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Connexion 14.5+ includes a framework to communicate directly with your server-side device from the associated device user-interface. This is often useful in if you need to query for server-side state, perform a database lookup or connection availability, or run a specific method on the server.
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public interface IDiagnostics
{
stringTask<string> GetDiagnosticsGetDiagnosticsAsync();
} |
Next, implement the interface in your device:
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using System;
using System.Threading;
using Connexion.Core;
using System.Threading.Tasks;
namespace ProxySample1
{
[DevicePlugin("ProxySample1", "Example of device proxying", DeviceDefinitionFlags.None, typeof(object), typeof(object), typeof(ProxySample1Factory))]
public class ProxySample1 : BaseDevice<ProxySample1Configuration>, IDiagnostics
{
public override void Start()
{
}
public override void Stop()
{
}
public override async Task ProcessMessageAsync(IMessageContext context, CancellationToken token)
{
}
public stringasync Task<string> GetDiagnosticsGetDiagnosticsAsync()
{
return Task.FromResult(Environment.MachineName);
}
}
} |
Now, create a proxy variable in your viewmodel. Note that if you are calling a proxy method in your viewmodel constructor, we recommend you perform this proxy calls on a different thread so that you do not block the UI thread.
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using Connexion.Core;
using System.Threading.Tasks;
using System.Windows.Input;
namespace ProxySample1
{
public class ProxySample1UIViewModel : ViewModelBase
{
private ProxySample1Configuration m_Config;
private IDeviceUIParams m_DeviceUIParams;
private IDiagnostics m_Proxy;
public ProxySample1UIViewModel(ProxySample1Configuration config, IDeviceUIParams deviceUIParams)
{
m_Config = config;
m_DeviceUIParams = deviceUIParams;
m_Proxy = deviceUIParams.GetServerDeviceProxy<IDiagnostics>(); // <-- creation of the proxy
}
public ProxySample1Configuration Configuration
{
get { return m_Config; }
}
private RelayCommand m_GetDiagnosticsCommand;
public ICommand GetDiagnosticsCommand
{
get { return m_GetDiagnosticsCommand ?? (m_GetDiagnosticsCommand = new RelayCommand(async p => await GetDiagnostics())); }
}
private async Task GetDiagnostics()
{
await Task.Run(() =>
{
try
{
DiagnosticResult = await m_Proxy.GetDiagnosticsGetDiagnosticsAsync(); // <-- Calling the server
}
catch(exception ex)
{
DiagnosticResult = ex.Message;
});
}
private string m_DiagnosticResult = "Click to run the diagnostics";
public string DiagnosticResult
{
get { return m_DiagnosticResult; }
set
{
if(m_DiagnosticResult != value)
{
m_DiagnosticResult = value;
RaisePropertyChanged();
}
}
}
}
}
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