now supports multiple file uploads from browsers that support this HTML5 feature.
    Validator controls now support validating HTML5 input elements.
    New HTML5 elements that have attributes that represent a URL now support runat="server". As a result, we can use ASP.NET conventions in URL paths, like the ~ operator to represent the application root
 (for example, <video runat="server" src="~/myVideo.wmv" />).
    The UpdatePanel control has been fixed to support posting HTML5 input fields.
                Text='<%# Bind("LastName") %>' />
        </div>
        <asp:Button runat="server" CommandName="Update"/>
    </EditItemTemplate>
</asp:FormView>