Page.xaml

<UserControl x:Class="SilverlightApplication15.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"
    >
    <Grid x:Name="LayoutRoot" Background="White" Loaded="LayoutRoot_Loaded">
        <data:DataGrid x:Name="dgrd_DataGrid" Margin="5" AutoGenerateColumns="False" >
            <data:DataGrid.Columns>
                <data:DataGridTextColumn Header="姓名" Width="150" 
                                         Binding="{Binding UserName}">
                </data:DataGridTextColumn>
                <data:DataGridTextColumn Header="年龄" Width="150" 
                                         Binding="{Binding UserAge}">
                </data:DataGridTextColumn> "
            </data:DataGrid.Columns>
        </data:DataGrid>
    </Grid>
</UserControl>

Page.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Collections.ObjectModel;namespace SilverlightApplication15
{
    public partial class Page : UserControl
    {
        public Page()
        {
            InitializeComponent();
            
        }
        void GetUser()
        {
            UserService.Service1SoapClient userService = new SilverlightApplication15.UserService.Service1SoapClient();
            userService.GetUserCompleted += new EventHandler<SilverlightApplication15.UserService.GetUserCompletedEventArgs>(userService_GetUserCompleted);
            userService.GetUserAsync();

        }

WebService中仅包含一个返回List<User>的GetUser();

PS：在Silverlight中并不包含DataGrid，如需使用，请引用System.Windows.Controls.Data

并且在Page.xaml中声明

xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"