Collection in WCF Sevices in VB.NET

Introduction: Collection in WCF. Collections is a way to store any objects in a structured fashion.
 
Collection class has following properties:

• Collections are defined in System.Collections Namespace.
• Most collection classes derive from the interfaces IEnumerable, IList,IDictionary and their generic equivalents.

In this article, I will explain:

• Collection in WCF]
• Concrete collection List<T>
• Interface IEnumerable<T>
• Convert Array at client side to collection.

Step 1: Open visual studio and click on file menu.

• Go to new -> project.
• New project dialog box will appear.
• Select WCF -> WCF Service Application.
• Give the name as you desire.
• Press ok as shown below on figure:

 

• Service1.svc.vb will be open.

Step 2: Go to solution explorer.

• open the Iservice1.vb.
• write a code like:
   

Code:

' Use a data contract as illustrated in the sample below to add composite types to service operations.
<DataContract()> _
Public Class Employee
 
    Public Property Name() As String
        Get
            Return m_Name
        End Get
        Set(value As String)
            m_Name = Value
        End Set
    End Property
    Private m_Name As String
 
    Public Property Empid() As String
        Get
            Return m_Empid
        End Get
        Set(value As String)
            m_Empid = Value
        End Set
    End Property
    Private m_Empid As String
 

End Class

Step 3: Now, open the Service1.svc.vb.

• write the code like:

Code:
' NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.


    public class Service1 : IService1
    {
        List<Employee> lstEmployee = new List<Employee>();
        public List<Employee> GetEmployees(string filter)
        {
            List<Employee> lstEmployee = null;
            using (SqlConnection conn = new SqlConnection("server=.;database="vinit";uid="sa",pwd="wintellect"));
 
 
        }
        public void Add(Employee e)
        {
            lstEmployee.Add(e);
        }

    }

Step 4: Start Debugging by pressing F5.

• A dialog box will appear i.e 'WCF Test Client'.

• Copy the highlighted address as shown below in figure:

 

Step 5: Open the visual studio and go to the file menu.

• Select new -> project.

• Select any type of application. Suppose we add 'Windows Form Application'.

Step 6: Go to Solution Explorer.

• Right click on 'References' and select 'Add Service Reference...'

• 'Add Service Reference' dialog box will appear.

• Paste the address which is copied in step 4.

• Press OK button.

Step 7: Write the code on 'Program.vb' as:

Code:

     Private Shared Sub Main(args As String())
        Dim obj As New ServiceReference1.Service1Client()
              obj.Add(New ServiceReference1.Employee() With { _
                     Key .Name = "vinit", _
                     Key .Empid = "1" _
              })
        Dim lstEmployee As ServiceReference1.Employee() = obj.GetEmployees()
        Console.Read()

    End Sub