silverlight datagrid绑定问题

[yc1023451515]

profiler中执行信息:
SQL:BatchStarting select * from GuestBookContent order by ID asc
SQL:BatchCompleted select * from GuestBookContent order by ID asc
为什么只调用一次查询,会执行两次这个方法(也就是执行了两次查询)?

代码如下:
1.ServicesDB:

 [OperationContract]
    public List<ContentInfo> QueryContent()
    {
        List<ContentInfo> m_ContentInfo = new List<ContentInfo>();
        using (SqlDataReader dr = SqlHelper.ExecuteReader(CommandType.Text, "select  * from GuestBookContent order by ID asc"))
        {
            while (dr.Read())
            {
                ContentInfo model = new ContentInfo();
                model.ID = Convert.ToInt32(dr["ID"]);
                model.Name = dr["Name"].ToString();
                model.Email = dr["Email"].ToString();
                model.Logo = dr["Logo"].ToString();
                model.Content = dr["Content"].ToString();
                model.Addtime = DateTime.Parse(dr["Addtime"].ToString());
                model.Ip = dr["Ip"].ToString();
                m_ContentInfo.Add(model);
            }
        }
        return m_ContentInfo;
    }

2.MainPage.xaml.cs:

namespace DataGridDemo
{
    public partial class MainPage: UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            this.Loaded+=new RoutedEventHandler(MainPage_Loaded);
        }
        protected void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            EndpointAddress address = new EndpointAddress(new Uri(Application.Current.Host.Source, "/DBService.svc"));
            ServiceDB.ServiceDBClient db = new DataGridDemo.ServiceDB.ServiceDBClient();
            db.QueryContentCompleted+=new EventHandler<DataGridDemo.ServiceDB.QueryContentCompletedEventArgs>(db_QueryContentCompleted);
            db.QueryContentAsync();
        }

        protected void db_QueryContentCompleted(object sender, QueryContentCompletedEventArgs e)
        {
            if (null == e.Error)
            {
                this.dgContent.ItemsSource = e.Result;
            }
        }
    }
}

3.MainPage.xaml

<UserControl xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"  x:Class="DataGridDemo.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
  <Grid x:Name="LayoutRoot">
    <data:DataGrid x:Name="dgContent"></data:DataGrid>
  </Grid>
</UserControl>

[helloWorld1209]

调用到QueryContentAsync（）方法的函数只是MainPage_Loaded，你调试过吗？

MainPage_Loaded方法是调用一次还是二次？

或者把
ServiceDB.ServiceDBClient db = new DataGridDemo.ServiceDB.ServiceDBClient();
db.QueryContentCompleted+=new EventHandler<DataGridDemo.ServiceDB.QueryContentCompletedEventArgs>(db_QueryContentCompleted);
db.QueryContentAsync();
直接放到构造函数里试试

[yc1023451515]

[Quote=引用 2 楼 jimmy_xiao0010 的回复:]
调用到QueryContentAsync（）方法的函数只是MainPage_Loaded，你调试过吗？

MainPage_Loaded方法是调用一次还是二次？

或者把
ServiceDB.ServiceDBClient db = new DataGridDemo.ServiceDB.ServiceDBClient();
db.QueryContentCompleted+=n……
[/Quote]
调用到QueryContentAsync（）只有一个地方,就是MainPage_Loaded中
我把代码贴到构造函数里面运行也是一样执行两次

[helloWorld1209]

这么奇怪？ MainPage 初始化了2次？？

这个跟datagrid是没有关系的

[yc1023451515]

[Quote=引用 4 楼 jimmy_xiao0010 的回复:]
这么奇怪？ MainPage 初始化了2次？？

这个跟datagrid是没有关系的
[/Quote]

应该不是程序的问题,在查询分析器里面也是记录两条

谢谢哈