IService1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace WCF_DataLayer
{
    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
         List GetWCFdata();
        [OperationContract]
        void SubmitData(WCF_Data myData);
        [OperationContract]
        List GetDataFromServer();
        [OperationContract]
        void SetWCFdata(WCF_Data myData);
    }
    
    [DataContract]
    public class WCF_Data
    {
        [DataMember]
        public string uname
        {
            get;
            set;
        }
        [DataMember]
        public string address
        {
            get;
            set;
        }
        [DataMember]
        public int phone
        {
            get;
            set;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace WCF_DataLayer
{
    public class Service1 : IService1
    {
        List DataToSave = new List();

        public List GetWCFdata()
        {
            List myData = new List();
            SqlConnection conn = null;
            SqlCommand cmd = null;
            SqlDataReader sdr = null;
            try
            {
                conn = new SqlConnection(@"server=zayyaroo\shop1;database=test;
uid=sa;pwd=123;");
                conn.Open();
                cmd = new SqlCommand("SELECT * FROM WCF_data", conn);
                sdr = cmd.ExecuteReader();
                while (sdr.Read())
                {
                    WCF_Data data = new WCF_Data();
                    data.uname = sdr["uname"].ToString();
                    data.address = sdr["address"].ToString();
                    data.phone = int.Parse(sdr["phone"].ToString());
                    myData.Add(data);
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (sdr != null)
                    sdr.Dispose();
                if (conn != null)
                    conn.Dispose();
                if (cmd != null)
                    cmd.Dispose();
            }
            return myData;
            conn.Close();
        }
        public void SubmitData(WCF_Data myData)
        {
            DataToSave.Add(myData);
        }
        public List GetDataFromServer()
        {
            return DataToSave;
        }
        public void SetWCFdata(WCF_Data myData)
        {
            SqlConnection connection = new SqlConnection(@"server=zayyaroo\shop1;
database=test;uid=sa;pwd=123;");         
            connection.Close();
            connection.Open();
            SqlTransaction tran = connection.BeginTransaction();
            SqlCommand command = new SqlCommand("INSERT INTO [WCF_data](uname,address,phone)"
                + "VALUES(@uname,@addr,@phone)", connection, tran);
            try
            {
                command.Parameters.Add("@uname", SqlDbType.NVarChar, 50).Value = myData.uname.ToString();
                command.Parameters.Add("@addr", SqlDbType.NVarChar, 50).Value = myData.address.ToString();
                command.Parameters.Add("@phone", SqlDbType.Int).Value = int.Parse(myData.phone.ToString());
                command.ExecuteNonQuery();
                tran.Commit();
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                connection.Close();
            }           
        }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WinForm
{
    public partial class Form1 : Form
    {
        ServiceReference1.Service1Client svcClient = null;
        ServiceReference1.WCF_Data oneData = new
WinForm.ServiceReference1.WCF_Data();    
       
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            svcClient = new ServiceReference1.Service1Client();
            svcClient.Open();  
        }
        private void btnAdd_Click(object sender, EventArgs e)
        {           
            oneData.uname = tbUname.Text;
            oneData.address = tbAddr.Text;
            oneData.phone = int.Parse(tbPhone.Text);
            svcClient.SubmitData(oneData);
            svcClient.SetWCFdata(oneData);
        }
        private void btnSend_Click(object sender, EventArgs e)
        {
            dataGridView1.DataSource = svcClient.GetDataFromServer();
            dataGridView2.DataSource = svcClient.GetWCFdata();            
        }
        private void Form_closing(object sender, FormClosingEventArgs e)
        {
            svcClient.Close();
            svcClient = null;
        }
    }
}