Contains the OPC UA service result of the failed conversion.
Syntax
[JetBrains.Annotations.NotNull()]
public UAServiceResult ServiceResult {get; set;}
Property Value
The value of this property cannot be null
(Nothing
in Visual Basic).
Because there is an implicit conversion to OpcLabs.EasyOpc.UA.UACodeBits from OpcLabs.EasyOpc.UA.UAServiceResult, you can simply use the return value in place of a OpcLabs.EasyOpc.UA.UACodeBits (representing the code bits of the status code). When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.UA.UAServiceResult.ToUACodeBits method instead.
Exceptions
Exception | Description |
System.ArgumentNullException |
A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.
This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception. |
Example
// This example shows how to handle conversion errors on the server level.
// You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client, server and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-OPCStudio-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.
using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.NodeSpace;
using OpcLabs.EasyOpc.UA.OperationModel;
namespace UAServerDocExamples._EasyUAServer
{
class ConversionError
{
public static void Main1()
{
// Instantiate the server object.
// By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
var server = new EasyUAServer();
// Define a data variable of type Byte.
UADataVariable dataVariable = UADataVariable.CreateIn(server.Objects, "MyDataVariable").ValueType<byte>();
// Add a Read handler that returns random values between 0 and 511. Those greater than 255 will cause conversion
// errors.
var random = new Random();
dataVariable.Read += (sender, args) => args.HandleAndReturn(random.Next(0, 512));
// Hook events to the server.
// Note that the conversion error event can also be handled on the data variable or folder level, if that's what
// you requirements call for.
server.ConversionError += ServerOnConversionError;
// Start the server.
Console.WriteLine("The server is starting...");
server.Start();
Console.WriteLine("The server is started.");
Console.WriteLine();
// Let the user decide when to stop.
Console.WriteLine("Press Enter to stop the server...");
Console.ReadLine();
// Stop the server.
Console.WriteLine("The server is stopping...");
server.Stop();
Console.WriteLine("The server is stopped.");
}
// Event handler for the ConversionError event. It simply prints out the event.
static private void ServerOnConversionError(object sender, UADataVariableConversionErrorEventArgs e)
{
Console.WriteLine();
Console.WriteLine($"*** {e}");
// Following are some useful properties in the event notification:
// e.DataVariable
// e.Action
// e.ServiceResult
switch (e.Action)
{
case UADataVariableConversionAction.Read:
Console.WriteLine("The conversion error occurred during a Read operation.");
break;
case UADataVariableConversionAction.Write:
Console.WriteLine("The conversion error occurred during a Write operation.");
break;
case UADataVariableConversionAction.Update:
Console.WriteLine("The conversion error occurred during an Update operation.");
break;
}
Console.WriteLine($"It occured on the data variable: {e.DataVariable}.");
Console.WriteLine($"The service result was: {e.ServiceResult.Message}");
}
}
}
' This example shows how to handle conversion errors on the server level.
' You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.
Imports System
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.NodeSpace
Imports OpcLabs.EasyOpc.UA.OperationModel
Namespace _EasyUAServer
Partial Friend Class ConversionError
Shared Sub Main1()
' Instantiate the server object.
' By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
Dim server = New EasyUAServer()
' Define a data variable of type Byte.
Dim dataVariable As UADataVariable = UADataVariable.CreateIn(server.Objects, "MyDataVariable").ValueType(Of Byte)()
' Add a Read handler that returns random values between 0 and 511. Those greater than 255 will cause conversion
' errors.
Dim random = New Random()
AddHandler dataVariable.Read, Sub(sender, args) args.HandleAndReturn(random.Next(0, 512))
' Hook events to the server.
' Note that the conversion error event can also be handled on the data variable or folder level, if that's what
' you requirements call for.
AddHandler server.ConversionError, AddressOf ServerOnConversionError
' Start the server.
Console.WriteLine("The server is starting...")
server.Start()
Console.WriteLine("The server is started.")
Console.WriteLine()
' Let the user decide when to stop.
Console.WriteLine("Press Enter to stop the server...")
Console.ReadLine()
' Stop the server.
Console.WriteLine("The server is stopping...")
server.Stop()
Console.WriteLine("The server is stopped.")
End Sub
' Event handler for the ConversionError event. It simply prints out the event.
Private Shared Sub ServerOnConversionError(ByVal sender As Object, ByVal e As UADataVariableConversionErrorEventArgs)
Console.WriteLine()
Console.WriteLine($"*** {e}")
' Following are some useful properties in the event notification:
' e.DataVariable
' e.Action
' e.ServiceResult
Select Case e.Action
Case UADataVariableConversionAction.Read
Console.WriteLine("The conversion error occurred during a Read operation.")
Case UADataVariableConversionAction.Write
Console.WriteLine("The conversion error occurred during a Write operation.")
Case UADataVariableConversionAction.Update
Console.WriteLine("The conversion error occurred during an Update operation.")
End Select
Console.WriteLine($"It occured on the data variable: {e.DataVariable}.")
Console.WriteLine($"The service result was: {e.ServiceResult.Message}")
End Sub
End Class
End Namespace
Requirements
Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows
See Also