.Net

1
.Net

• Table of contents
• Introduction to VS 2005
• Application and Page Frameworks
• GUI Controls
• Validation Server Controls
• Working with Master Pages
• Themes Skins
• Collections Lists
• Data Binding
• Data Management with ADO.Net
• Working with XML
• Site Navigation
• Security
• State Management
• Caching
• Debugging Error Handling
• File I/O Streams
• Configurations

2
Working with Master Pages

• All web application will have a master page or a
  home page
• If we hit a website the default page that comes
  is the home page
• It will have the name index.html or default.aspx
  or home.html or some thing like that.
• From this master page, we navigate to the rest of
  the pages through buttons or links
• To set a page as the master page all we need to
  do is, just right click on the aspx page in the
  solution explorer and select Set as Start Page
  from the pop up menu.

3
Themes and Skins

• Themes and Skins provide a good look and feel to
  our site or web application.
• We can set the theme using CSS (Cascading Style
  Sheet)
• In the ltHEADgt portion of our aspx page if we give
  ltlink hrefcss path typetext/css
  relstylesheetgt then the particular style
  specified in the CSS will be used for the page

4
Themes and Skins

• We can also allow the user to change the skin
  (color of controls on the application) and
  dynamically deliver the theme and skin on his
  browser.
• This is achieved using session variables.
• Once the user selects a skin,the value is stored
  in a session variable and it will be used for the
  session.

5
Themes and Skins

• If the user want the same skin to be applied
  whenever he logs in, there are two ways to
  achieve that.
• Cookies The information will be stored on the
  clients system and will be taken when he logs in
  from the system again. But this will work only in
  a particular system
• To make this global, the information need to be
  stored on the server, in a table against the user
  name.

6
Namespaces

• Compilation units that let you organize and reuse
  code
• No relationship between namespaces and file
  structure (unlike Java)
• Namespaces provide a way to uniquely identify a
  type
• Provides logical organization of types
• Namespaces can span over assemblies
• Namespaces can be nested
• The fully qualified name of a type includes all
  namespaces

7
Namespaces

• The fully qualified name of a type includes all
  namespaces
• Namespaces are mainly used to distinguish between
  the objects having same names
• With-in a namespace, the names of all the objects
  should be unique
• namespace N1 // is referred to as N1
• class C1    // is referred to as N1.C1
• class C2  // is referred to as N1.C1.C2
•    //End of N1.C1.C2
• //End of N1.C1
• namespace N2   // is referred to as N1.N2
• class C2 // is referred to as N1.N2.C2    
• // End of N1.N2.C2
• //End of N1.N2
• //End of N1

8
Collections

• A collection is a specialized class that
  organizes and exposes a group of objects
• Various collection classes are ArrayList,
  SortedList, BitArray, HashTable, Queue and Stack
• They are all included in System.Collections
  namespace
• Like arrays, members of collections can be
  accessed by an index
• Unlike arrays, collections can be resized
  dynamically

9
ArrayList

• Arraylist allows to dynamically add and remove
  items from a simple list
• Array List is a zero based collection
• The items in the list are retrieved by accessing
  the item index
• Methods
• Add()
• Remove()
• RemoveAt()
• Count()
• Property
• Capacity

10
SortedList

• Stores elements in the collection as a key-value
  pair that are sorted by the keys
• The elements in the SortedList can be accessed by
  key as well as by index
• A key cannot be a null reference whereas a value
  can be a null reference
• Any time when an element is added or removed from
  the collection, the indexes are adjusted to keep
  the list in the sorted order. Hence such
  operations are slower in this collection
• Methods
• Add()
• Remove()
• RemoveAt()
• Count()
• Property
• Count, Capacity, Item, Keys, Values

11
Data Binding

• Bounding values to the controls
• ltltControlgtgt.DataBind() method binds values for
  the control
• Page.DataBind() binds all the controls on the
  page
• Types
• Single value data binding
• Multi value data binding

12
Single Value Data Binding

• Applicable for server controls that displays one
  data at a time
• Controls like
• Textbox
• Label

13
Multi Value Data Binding

• Involves binding server controls to ArrayList or
  SortedList or any collection object
• Example
• Populating a drop down list with a collection
  object or a data set
• Populating a Data grid with a data set

14
Data Management with ADO.Net

• ADO ActiveX Data Objects
• Namespace
• System.Data
• Types
• Odbc For working with MySQL etc
• OleDb For working with OLEDB (Excel etc)
• Sql For working with MS SQL data bases
• Oracle For working with Oracle databases

15
Data Management

• Classes used (for Sql)
• Connection - SqlConnection
• Command - SqlCommand
• DataReader - SqlDataReader
• DataAdapter SqlDataAdapter
• For other database types, we need to put the
  appropriate prefix.(like OdbcConnection and so on)

16
Connection

• OdbcConnection con new OdbcConnection(Connection
  string)
• Connection string has details about which
  database is to be used and what is the user name
  and password are.
• Example
• DriverMySQL ODBC 3.51 DriverSERVERlocalhost
  DATABASEtest passwordsauser idroot

17
Connection Methods

• Open Opens a connection
• Close Closes a connection
• It is recommended to open a connection only if it
  is needed and close it when it is no longer
  needed. This would avoid wastage of system
  resources

18
Command

• OdbcCommand cmd new OdbcCommand(Query, con)
• Query SQL query like select from table1
• con is the connection object created
• Command object property
• CommandType This can be text or stored
  procedure or table

19
DataReader

• OdbcDataReader dr new OdbcDataReader()
• Usage - dr.Method
• DataReader Methods
• ExecuteReader For reading one or more rows (for
  select from)
• ExecuteScalar For reading a scalar value like
  select count() from
• ExecuteNonQuery for inserting or updating or
  deleting or executing a stored procedure or
  function

20
DataAdapter

• This is for filling data from more than one
  tables
• The data get filled into a DataSet
• OdbcDataAdapter da new OdbcDataAdapter(cmd)
• cmd command object created using the connection
  and SQL statement
• This will fetch the result of the command and
  stores it in the adapter

21
DataAdapter

• To put the data in a dataset, use the Fill method
• da.Fill(ds) DataSet ds new DataSet()
• We can also have DataTable or DataRow or DataView
  instead of DataSet
• Data adapter automatically opens and closes a
  connection. No need of having explicit open and
  close of a connection.

22
Working with XML

• XML eXtensible Markup Language
• Uses
• XML can be used to Store Data
• XML is used to create configuration files for
  different applications
• XML is used to Exchange Data in cross-platform
  applications
• Used in Web applications

23
Opening an XML

• System.Xml namespace is required
• Opening from an URL
• XmlDocument myDoc new XmlDocument()
• myDoc.Load ("http//localhost/sample.xml")
• Opening from a location in the local system
• XmlDocument myDoc new XmlDocument()
• FileStream myFile new FileStream("myDoc.xml",Fil
  eMode.Open)
• myDoc.Load(myFile)
• myFile.Close()

24
Reading the XML document

• XmlElement Class for accessing individual
  elements in a xml file
• Attributes, FirstChild, LastChild, InnerText,
  InnerXml, Name
• XmlAttribute Class for accessing attributes of
  the individual xml elements
• Name
• Value

25
Example

• To get the name and values of attributes in a xml
  file
• / Get the Attribute Collection /
• XmlAttributeCollection attrs
  myElement.Attributes
• / Get the number of Attributes /
• int aCount attrs.Count
• for (i0 ilt aCount i)
• Console.WriteLine (attrsi.Name)
• Console.WriteLine (attrsi.Value)

26
Writing XML

• Create XML Document object
• XmlDocument myDoc new XmlDocument()
• Load the root element
• myDoc.LoadXml ("ltwebinargtlt/webinargt")
• Create an element and add it to the parent
  element
• XmlElement myChildEle myDoc.CreateElement(Topi
  c")
• myChildEle.InnerText Dot Net"
  ParentElement.AppendChild (myChildEle)

27
Writing XML

• Create an attribute
• XmlAttribute myAttribute myDoc.CreateAttribute
  (Trainer")
• myAttribute.Value Softsmith"
• Add it to Parent element
• ParentElement.SetAttributeNode (myAttribute)
• XML file will be
• ltwebinargt
• ltTopic TrainerSoftsmithgtDot Netlt/Topicgt
• lt/webinargt

28
XmlReader and XmlWriter

• XmlReader To read an XML file
• XmlWriter To write Xml to a file (creating xml)
• XmlReader
• string filename_at_"books.xml"
• XmlTextReader bookXmlReader new XmlTextReader
  (filename)
• XmlWriter
• string fileName _at_"booksnew.xml"
• XmlTextWriter bookXmlWriter new
  XmlTextWriter(fileName,null)

29
XmlReader Example

• public void ReadDocument (XmlReader xmlR)
• try
• // read (pull) the next node in document order
• while (xmlR.Read())
• // print the current node's name type
• Console.WriteLine(xmlR.NodeType " "
  xmlR.Name)
• catch(XmlException e)
• Console.WriteLine ("Error " e.Message)

30
XmlWriter Example

• public void WriteDocument(XmlWriter writer)
• writer.WriteStartDocument()
• writer.WriteStartElement ("Person")
• writer.WriteAttributeString ("Gender", "Male")
• writer.WriteAttributeString ("Name", "Abc")
• writer.WriteElementString ("Phone",
  "111-222-3333")
• writer.WriteElementString ("Phone",
  "111-222-4444")
• writer.WriteEndElement()
• writer.WriteEndDocument()
• writer.Close()
• Output
• lt?xml version1.0?gt
• ltPersongt
• ltPhonegt111-222-3333lt/Phonegt
• ltPhonegt111-222-4444lt/Phonegt
• lt/Persongt