ListView control Improvements

ListView control is new databound control that is released in ASP.Net 3.5. To display data, we need to define 2 mandatory templates, LayoutTemplate and ItemTemplate. In ASP.Net 4.0 version, the LayoutTemplate is made optional and only defining ItemTemplate will display the data.

<asp:ListView ID="ListView1" runat="server"

        DataSourceID="SqlDataSource1" ClientIDMode="Predictable" ClientIDRowSuffix="EmpNo,EmpName">

        <ItemTemplate>

            <span style="background-color: #DCDCDC;color: #000000;">EmpNo:

            <asp:Label ID="EmpNoLabel" runat="server" Text='<%# Eval("EmpNo") %>' />

            <br />

            EmpName:

            <asp:Label ID="EmpNameLabel" runat="server" Text='<%# Eval("EmpName") %>' />

            <br />

            Address:

            <asp:Label ID="AddressLabel" runat="server" Text='<%# Eval("Address") %>' />

            <br />

            City:

            <asp:Label ID="CityLabel" runat="server" Text='<%# Eval("City") %>' />

            <br />

            Country:

            <asp:Label ID="CountryLabel" runat="server" Text='<%# Eval("Country") %>' />

            <br />

            <br />

           </span>

        </ItemTemplate>     

    </asp:ListView>

    <asp:SqlDataSource ID="SqlDataSource1" runat="server"

        ConnectionString="<%$ ConnectionStrings:ConnectionString %>"

        SelectCommand="SELECT * FROM [Employees]"></asp:SqlDataSource>

Empty Website project and Cleaner Web.Config file

Visual Studio 2010 includes a new project template to create empty ASP.Net 4.0 Web application project (Similar to Empty Website Template in older version).  These empty project templates will now include Web.Config file which is very clean and simple. Due to so many new additional features released, the web.config file is overloaded with information on handlers and modules (for asp.net ajax, etc). To maintain the Web.config easily, Visual Studio 2010 (from beta 2) includes only entries to identify the target framework used. Rest of the needed settings are moved to machine.config file.

Read more about this feature on Scott’s blog.

Routing in Webforms

Routing is a technique where asp.net webforms can be accessed with a friendly and descriptive URL’s.  Hence, the ugly URL’s with querystring can now be converted to a meaningful and descriptive which will be easy to remember and will improve the search engine rank.

Read Rangan’s post on routing here.

CSS Improvements

The other major improvements in ASP.Net 4.0 are on the way the HTML rendered to the client browser. The rendered HTML will be complaint with latest HTML standards.

Few things will be,

1.      A new property called controlRenderingCompatibilityVersion is added to the Pages element of configuration files.

<pages controlRenderingCompatibilityVersion="3.5|4.0"/>

The value “3.5” indicates the controls are rendered in legacy ways. The value “4.0” indicates the control will be rendered with the latest improvements of 4.0 framework.

2.      Till 3.5 framework, setting “Enabled=false” for any control will render disabled attributes in the HTML for the control. According to the latest HTML standard the disabled attribute should be set only for INPUT tags. ASP.Net 4.0 addresses this issue by rendering disabled attribute to only INPUT tags and a CSS class called “aspNetDisabled” to other controls to disable it when controlRenderingCompatibilityVersion property is set to “4.0”.

Below you can find a HTML rendered for a Label and TextBox control when controlRenderingCompatibilityVersion property is set to “4.0”.

<span id="Label1" class="aspNetDisabled">Label</span>

<input name="TextBox1" type="text" id="TextBox1" disabled="disabled" />

3.      From ASP.Net 2.0, the hidden fields generated for viewstate are packed inside a div tag for XHTML standard. This leads a small white space on the page. ASP.Net 4.0 now includes this div with a css class “aspNetHidden”. We can now define the class to prevent the white space by setting border to 0.

<div class="aspNetHidden">...</div>

4.      Menu controls render markup that is semantically correct and compliant with accessibility guidelines.

5.      Validation controls do not render inline styles.

RabioButtonList and CheckboxList Changes

From ASP.Net 4.0, the RadioButtonList and CheckBoxList controls includes 2 more value fro the property RepeatLayout.

1.      OrderedList

The radiobutton/checkbox is rendered as li elements within an ol element.

2.      UnorderedList

The radiobutton/checkbox is rendered as li elements within an ul element.

Improvements in Code Expressions

There is a new code expression syntax that is being shipped with ASP.Net 4.0.  We commonly use the following syntax to output a value from aspx page called code expression.

<%= HTMLOutput %>

There is a new code expression releasing with ASP.Net 4.0 version that will html encode the value.

<%: HTMLOutput %>

The above code expression will output the value after doing html encode. i.e. the above expression is equivalent to

<%= HttpUtility.HtmlEncode(HTMLOutput) %>

Permanent Redirection with HTTP 301 Moved Permanently Response

When we move our internet page to a different location, it is always required to send “HTTP 301 Moved Permanently” response to the search engines to hold back the page rank before redirecting to the new page. Understanding this need asp.net 4.0 includes a new method to do redirection called RedirectPermanent().

Refer below,

Response.RedirectPermanent("new url")