в 16:40, 26 мая 2010

2010-05-26T16:40:06Z

Admin: 1 версия

2010-05-26T12:45:32Z

1 версия

Новая страница

==Build an element with a query==

<source lang="vbnet">
Imports System.Collections.Generic
Class Car
Public PetName As String
Public ID As Integer
End Class
Module Program
Sub Main()
Dim data As New List(Of Car)
data.Add(New Car With {.PetName = "A", .ID = 10})
data.Add(New Car With {.PetName = "Pat", .ID = 11})
data.Add(New Car With {.PetName = "Danny", .ID = 12})
data.Add(New Car With {.PetName = "B", .ID = 13})
Dim vehicles As XElement = _
<Inventory>
<%= From c In data _
Select <Car ID=<%= c.ID %>>
<PetName><%= c.PetName %></PetName>
</Car> %>
</Inventory>
Console.WriteLine(vehicles)
End Sub

End Module

</source>

==Build a query to join the two XML trees on the employee"s Id.==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim titles As XElement = XElement.Load("Titles.xml")
Dim query = From emp In employees.<Employee> _
Group Join title In titles.<Title> _
On emp.@id Equals title.@empId _
Into TitleList = Group _
Select EmployeeName = emp.<Name>.Value, _
TitleList
For Each emp In query
Console.WriteLine(emp.EmployeeName)
For Each title In emp.TitleList
Console.WriteLine("{0} - {1}", title.<Name>.Value, title.<Status>.Value)
Next
Next
End Sub
End Class

</source>

==Creating new Xml element in the query==

<source lang="vbnet">
Imports System
Imports System.Reflection
Imports System.Xml
Module Module1
Sub Main()
Dim xml As XElement = XElement.Load("People.xml")
Dim query = From p In xml.Descendants("person"), s In xml.Descendants("id") _
Where p.Element("id").Value = s.Attribute("id").Value _
Select New With {.FirstName = p.Element("firstname").Value, _
.LastName = p.Element("lastname").Value, _
.Amount = s.Attribute("salar").Value}
For Each record In query
Console.WriteLine("Person: {0} {1}, Salary {2}", record.FirstName, _
record.LastName, _
record.Amount)
Next

End Sub
End Module

</source>

==Display the employee names and their hourly rate==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim beforeQuery = From ele In employees.<Employee> Select Name = ele.<Name>.Value, Wage = CDbl(ele.<HourlyRate>.Value)
For Each ele In beforeQuery
Console.WriteLine("{0} gets paid ${1} an hour.", ele.Name, ele.Wage.ToString())
Next
End Sub
End Class

</source>

==Display the employee names and their new hourly rate.==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim afterQuery = From ele In employees.<Employee> Select Name = ele.<Name>.Value, Wage = CDbl(ele.<HourlyRate>.Value)

For Each ele In afterQuery
Console.WriteLine("{0} gets paid ${1} an hour.", ele.Name, ele.Wage.ToString("##.##"))
Next
End Sub
End Class

</source>

==Execute the query and loop through the results, displaying the Information to the screen.==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Imports System.Xml.XPath
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("EmployeesAndTasks.xml")
Dim linqQuery = From task In employees.<Employee>...<Task> _
Select EmployeeName = task.Parent.Parent.<Name>.Value, _
TaskName = task.<Name>.Value, _
task.<Description>.Value _
Order By EmployeeName
For Each task In linqQuery
Console.WriteLine("{0,-15} - {1} ({2})", task.EmployeeName, task.TaskName, task.Description)
Next
End Sub
End Class

</source>

==Loop through all of the Employee elements and remove the HireDate element.==

<source lang="vbnet">

Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
employees.<Employee>.ElementAt(3).Remove()
For Each ele In employees.<Employee>.ToList
ele.SetElementValue("HireDate", Nothing)
Next
Console.WriteLine(employees.ToString)
End Sub
End Class

</source>

==Loop through all the Employee nodes and insert the new "TerminationDate" node and the "Status" attribute==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim newEmployee = <Employee id=<%= 1 %>>
<Name>First</Name>
<Title>Coder</Title>
<HireDate>07/15/2006</HireDate>
<HourlyRate>9.95</HourlyRate>
</Employee>
employees.Add(newEmployee)
For Each ele In employees.<Employee>
ele.Add(<TerminationDate></TerminationDate>)
ele.Add(New XAttribute("Status", ""))
Next
Console.WriteLine(employees.ToString())
End Sub
End Class

</source>

==Loop through all the HourlyRate elements, setting them to the new payrate, which is the old rate * 5%.==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim beforeQuery = From ele In employees.<Employee> Select Name = ele.<Name>.Value, Wage = CDbl(ele.<HourlyRate>.Value)

Dim currentPayRate As Double = 0
For Each ele In employees.<Employee>.<HourlyRate>
currentPayRate = (ele.Value) + ((ele.Value) * 0.05)
ele.SetValue(currentPayRate)
Next
End Sub
End Class

</source>

==Loop through a node in Xml document==

<source lang="vbnet">
Module Program
Sub Main()
Dim doc As XElement = XElement.Load("Inventory.xml")
Dim petNames = From pn In doc...<PetName> Select pn.Value
For Each name In petNames
Console.WriteLine("Name: {0}", name)
Next
End Sub
End Module

</source>

==Query for all of the employees that make (HourlyRate) more than $100 an hour==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim query = From ele In employees.<Employee> _
Where CDbl(ele.<HourlyRate>.Value) >= 100 _
Select ele.@id, ele.<Name>.Value, Pay = CDbl(ele.<HourlyRate>.Value) _
Order By Name
For Each emp In query
Console.WriteLine("[{0,-2}] {1,-25} ${2,-6}", emp.id, emp.Name, emp.Pay.ToString("##.00"))
Next
End Sub
End Class

</source>

==Query the XML Tree and get the Name and Hourly Rate elements.==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("Employees.xml")
Dim afterQuery = From ele In employees.<Employee> Select Name = ele.<Name>.Value, Wage = CDbl(ele.<HourlyRate>.Value)
End Sub
End Class

</source>

==Query Xml document by Node value==

<source lang="vbnet">

Module Program
Sub Main()
Dim doc As XElement = XElement.Load("Inventory.xml")
Dim fords = From c In doc...<Make> Where c.Value = "Ford" Select c
For Each f In fords
Console.WriteLine("Make: {0}", f)
Next
End Sub
End Module

</source>

==Use LINQ to get the tasks for each employee and order them by the employee"s name.==

<source lang="vbnet">
Imports System
Imports System.Xml.Linq
Imports System.Xml.XPath
Public Class MainClass
Public Shared Sub Main()
Dim employees As XElement = XElement.Load("EmployeesAndTasks.xml")
Dim linqQuery = From task In employees.<Employee>...<Task> _
Select EmployeeName = task.Parent.Parent.<Name>.Value, _
TaskName = task.<Name>.Value, _
task.<Description>.Value _
Order By EmployeeName
End Sub
End Class

</source>

==Using For Each to loop through the result of Xml query==

<source lang="vbnet">
Imports System
Imports System.Reflection
Imports System.Xml
Module Module1
Sub Main()
Dim xml As XElement = XElement.Load("People.xml")
Dim query = From s In xml.Elements("salary").Elements("id") _
Where s.Attribute("year").Value = 2004 _
Select s
For Each record In query
Console.WriteLine("Amount: {0}", record.Attribute("salaryyear"))
Next

End Sub
End Module

</source>

← Предыдущая	Версия 16:40, 26 мая 2010
(нет различий)

VB.Net/XML LINQ/Query - История изменений

в 16:40, 26 мая 2010

Admin: 1 версия