Neal Stublen

How does XMLReader work?  XmlReader.Read() Advances to next node XmlReader properties access node name, value, attributes, etc. Returns false if there are no additional nodes

Reading XML Files XmlReader r = XmlReader.Create(path, settings); r.ReadToDescendant(nodeName); do { r.ReadStartElement(nodeName); r.ReadElementContentAsString(); } while (r.ReadToNextSibling(nodeName)); r.Close();

Code Practice  Create a new project called CustomerImport  Import Customers into a List<> from any.xml file  Fill a TreeView with the Customer data

Review  TreeView  XmlReader

var Data Type  We can declare a variable as type “var” instead of using a specific data type The compiler assigns an implicit data type at compile-time (not run-time) var value = 0; var array = new string[10]; var list = new List (); var str = "Hello"; // str is string type str = 6; // can’t assign int

What’s LINQ?  SQL-like query expression on any enumerable object type int[] numbers = new int[100]; for (int index = 0; index < 100; ++index) { numbers[index] = index; } var odds = from number in numbers where number % 2 != 0 select number;

Try it in LINQPad  Duplicate code from previous slide  Filter out prime numbers from array using LINQ query

LINQ Expressions from [type] element in collection join element2 in collection2 on key1 equals key2 where condition // any boolean expression orderby expression [ascending|descending] select columnExpression select new [type] { name=value, name=value }

LINQ Expressions from cust in customers join invoice in invoices on cust.CustomerID equals invoice.CustomerID where invoice.InvoiceDate < sixtyDaysAgo orderby invoice.InvoiceTotal descending select

Try it with CustomerImport  Create a List object by looping through SqlDataReader  Perform LINQ queries on List

LINQ-to-SQL  Create objects that represent database entities  Use the same LINQ query expressions against a database  Just restricts “where” clause to SQL- compatible operations

See It In Action

LINQ on Database Objects  Add LINQ data objects to a project  Drop tables from Server Explorer  Use the new DB to query the database using LINQ  Insert, Update, Delete objects, db.SubmitChanges()  Add related items, db.SubmitChanges()  Paging: (from…).Skip(5).Take(5)

LINQ’d Customer-Invoice List  Using LINQ objects, fill a list view with all invoices sorted by CustomerName

ToolTips and HelpProviders  Add ToolTip control  Set ToolTip property on each control and/or the form  Hover over control to show tool tip  Add HelpProvider control  Set the HelpString on each property and/or the form  Press F1 while the control has focus to show help string

Tab Control  Separate panels to group items  Tab across edge changes panel visibility