In This Topic

General

Icon:

With UAHostAndEndpointDialog, your application can integrate a dialog box from which the user can select a host (computer) and an endpoint of OPC-UA server residing on it. This dialog box combines functions of the Computer Browser Dialog and OPC-UA Endpoint Dialog - into a single dialog.

In addition, the user can add Host nodes in case the particular computer is not visible on the network, or add OPC-UA Endpoint nodes in case the OPC_UA Server is known to exist but is not returned by OPC-UA discovery feature.

Here is an example of OPC-UA Host and Endpoint dialog in action:

.NET

// This example shows how to let the user browse for a host (computer) and an endpoint of an OPC-UA server residing on it.

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

namespace UAFormsDocExamples._UAHostAndEndpointDialog
{
    static class ShowDialog
    {
        public static void Main1(IWin32Window owner)
        {
            var hostAndEndpointDialog = new UAHostAndEndpointDialog
            {
                EndpointDescriptor = {Host = "opcua.demo-this.com"}
            };

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

            // Display results
            MessageBox.Show(owner, 
                $"HostElement: {hostAndEndpointDialog.HostElement}\r\n" +
                $"DiscoveryElement: {hostAndEndpointDialog.DiscoveryElement}");
        }
    }
}

# This example shows how to let the user browse for a host (computer) and
# an endpoint of an OPC-UA server residing on it.

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.
$hostAndEndpointDialog = New-Object UAHostAndEndpointDialog
$hostAndEndpointDialog.EndpointDescriptor.Host = "opcua.demo-this.com"

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

# Display results
$hostElement = $hostAndEndpointDialog.HostElement
if ($hostElement -ne $null) {
    Write-Host "HostElement: $($hostElement)"
}
$discoveryElement = $hostAndEndpointDialog.DiscoveryElement
if ($discoveryElement -ne $null) {
    Write-Host "DiscoveryElement: $($discoveryElement)"
}

# This example shows how to let the user browse for a host (computer) and an endpoint of an OPC-UA server residing on it.

# 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 *


hostAndEndpointDialog = UAHostAndEndpointDialog()
hostAndEndpointDialog.EndpointDescriptor.Host = 'opcua.demo-this.com'

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

# Display results.
print('HostElement: ', hostAndEndpointDialog.HostElement, sep='')
print('DiscoveryElement: ', hostAndEndpointDialog.DiscoveryElement, sep='')

print('Finished.')

COM

// This example shows how to let the user browse for a host (computer) and an endpoint of an OPC-UA server residing on it.

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

namespace _UAHostAndEndpointDialog
{
    void ShowDialog::Main()
    {
        // Initialize the COM library
        CoInitializeEx(NULL, COINIT_MULTITHREADED);
        {
            // 
            _UAHostAndEndpointDialogPtr HostAndEndpointDialogPtr(__uuidof(UAHostAndEndpointDialog));

            //
            HostAndEndpointDialogPtr->EndpointDescriptor->Host = L"opcua.demo-this.com";

            // 
            DialogResult dialogResult = HostAndEndpointDialogPtr->ShowDialog(NULL);
            _tprintf(_T("%d\n"), dialogResult);

            if (dialogResult == 1/*OK*/)
            {
                // Display results
                _HostElementPtr hostElementPtr = HostAndEndpointDialogPtr->HostElement;
                _tprintf(_T("HostElement: %s\n"), (hostElementPtr == NULL) ? _T("") : (LPCTSTR)CW2CT(hostElementPtr->ToString));
                _UADiscoveryElementPtr discoveryElementPtr = HostAndEndpointDialogPtr->DiscoveryElement;
                _tprintf(_T("DiscoveryElement: %s\n"), (discoveryElementPtr == NULL) ? _T("") : (LPCTSTR)CW2CT(discoveryElementPtr->ToString));
            }
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

// This example shows how to let the user browse for a host (computer) and
// an endpoint of an OPC-UA server residing on it.

class procedure ShowDialog.Main;
var
  HostAndEndpointDialog: UAHostAndEndpointDialog;
begin
  // Instantiate the dialog object
  HostAndEndpointDialog := CoUAHostAndEndpointDialog.Create;

  HostAndEndpointDialog.EndpointDescriptor.Host := 'opcua.demo-this.com';

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

  // Display results
  // IMPROVE: check the nullness of HostAndEndpointDialog.HostElement
  WriteLn('HostElement: ', HostAndEndpointDialog.HostElement.ToString);
  // IMPROVE: check the nullness of HostAndEndpointDialog.DiscoveryElement
  WriteLn('DiscoveryElement: ', HostAndEndpointDialog.DiscoveryElement.ToString);
end;

// This example shows how to let the user browse for a host (computer) and
// an endpoint of an OPC-UA server residing on it.

class procedure ShowDialog.Main;
var
  HostAndEndpointDialog: OpcLabs_EasyOpcForms_TLB._UAHostAndEndpointDialog;
  DialogResult: System_Windows_Forms_TLB.DialogResult;
  HostElement: OpcLabs_BaseLib_TLB.HostElement;
  DiscoveryElement: OpcLabs_EasyOpcUA_TLB.UADiscoveryElement;
begin
  // Instantiate the dialog object
  HostAndEndpointDialog := CoUAHostAndEndpointDialog.Create;

  HostAndEndpointDialog.EndpointDescriptor.Host := 'opcua.demo-this.com';

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

  if DialogResult <> DialogResult_OK then
    Exit;

  // Display results
  HostElement := HostAndEndpointDialog.HostElement;
  if HostElement <> nil then
    WriteLn('HostElement: ', HostElement.ToString);
  DiscoveryElement := HostAndEndpointDialog.DiscoveryElement;
  if DiscoveryElement <> nil then
    WriteLn('DiscoveryElement: ', DiscoveryElement.ToString);
end;

Rem This example shows how to let the user browse for a host (computer) and an endpoint of an OPC-UA server residing on it.

Private Sub ShowDialog_Main_Command_Click()
    OutputText = ""

    Dim HostAndEndpointDialog As New UAHostAndEndpointDialog
    HostAndEndpointDialog.endpointDescriptor.Host = "opcua.demo-this.com"
    
    Dim DialogResult
    DialogResult = HostAndEndpointDialog.ShowDialog
    
    OutputText = OutputText & DialogResult & vbCrLf
    If DialogResult <> 1 Then   ' OK
        Exit Sub
    End If
    
    ' Display results
    Dim HostElement As HostElement
    Set HostElement = HostAndEndpointDialog.HostElement
    If Not HostElement Is Nothing Then
        OutputText = OutputText & "HostElement: " & HostElement & vbCrLf
    End If
    Dim DiscoveryElement As UADiscoveryElement
    Set DiscoveryElement = HostAndEndpointDialog.DiscoveryElement
    If Not DiscoveryElement Is Nothing Then
        OutputText = OutputText & "DiscoveryElement: " & DiscoveryElement & vbCrLf
    End If
End Sub

Rem This example shows how to let the user browse for a host (computer) and an endpoint of an OPC-UA server residing on it.

Option Explicit

Const DialogResult_OK = 1

Dim HostAndEndpointDialog: Set HostAndEndpointDialog = CreateObject("OpcLabs.EasyOpc.UA.Forms.Browsing.UAHostAndEndpointDialog")
HostAndEndpointDialog.EndpointDescriptor.Host = "opcua.demo-this.com"

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

If dialogResult <> DialogResult_OK Then
    WScript.Quit
End If

' Display results
WScript.Echo "HostElement: " & HostAndEndpointDialog.HostElement
WScript.Echo "DiscoveryElement: " & HostAndEndpointDialog.DiscoveryElement

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.