Examples - User Interface - Use selection descriptors in OPC UA generic browsing dialog

.NET

C#
Python (.NET)

// This example shows how the current node and selected nodes can be persisted between dialog invocations.

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

namespace UAFormsDocExamples._UABrowseDialog
{
    static partial class ShowDialog
    {
        public static void SelectionDescriptors(IWin32Window owner)
        {
            // The variables that persist the current and selected nodes.

            var currentNodeDescriptor = new UABrowseNodeDescriptor();
            var selectionDescriptors = new UABrowseNodeDescriptorCollection();

            // The initial current node (optional).

            currentNodeDescriptor.EndpointDescriptor = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";

            // Repeatedly show the dialog until the user cancels it.

            do
            {
                var browseDialog = new UABrowseDialog();
                browseDialog.Mode.MultiSelect = true;

                // Set the dialog inputs from the persistence variables.

                browseDialog.InputsOutputs.CurrentNodeDescriptor = currentNodeDescriptor;
                browseDialog.InputsOutputs.SelectionDescriptors.Clear();
                foreach (UABrowseNodeDescriptor browseNodeDescriptor in selectionDescriptors)
                    browseDialog.InputsOutputs.SelectionDescriptors.Add(browseNodeDescriptor);

                DialogResult dialogResult = browseDialog.ShowDialog(owner);
                if (dialogResult != DialogResult.OK)
                    break;

                // Update the persistence variables with the dialog output.

                currentNodeDescriptor = browseDialog.InputsOutputs.CurrentNodeDescriptor;
                selectionDescriptors.Clear();
                foreach (UABrowseNodeDescriptor browseNodeDescriptor in browseDialog.InputsOutputs.SelectionDescriptors)
                    selectionDescriptors.Add(browseNodeDescriptor);

            } while (true);
        }
    }
}

# This example shows how the current node and selected nodes can be persisted between dialog invocations.

# 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 import *
from OpcLabs.EasyOpc.UA.Forms.Browsing import *


# The variables that persist the current and selected nodes.
currentNodeDescriptor = UABrowseNodeDescriptor()
selectionDescriptors = UABrowseNodeDescriptorCollection()

# The initial current node (optional).

currentNodeDescriptor.EndpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer')

# Repeatedly show the dialog until the user cancels it.

while True:
    browseDialog = UABrowseDialog()
    browseDialog.Mode.MultiSelect = True

    # Set the dialog inputs from the persistence variables.

    browseDialog.InputsOutputs.CurrentNodeDescriptor = currentNodeDescriptor
    browseDialog.InputsOutputs.SelectionDescriptors.Clear()
    for browseNodeDescriptor in selectionDescriptors:
        browseDialog.InputsOutputs.SelectionDescriptors.Add(browseNodeDescriptor)

    dialogResult = browseDialog.ShowDialog()
    print(dialogResult)
    if dialogResult != DialogResult.OK:
        break

    # Update the persistence variables with the dialog output.

    currentNodeDescriptor = browseDialog.InputsOutputs.CurrentNodeDescriptor
    selectionDescriptors.Clear()
    for browseNodeDescriptor in browseDialog.InputsOutputs.SelectionDescriptors:
        selectionDescriptors.Add(browseNodeDescriptor)

print('Finished.')

COM

VBScript

Rem This example shows how the current node and selected nodes can be persisted between dialog invocations.

Option Explicit

Const DialogResult_OK = 1

' The variables that persist the current and selected nodes.

Dim CurrentNodeDescriptor: Set CurrentNodeDescriptor = CreateObject("OpcLabs.EasyOpc.UA.Forms.Browsing.UABrowseNodeDescriptor")
Dim SelectionDescriptors: Set SelectionDescriptors = CreateObject("OpcLabs.EasyOpc.UA.Forms.Browsing.UABrowseNodeDescriptorCollection")

' The initial current node (optional).

CurrentNodeDescriptor.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"

' Repeatedly show the dialog until the user cancels it.

Do
    Dim BrowseDialog: Set BrowseDialog = CreateObject("OpcLabs.EasyOpc.UA.Forms.Browsing.UABrowseDialog")
    BrowseDialog.Mode.MultiSelect = True

    ' Set the dialog inputs from the persistence variables.

    Set BrowseDialog.InputsOutputs.CurrentNodeDescriptor = CurrentNodeDescriptor
    BrowseDialog.InputsOutputs.SelectionDescriptors.Clear
    Dim BrowseNodeDescriptor: For Each BrowseNodeDescriptor In SelectionDescriptors
        BrowseDialog.InputsOutputs.SelectionDescriptors.Add BrowseNodeDescriptor
    Next

    Dim dialogResult1: dialogResult1 = BrowseDialog.ShowDialog
    If dialogResult1 <> DialogResult_OK Then
        Exit Do
    End If

    ' Update the persistence variables with the dialog output.

    Set CurrentNodeDescriptor = BrowseDialog.InputsOutputs.CurrentNodeDescriptor
    selectionDescriptors.Clear
    For Each BrowseNodeDescriptor In BrowseDialog.InputsOutputs.SelectionDescriptors
        SelectionDescriptors.Add BrowseNodeDescriptor
    Next

Loop While True

Conceptual

Generic OPC-UA Browsing Dialog