What is the ASP.NET Page Lifecycle?
- I: Initialize
- L: Load ViewState
- L: Load PostBack Data
- L: Load
- R: Raise PostBack Event
- S: Save ViewState
- R: Render
Name some Server-Side State Management.
- 1- Application Object
- 2- Session Object
- 3- Database
- 4- Profile properties
Name some Client-Side State Management.
- 1- Cookies
- 2- Hidden Field
- 3- ViewState
- 4- Querystring
- 5- Control State
What are the 3 parts of an ASP.NET web form?
- 1- The Page Directive: Provides information about the webform page.
- 2- The Doctype: Indicates the type of markup being used (i.e. HTML or XHTML)
- 3- The Body: or <html> tag.
What are some characteristics of Web Form Pages?
- They are HTTP-based and stateless.
- The don't know whether the requests are all from the same client.
- Pages are created & destroyed with each trip to the server therefore the information will be lost.
- There are two ways to manage a web page's state. 1- Client-side, 2- Server-side.
What are Windows Services?
- A long-running executable that performs specific functions and which is designed not to require user interaction.
- It can be configured to start with Windows.
- It Runs in the background.
- It appears in the processes list in the Task Manager.
What is ViewState?
- It is used to store small amounts of information for a page that will post back to itself.
- It does provide semi-secure functionality.
- It has automatic retention of page and control state, which means you don't need to do anything about getting the data of the controls back after posting page to server.
- Values that are stored are invisible during "View Source".
- Each control on a web form - including the page itself - has a ViewState property.
What are Cookies?
- They are used when you need to store small amounts of info on the client.
- Security must NOT be an issue.
- Mainly used for tracking data settings.
What are Namespaces?
They uniquely identify particular class binaries or code.
What are Web Services?
- It is a software system designed to support interoperable machine-to-machine interaction over a network.
- Frequently just Web API's that can be accessed over a network system hosting the service.
- The software component is described via WSDL and can be accessed by using SOAP over HTTP.
- A Method exposed as a Web Service has the [WebMethod] attribute.
What is a Session-state Object?
- It is used to store short-lived information that is specific to an individual session.
- It is secure
- Do NOT use large amounts of data to store here.
- This object is crated & maintained for the lifetime of every session in you app.
- It can use significant server resources and can affect scalability.
What is Session State?
- The data that an application caches and retrieves accross different requests.
- Session represents all the requests sent by a user for the duration of a connection to the site.
- The collection of persistant data that the user generated and used during the session.
- Has no correspondance to any logical entities that make up the HTTP protocol & specifications.
What is a Querystring?
- It is used to transfer small amount of information from one page to another.
- It is NOT secure.
- You can only use it if you are requesting the same page, or another page via a link.
- There is a 255 character limit.
- You must use the HTTP Get method to post the web page.
- It indicates blocks of data stored somewhere on a server.
- Name placeholder: indicates the key to retrieve info.
- Value placeholder: the content stored in the session state.
- Session ID: where name/value pairs are grouped.
What is SOAP?
- Simple Object Access Protocol
- It is a way for a program runnin in one kind of OS to communicate with a program in the same or another kind of OS such as Windows to Linux by using the HTTP protocol and XML.
What is XML?
- Extensibel Markup Language
- All XML documents must have a root "parent" element.
- All XML elements must have a closing tag.
- XML declaration on the top of the XML doc. is not part of the XML doc so it doesn't need a closing tag.
- XML elements are case-sensitive.
- XML elements must be properly nested.
- XML attribute values must be in quotes.
- White-space is NOT truncated.
What is WSDL?
- Web Services Description Language.
- It is an XML-based language that provides a model for describing web services.
- A client program connecting to a web service can read the WSDL to determine what functions are available on the server.
XML naming rules.
- Names can contain letters, numbers, and other characters.
- Names must NOT start with a number or a punctuation character.
- It is used to store small amount of information for a page that will post back to itself or another page.
- NOT very secure. The value is not hidden
- Can be used only on pages that are submitted to the server.
- Values can be seen during "View Source".
Database [Web Forms Data]
- Used to store large amount of information.
- For managing trasactions or information that must survive application and session restarts.
- Data mining is a concern.
- It is the MOST secure way of retaining information.
What are 2 primary parts of ADO.NET?
- 1- Data provider
- 2- Datasets.
What is a Data Provider?
- Classes that provide access to a data source, such as SQL server or Oracle.
- Each data source has its own set of provider objects, but each have a common set of utility classes.
What is ADO.NET?
- A set of computer software components that can be used by programmers to access data and dataservices.
- It is part of the class library for the .NET Framework.
- It is considered to be an evolution of ActiveX Data Object (ADO).
LINQ: What are the steps to get info from Datasets?
- 1- Define an enumerable collection that you want to query (Dim query = From Prod in Products
- 2- A Filter expression that specifies the items that you want. (Where (Prod.Price > 50)
- 3- Conditions for grouping or ordering (Order By Prod.Price ascending)
- 4- The type of object that you want to obtain from the query (Select Prod).
What is LINQ?
- Language Integrated Query
- Allows access to in-memory objects, such as Datasets and XML along with SQL.
LINQ: Steps to get info from Entity Class.
- 1- Specify the database connection by using a DataContext object (Dim db as New DataContext(ConnectionString)
- 2- Declare a typed Table object to hold the query results. (Dim custTable as Table(of Customer)=db.GetTable(of Customer) ())
- 3- Define a LINQ query. (Dim query=From Cust In custTable Select cust).
- 4- Execute the LINQ query. (For Each c in query (write info to console) Next).
- -from, in, where, select.
- -ascending, descending.
LINQ: Modify Data.
- User the SubmitChanges method on the DataContext object to submit the changes to the database.
- The changes are held in memory until you invoke the SubmitChanges method.
ADO.NET: Data Provider Utility Classes.
- 1- Connection: Used to communicate with data source.
- 2- Command: Used to perform some action.
- 3- Parameter: A single parameter to a command.
- 4- DataAdapter: A bridge used to transfer data between a data source and a dataset object.
- 5- DataReader: Used to process a large list of results one record at a time, read-only, forward-only.
What is a postback, what is a callback, and how
do they differ?
The ability of client side code to call the server side code is called callback. When an action is taken on an interactive web page and then the entire page and the contents of that page are sent back to the server it is called Postback.