Let’s Web developer has to develop a page where the user submits a file containing the ISBN of all the books he/she needs information about. The user has to retrieve these books and create an XML file with the book title, author and price.
Web developer can use a LINQ query to pass child elements and nest data, by …
In .NET Framework 4.0 the System.Xml APIs are obsolete and are maintained for compatibility reasons only. Web developers can create XML file by using LINQ to XML. The next picture presents classes in LINQ to XML.
The classes in LINQ to XML
These classes are included in System.Xml.Linq namespace and the following ones are the most …
Software developer can interact with session state using the System.Web.SessionState.HttpSessionState class, which is provided in an ASP.NET web page as the built-in Session object. Items can be added to the collection and retrieved after in the same manner as items can be added to a page’s view state:
For example, software developer might store a …
How to transfer information between pages in ASP.NET using a query string in VB.NET.
Software developer can use this approach for information that don’t need to be hidden or made tamper-prof. Unlike view state information passed through the query string is clearly visible and unencrypted. The query string is the portion of the URL after the question mark in the following example:
https://www.google.com?q=look+for+aspnet+code
Software developer can store information in the query string himself using …
How to transfer information between pages in ASP.NET using cross-page posting in VB.NET
Software developer can transfer information between pages with technique named cross-page posting. If he wants to do use it he has to define specific, limited methods that extract just the information he need it. Let’s for example he have a page with text boxes as controls for credit card. In this case software developer might decide to add …
Software developer can store custom objects in a view state just as easily as regular types. However, to store an item in a view state, ASP.NET must be able to convert it into a stream of bytes. This process is called serialization. If developer’s objects aren’t serializable, he will receive an error message when he attempts to place …
You can put the focus on the following types of ASP.NET controls: Button, LinkButton, and ImageButton controls, CheckBox control, DropDownList control, FileUpload control, HyperLink control, ListBox control, RadioButton control, TextBox control.
The following VB.NET code example shows how to set the focus on the control with the ID TextBox1:
Protected Sub Page_Load(ByVal sender As Object, _ ByVal e As System.EventArgs) …
How to preserve member variables for an ASP.NET page in VB.NET
Software developers can follow the next basic principle. They can save all member variables to view state when the Page.PreRender event occurs and retrieve them when the Page.Load event occurs. The Page.Load event happens every time the page is created. In case of a postback, the Load event occurs first, followed by any other control events. The next …
You as software developer can use code to add information directly to the view state collection of the containing page and recover it later after the page is posted back. The type of information you can store includes not only the simple data types, but your custom objects too. The view state collection is provided by ViewState property …
To get the current date in VB.NET you should use DateTime.Now Property:
‘ Get the current date and time in VB.NET
Dim currentDate As DateTime …