使用wcf在silverlight中绑定组合框有问题

Question

i am trying to bind combobox in silverlight using WCF. i have tried below code but comobobox doesn't display any values??.. code as follows..

 public class Appsrvvice : IAppsrvvice
 {

    public void DoWork()
    {
     }

    public List<fillupcombox> fillup()
    {
        List<string> x=new List<string>();
        List<string> y=new List<string>();

        string connectionstring = "server=localhost;User Id=root;password=root;Persist Security Info=True;database=mv_store";
        string msg;

         msg = "";
        MySqlConnection con = new MySqlConnection(connectionstring);
        MySqlDataAdapter ad = new MySqlDataAdapter("select Product_Name,Product_Id from product_detail Order by Product_Name", con);

        DataTable dt = new DataTable();

        try
        {
            ad.Fill(dt);
          //  return dt;

            for(int i=0;i<dt.Rows.Count;i++)
            {
                x.Add(dt.Rows[i]["Product_Name"].ToString());
                y.Add(dt.Rows[i]["Product_Id"].ToString());
            }

        }

        catch (Exception e)
        {

            msg = e.Message;
            return null;

        }
        finally
        {
            ad.Dispose();
        }


        return new List<fillupcombox>()
        {
            new fillupcombox()
            {
                Texts=x,
                Valuess=y
            }
        };
    }
}



[ServiceContract]
public interface IAppsrvvice
{

    [OperationContract]
    void DoWork();

    [OperationContract]
    List<fillupcombox> fillup();

}

[DataContract]
public class fillupcombox
{

    [DataMember]
    public List<string> Texts
    {
        get;
        set;
    }

    [DataMember]
    public List<string> Valuess
    {
        get;
        set;

    }

}

Heres My main page code

 public MainPage()

 {
        InitializeComponent();

        ServiceReference1.AppsrvviceClient obj = new ServiceReference1.AppsrvviceClient();
        obj.fillupCompleted += new EventHandler<ServiceReference1.fillupCompletedEventArgs>(fillupCompletedp);
        obj.fillupAsync();



    }


    public void fillupCompletedp(object sender, ServiceReference1.fillupCompletedEventArgs e)
    {


         comboBox1.ItemsSource =e.Result;


    }


<UserControl x:Class="SilverlightApplication1comobobox.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:DesignHeight="300" d:DesignWidth="400">

<Grid x:Name="LayoutRoot" Background="White">
    <ComboBox Height="23"  HorizontalAlignment="Left" Margin="70,67,0,0" Name="comboBox1" VerticalAlignment="Top" Width="120" />
</Grid>

No Values is populated in the combobox. Any idea where i am wrong?

Answer 1

I had the same problem, So I decided to make it as basic as posible.

public List<string> GetTypes()
    {
        NissanDBEntities niss = new NissanDBEntities();
        return niss.cars.Select(m => m.type).Distinct().ToList();
    }


public Clients()
    {
        InitializeComponent();
        NissanSvc.NissanServiceClient proxy = new Nissan.NissanSvc.NissanServiceClient();
        proxy.GetTypesCompleted += new EventHandler<NissanSvc.GetTypesCompletedEventArgs (proxy_GetTypesCompleted);
        proxy.GetTypesAsync();
    }

    void proxy_GetTypesCompleted(object sender, NissanSvc.GetTypesCompletedEventArgs e)
    {
        this.cmbType.ItemsSource = e.Result;
    }

Hope it helps.

Answer 2

comboBox1.ItemsSource = e.Result;

Answer 3

You are returning an object with 2 Lists. the client is not able to determine how to display them. I suggest you change the structure into a List/Array of items, say:

class Pair
{
    public string Key;
    public string Value;
}

And return an array of Pairs from the service.

Then add a DataTemplate to the ComboBox so it knows how to display a Pair:

<ComboBox ...>
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                 <TextBlock Text="{Binding Key}"/>
                 <TextBlock Text="{Binding Value}"/>
            </StackPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>