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General

Icon:

The OPC-UA Data Dialog (UADataDialog class) allows the user to interactively select the OPC data node residing in a specific OPC Unified Architecture server. It also has a different mode (controlled by the UserPickEndpoint property) which allows the user to start the node selection by choosing the host and server endpoint first.

Here is an example of OPC-UA Data dialog in action:

In the default mode (when UserPickEndpoint is false), your code should set the EndpointDescriptor property to specify the OPC Unified Architecture server whose nodes are to be browsed. If you want the user to pick the endpoint, set the UserPickEndpoint property to true; in this case, setting the EndpointDescriptor is not needed on input.

After setting the inputs as needed, your code calls the ShowDialog method. If the result is equal to DialogResult.OK, the user has selected the OPC data node, and information about it can be retrieved from the NodeElement (and also NodeDescriptor) property. If UserPickEndpoint is true, the chosen server endpoint can be retrieved from the EndpointDescriptor property.

The user can browse through the UA Objects, and select from Data Variables or Properties.

.NET

// This example shows how to let the user browse for an OPC-UA data node (a Data Variable or a Property). 

using System.Windows.Forms;
using OpcLabs.EasyOpc.UA.Forms.Browsing;

namespace UAFormsDocExamples._UADataDialog
{
    static partial class ShowDialog
    {
        public static void Main1(IWin32Window owner)
        {
            var dataDialog = new UADataDialog
            {
                EndpointDescriptor = {UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" },
                // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
                // or "https://opcua.demo-this.com:51212/UA/SampleServer/"
                UserPickEndpoint = true
            };

            DialogResult dialogResult = dataDialog.ShowDialog(owner);
            if (dialogResult != DialogResult.OK)
                return;

            // Display results
            MessageBox.Show(owner, 
                $"EndpointDescriptor: {dataDialog.EndpointDescriptor}\r\n" +
                $"NodeElement: {dataDialog.NodeElement}");
        }
    }
}

# This example shows how to let the user browse for an OPC-UA data node
# (a Data Variable or a Property).

using namespace OpcLabs.EasyOpc.UA.Forms.Browsing

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcForms.dll"

# Instantiate the dialog object.
$dataDialog = New-Object UADataDialog
$dataDialog.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
$dataDialog.UserPickEndpoint = $true

$dialogResult = $dataDialog.ShowDialog()
if ($dialogResult -ne [System.Windows.Forms.DialogResult]::OK) {
    return
}

# Display results
Write-Host "EndpointDescriptor: $($dataDialog.EndpointDescriptor)"
Write-Host "NodeElement: $($dataDialog.NodeElement)"

# This example shows how to let the user browse for an OPC-UA data node (a Data Variable or a Property).

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System.Windows.Forms import *
from OpcLabs.EasyOpc.UA.Forms.Browsing import *


dataDialog = UADataDialog()
dataDialog.EndpointDescriptor.UrlString = 'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer'
# or 'http://opcua.demo-this.com:51211/UA/SampleServer' (currently not supported)
# or 'https://opcua.demo-this.com:51212/UA/SampleServer/'
dataDialog.UserPickEndpoint = True

dialogResult = dataDialog.ShowDialog()
print(dialogResult)
if dialogResult != DialogResult.OK:
    exit()

# Display results.
print('EndpointDescriptor: ', dataDialog.EndpointDescriptor, sep='')
print('NodeElement: ', dataDialog.NodeElement, sep='')

print('Finished.')

COM

// This example shows how to let the user browse for an OPC-UA data node (a Data Variable or a Property).

#include "stdafx.h"    // Includes "QuickOpc.h", and other commonly used files
#include "ShowDialog.h"

namespace _UADataDialog
{
    void ShowDialog::Main()
    {
        // Initialize the COM library
        CoInitializeEx(NULL, COINIT_MULTITHREADED);
        {
            // 
            _UADataDialogPtr DataDialogPtr(__uuidof(UADataDialog));

            //
            DataDialogPtr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            DataDialogPtr->UserPickEndpoint = true;

            // 
            DialogResult dialogResult = DataDialogPtr->ShowDialog(NULL);
            // Display results

            if (dialogResult == 1/*OK*/)
            {
                _tprintf(_T("%d\n"), dialogResult);
                _tprintf(_T("EndpointDescriptor: %s\n"), (LPCTSTR)CW2CT(DataDialogPtr->EndpointDescriptor->ToString));
                _tprintf(_T("NodeElement: %s\n"), (LPCTSTR)CW2CT(DataDialogPtr->NodeElement->ToString));
            }
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

// This example shows how to let the user browse for an OPC-UA data node
// (a Data Variable or a Property).

class procedure ShowDialog.Main;
var
  DataDialog: UADataDialog;
begin
  // Instantiate the dialog object
  DataDialog := CoUADataDialog.Create;

  DataDialog.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  DataDialog.UserPickEndpoint := True;

  DataDialog.ShowDialog(nil);
  // IMPROVE: check the dialog result

  // Display results
  WriteLn('EndpointDescriptor: ', DataDialog.EndpointDescriptor.ToString);
  WriteLn('NodeElement: ', DataDialog.NodeElement.ToString);
end;

// This example shows how to let the user browse for an OPC-UA data node
// (a Data Variable or a Property).

class procedure ShowDialog.Main;
var
  DataDialog: OpcLabs_EasyOpcForms_TLB._UADataDialog;
  DialogResult: System_Windows_Forms_TLB.DialogResult;
begin
  // Instantiate the dialog object
  DataDialog := CoUADataDialog.Create;

  DataDialog.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  DataDialog.UserPickEndpoint := True;

  DialogResult := DataDialog.ShowDialog(nil);
  WriteLn(DialogResult);

  if DialogResult <> DialogResult_OK then
    Exit;

  // Display results
  WriteLn('EndpointDescriptor: ', DataDialog.EndpointDescriptor.ToString);
  WriteLn('NodeElement: ', DataDialog.NodeElement.ToString);
end;

Rem This example shows how to let the user browse for an OPC-UA data node (a Data Variable or a Property).

Private Sub ShowDialog_Main_Command_Click()
    OutputText = ""

    Dim DataDialog As New UADataDialog
    DataDialog.endpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    DataDialog.UserPickEndpoint = True
    
    Dim DialogResult
    DialogResult = DataDialog.ShowDialog
    
    OutputText = OutputText & DialogResult & vbCrLf
    If DialogResult <> 1 Then   ' OK
        Exit Sub
    End If
    
    ' Display results
    OutputText = OutputText & "EndpointDescriptor: " & DataDialog.endpointDescriptor & vbCrLf
    OutputText = OutputText & "NodeElement: " & DataDialog.NodeElement & vbCrLf
End Sub

Rem This example shows how to let the user browse for an OPC-UA data node (a Data Variable or a Property). 

Option Explicit

Const DialogResult_OK = 1

Dim DataDialog: Set DataDialog = CreateObject("OpcLabs.EasyOpc.UA.Forms.Browsing.UADataDialog")
DataDialog.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
DataDialog.UserPickEndpoint = True

Dim dialogResult: dialogResult = DataDialog.ShowDialog
WScript.Echo dialogResult

If dialogResult <> DialogResult_OK Then
    WScript.Quit
End If

' Display results
WScript.Echo "EndpointDescriptor: " & DataDialog.EndpointDescriptor
WScript.Echo "NodeElement: " & DataDialog.NodeElement

Multi-selection

When you set the MultiSelect property of the UADataDialog to true, the dialog will allow the user to select any number of OPC-UA nodes. The list below the folders and data nodes (labeled “Selected nodes”) contains the set of nodes that the user has selected in the dialog. The user can freely add nodes to this list, or remove them. The selected set is carried over to next invocation of the dialog, unless you change it from the code.

In the multi-selection mode, the set of nodes selected on input (if any) is in the NodeDescriptors property. On the output, the dialog fills the information about selected nodes into the NodeElements property (and updated the NodeDescriptors property as well).

If UserPickEndpoint is true, each node may come from a different server. In this case, the EndpointDescriptors array contains the server endpoints for each node in NodeDescriptors, with corresponding indices in both arrays. The arrays must have the same length.

C#
Python (.NET)

// This example shows how to let the user browse for multiple OPC-UA data nodes (data variables or properties). 

using System;
using System.Linq;
using System.Windows.Forms;
using OpcLabs.EasyOpc.UA.Forms.Browsing;

namespace UAFormsDocExamples._UADataDialog
{
    static partial class ShowDialog
    {
        public static void MultiSelect(IWin32Window owner)
        {
            var dataDialog = new UADataDialog
            {
                EndpointDescriptor = { UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" },
                // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
                // or "https://opcua.demo-this.com:51212/UA/SampleServer/"
                MultiSelect = true,
                UserPickEndpoint = true
            };

            DialogResult dialogResult = dataDialog.ShowDialog(owner);
            if (dialogResult != DialogResult.OK)
                return;

            // Display results
            MessageBox.Show(owner, 
                String.Join(Environment.NewLine, dataDialog.NodeElements.Select(element => element.ToString())));
        }
    }
}

# This example shows how to let the user browse for multiple OPC-UA data nodes (data variables or properties).

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System.Windows.Forms import *
from OpcLabs.EasyOpc.UA.Forms.Browsing import *


dataDialog = UADataDialog()
dataDialog.EndpointDescriptor.UrlString = 'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer'
# or 'http://opcua.demo-this.com:51211/UA/SampleServer' (currently not supported)
# or 'https://opcua.demo-this.com:51212/UA/SampleServer/'
dataDialog.MultiSelect = True
dataDialog.UserPickEndpoint = True

dialogResult = dataDialog.ShowDialog()
print(dialogResult)
if dialogResult != DialogResult.OK:
    exit()

# Display results.
for nodeElement in dataDialog.NodeElements:
    print(nodeElement)

print()
print('Finished.')

Advanced

If you want to change the parameters of the client object the component uses to perform its OPC operations, you can use the ClientSelector Property.