c# - 从 UWP 中的数据库检索数据

Question

我正在尝试从 Azure 上的 SQLDatabase 检索数据列表，并将其绑定(bind)到 Windows 10 通用应用程序中的 ListView 上。我所做的是创建一个用于检索数据的 WCF 服务，然后在 azure 上发布，之后在我的应用程序上调用此服务。

我当前的代码有错误。 这是我的 IService1.cs 代码

namespace WcfService2
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
    [ServiceContract]
    public interface IService1
    {
        // TODO: Add your service operations here
        [OperationContract]
        List<NYPUnlocking> NYP_GetLockerStatus();
    }


    // Use a data contract as illustrated in the sample below to add composite types to service operations.
    [DataContract]
    public class NYPUnlocking
    {
        [DataMember]
        public int lockerID { get; set; }
        [DataMember]
        public string lockStatus { get; set; }
    }

}

Service1.svc.cs:

namespace WcfService2
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.
    // NOTE: In order to launch WCF Test Client for testing this service, please select Service1.svc or Service1.svc.cs at the Solution Explorer and start debugging.
    public class Service1 : IService1
    {
       public List<NYPUnlocking> NYP_GetLockerStatus()
        {
            SqlConnection conn = new SqlConnection("Copy ADO.net connection string");
            string sqlStr = "SELECT * FROM dbo.lockerStatus";
            SqlCommand cmd = new SqlCommand(sqlStr, conn);
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            List<NYPUnlocking> ret = new List<NYPUnlocking>();
            while (dr.Read())
            {
                NYPUnlocking unlock = new NYPUnlocking()
                {
                    lockerID = Int32.Parse(dr["lockerID"].ToString()),
                    lockStatus = dr["lockStatus"].ToString()
                };

                ret.Add(unlock);
            }
            conn.Close();

            return ret;
        }
    }
}

然后，我将其发布到 Azure 上，并在我的 UWP 应用程序上添加对 Azure 网站的服务引用。以下代码是我的XAML和cs代码。

我在 x:DataType="data:NYPUnlocking"处遇到错误，错误提示“ namespace “using:NYPUnlock.ServiceReference1”中不存在名称“NYPUnlocking”。

<Page.Resources>
    <DataTemplate x:DataType="data:NYPUnlocking" x:Key="UserTemplate">
        <StackPanel Orientation="Horizontal" Padding="0,0,0,0">
            <TextBlock FontSize="12" Text="{x:Bind lockerID}" HorizontalAlignment="Left" Width="200" />
            <TextBlock FontSize="12" Text="{x:Bind lockStatus}" HorizontalAlignment="Right" Width="200" />
        </StackPanel>
    </DataTemplate>
</Page.Resources>

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" Width="354">
        <ListView x:Name="lvLocker" ItemTemplate="{StaticResource UserTemplate}"/>
        <TextBox x:Name="tbError" TextWrapping="Wrap" Text="Error"/>
    </StackPanel>
</Grid>

我的cs文件在await task1处出现错误，提示“无法将类型'System.Collections.ObjectModel.ObservableCollection'隐式转换为'NYPUnlock.ServiceReference1.NYPUnlocking[]'

namespace NYPUnlock
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
            getStatus();
        }
        public async void getStatus()
        {
            try
            {
                ServiceReference1.Service1Client client = new ServiceReference1.Service1Client(ServiceReference1.Service1Client.EndpointConfiguration.BasicHttpBinding_IService1);
                var task1 = client.NYP_GetLockerStatusAsync();
                ServiceReference1.NYPUnlocking[] returnResult = await task1;
                lvLocker.ItemsSource = returnResult;
            }
            catch(Exception ex)
            {
                tbError.Text = ex.Message;
            }
        }
    }
}

我认为我做的一切都是正确的，是什么导致了这个问题？非常感谢任何帮助，谢谢!

Answer 1

尝试一下:

• 将名为“whatevername”的引用添加到 XAML 文件中的命名空间 WcfService2，并在 x:DataType="data:NYPUnlocking" 中使用此前缀而不是“data:”

• 将 returnResult 的声明替换为 var 类型，而不是 ServiceReference1.NYPUnlocking[]类型