Introduction to Binding ComboBox and DataGrid Controls in Silverlight 2.0 - Developing WCF Service to serve Business (Entity) Objects collection using LINQ to SQL

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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.”

• Change “Service1” to “EmpService” throughout 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()> _

Function GetDepartmentList() As List(Of Dept)

<OperationContract()> _

Function GetEmployeeListByDept(ByVal deptno As Integer) As List(Of Emp)

End Interface

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

Imports System.Data.Linq

' NOTE: If you change the class name "Service1" here, you must also update the reference to "Service1" in Web.config and in the associated .svc file.

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 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 Function GetDepartmentList() As System.Collections.Generic.List(Of Dept) Implements IEmpService.GetDepartmentList

Using ctxt As New DemoEmpDataContext

ctxt.ObjectTrackingEnabled = False

Return ctxt.Depts.ToList

End Using

End Function

Public Function GetEmployeeListByDept(ByVal deptno As Integer) As System.Collections.Generic.List(Of Emp) Implements IEmpService.GetEmployeeListByDept

Using ctxt As New DemoEmpDataContext

Dim opt As New DataLoadOptions

opt.LoadWith(Of Dept)(Function(d) d.Emps)

ctxt.LoadOptions = opt

ctxt.ObjectTrackingEnabled = False

 

Dim oDept As Dept = ctxt.Depts.Where(Function(d) d.Deptno = deptno).FirstOrDefault

Return If(oDept Is Nothing, Nothing, oDept.Emps.ToList)

End Using

End Function

End Class

Next: Binding Object Collections Silverlight 2.0 ComboBox control dynamically >>
 

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