Database operations using Silverlight 2.0 WCF and LINQ to SQL - Developing a WCF Service to interact with LINQ to SQL for all CRUD operations

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Let us start with a new solution:

• Create a new Visual Studio 2008 solution.

• Add a new WCF Service project named “DemoEmpService.”

• Modify all “Service1” to “EmpService” everywhere in the project (steps are shown in my previous articles).

• Add a “LINQ to SQL Classes” item to the project (“DemoEmp.dbml”)

• Using “Server Explorer,” drag and drop “Emp” and “Dept” tables as shown in the following image.

• Modify “IEmpService.vb” as shown below:

<ServiceContract()> _

Public Interface IEmpService

<OperationContract()> _

Function GetEmployee(ByVal empno As Integer) As Emp

<OperationContract()> _

Function GetEmployeeList() As List(Of Emp)

<OperationContract()> _

Sub Add(ByVal objEmp As Emp)

<OperationContract()> _

Sub Update(ByVal objEmp As Emp)

<OperationContract()> _

Sub Delete(ByVal empno As Integer)

End Interface

• Implement the same in “EmpService” (service) class as follows:

Imports System.Data.Linq

Public Class EmpService

Implements IEmpService

Public Sub New()

End Sub

Public Function GetEmployeeList() As System.Collections.Generic.List(Of Emp) Implements IEmpService.GetEmployeeList

Using ctxt As New DemoEmpDataContext

ctxt.ObjectTrackingEnabled = False

Return ctxt.Emps.ToList

End Using

End Function

Public Sub Add(ByVal objEmp As Emp) Implements IEmpService.Add

Using ctxt As New DemoEmpDataContext

'adding a new row

ctxt.GetTable(Of Emp).InsertOnSubmit(objEmp)

'saving rows added

ctxt.SubmitChanges()

End Using

End Sub

Public Sub Delete(ByVal empno As Integer) Implements IEmpService.Delete

Using ctxt As New DemoEmpDataContext

Dim objEmpOld As Emp = ctxt.GetTable(Of Emp).SingleOrDefault(Function(p) p.Empno = empno)

If objEmpOld IsNot Nothing Then

'delete row

ctxt.GetTable(Of Emp).DeleteOnSubmit(objEmpOld)

'save changes

ctxt.SubmitChanges()

End If

End Using

End Sub

Public Function GetEmployee(ByVal empno As Integer) As Emp Implements IEmpService.GetEmployee

Dim objEmp As Emp = Nothing

Using ctxt As New DemoEmpDataContext

'retrieve emp row

objEmp = ctxt.GetTable(Of Emp).SingleOrDefault(Function(p) p.Empno = empno)

End Using

Return objEmp

End Function

Public Sub Update(ByVal objEmp As Emp) Implements IEmpService.Update

Using ctxt As New DemoEmpDataContext

Dim objEmpOld As Emp = ctxt.GetTable(Of Emp).SingleOrDefault(Function(p) p.Empno = objEmp.Empno)

If objEmpOld IsNot Nothing Then

'modify row

objEmpOld.Ename = objEmp.Ename

objEmpOld.Sal = objEmp.Sal

objEmpOld.Deptno = objEmp.Deptno

'save changes

ctxt.SubmitChanges()

End If

End Using

End Sub

End Class

Next: Developing a Silverlight 2.0 page to demonstrate CRUD functionality >>
 

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Comments On: Database operations using Silverlight 2.0 WCF and LINQ to SQL

· Hai,This is my next in series focusing on development using Silverlight 2.0, WCF...    · Excellent Article. But is it the best solution or there are any other solutions as...   >>> Post your comment now!