Friday, January 30, 2015

Learning WCF



I was used to create web service but then I was once working on a migration application project where I was supposed to convert all web services to WCF services. I was new to it. I still am. But will little hands on experience. Let me share how I learned creating and consuming WCF services
Ok before that. my manager asked me a simple questions . “Supreet, what do you know about message binding, contracts, and endpoints? without which you cannot proceed with it.
I said “I don’t know technical definitions. What I know is you should know:
Where the service located is
How can we communicate or consume the service,
And what the parameters the service seeks are.”
Now that suffices completely. You can now map it with technical jargons.

I thought of simple webpage with functionality of doing mathematical calculation to learn WCF
I created new Projects from Visual studio 2013 of type WCF be application
 

Now I created a class (svc file )which was supposed to be an interface and define the methods to be implemented later . called IMathService.svc
[ServiceContract]
    public interface IMathService
    {
        [OperationContract]
        Int32 Sum(Int32 a, Int32 b);

        [OperationContract]
        Int32 difference(Int32 a, Int32 b);

        [OperationContract]
        Int32 Product(Int32 a, Int32 b);

       
    }
}

Now I declared a class which can actually implement the interface class for maths operation


public class MathService : IMathService
    {
      public  Int32 Sum(Int32 a, Int32 b)
    {
        return a+b;
    }

     
      public  Int32 difference(Int32 a, Int32 b)
{
        return a-b;
}

     
       public Int32 Product(Int32 a, Int32 b)
{
    return a * b;
}
    }
}

Now my service is ready to use.
Let see how we can consume this service. To do that, I created a Simple User Interface which holds UI controls to do maths calculation and display result.
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      num1  <asp:TextBox ID="txt1Num1" runat="server"></asp:TextBox>
       
      num2  <asp:TextBox ID="txtNum2" runat="server"></asp:TextBox>

        <asp:DropDownList ID="DropDownList1" runat="server">
            <asp:ListItem>Add</asp:ListItem>
            <asp:ListItem>sub</asp:ListItem>
            <asp:ListItem>product</asp:ListItem>
        </asp:DropDownList>
     result   <asp:TextBox ID="txtResult" runat="server"></asp:TextBox>
        <asp:Button ID="btnDisplay" runat="server" Text="Display" OnClick="btnDisplay_Click" />
    </div>
       
    </form>
</body>
</html>
Now the most important thing is to add the web reference to consume it
Now on the button click event I implemented the corresponding functionality
using MathApp.ServiceReference1;

namespace MathApp
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        MathServiceClient client = new MathServiceClient();
        protected void Page_Load(object sender, EventArgs e)
        {
    

        }

        protected void btnDisplay_Click(object sender, EventArgs e)
        {
            if(DropDownList1.SelectedItem.Text=="Add")
            {
                var res = client.Sum(Int32.Parse(txt1Num1.Text), Int32.Parse(txtNum2.Text));
                txtResult.Text=res.ToString();
            }
            else if (DropDownList1.SelectedItem.Text == "sub")
            {
                var res = client.difference(Int32.Parse(txt1Num1.Text), Int32.Parse(txtNum2.Text));
                txtResult.Text = res.ToString();
            }
           else
            {
                var res = client.Product(Int32.Parse(txt1Num1.Text), Int32.Parse(txtNum2.Text));
                txtResult.Text = res.ToString();
            }
        }
    }
}
That’s it. You are now ready to test the WCF service. Run the solution
So that’s how I tried to make it very simple to learn how to Create WCF services.
By the way the technically endpoint, binding and contract details are available in the web.config as below
   <endpoint address="http://localhost:18647/MathService.svc" binding="basicHttpBinding"
        bindingConfiguration="BasicHttpBinding_IMathService" contract="ServiceReference1.IMathService"
        name="BasicHttpBinding_IMathService" />
Will post more on advanced way of creating WCF service

 

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