Qt OPC UA Viewer Example

 // Copyright (C) 2018 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

 #include "opcuamodel.h"
 #include "treeitem.h"
 #include <QOpcUaClient>
 #include <QOpcUaNode>
 #include <QIcon>

 OpcUaModel::OpcUaModel(QObject *parent) : QAbstractItemModel(parent)
 {
 }

 void OpcUaModel::setOpcUaClient(QOpcUaClient *client)
 {
     beginResetModel();
     mOpcUaClient = client;
     if (mOpcUaClient)
         mRootItem.reset(new TreeItem(client->node("ns=0;i=84"), this /* model */, nullptr /* parent */));
     else
         mRootItem.reset(nullptr);
     endResetModel();
 }

 QOpcUaClient *OpcUaModel::opcUaClient() const
 {
     return mOpcUaClient;
 }

 QVariant OpcUaModel::data(const QModelIndex &index, int role) const
 {
     if (!index.isValid())
         return QVariant();

     auto item = static_cast<TreeItem *>(index.internalPointer());

     switch (role) {
     case Qt::DisplayRole:
         return item->data(index.column());
     case Qt::DecorationRole:
         if (index.column() == 0)
             return item->icon(index.column());
         break;
     default:
         break;
     }

     return QVariant();
 }

 QVariant OpcUaModel::headerData(int section, Qt::Orientation orientation, int role) const
 {
     if (role != Qt::DisplayRole)
         return QVariant();

     if (orientation == Qt::Vertical)
         return QStringLiteral("Row %1").arg(section);

     switch (section) {
     case 0:
         return QStringLiteral("BrowseName");
     case 1:
         return QStringLiteral("Value");
     case 2:
         return QStringLiteral("NodeClass");
     case 3:
         return QStringLiteral("DataType");
     case 4:
         return QStringLiteral("NodeId");
     case 5:
         return QStringLiteral("DisplayName");
     case 6:
         return QStringLiteral("Description");
     case 7:
         return QStringLiteral("Historizing");
     default:
         break;
     }
     return QStringLiteral("Column %1").arg(section);
 }

 QModelIndex OpcUaModel::index(int row, int column, const QModelIndex &parent) const
 {
     if (!hasIndex(row, column, parent))
         return QModelIndex();

     TreeItem *item = parent.isValid()
         ? static_cast<TreeItem*>(parent.internalPointer())->child(row)
         : mRootItem.get();

     return item ? createIndex(row, column, item) : QModelIndex();
 }

 QModelIndex OpcUaModel::parent(const QModelIndex &index) const
 {
     if (!index.isValid())
         return QModelIndex();

     auto childItem = static_cast<TreeItem*>(index.internalPointer());
     auto parentItem = childItem->parentItem();

     if (childItem == mRootItem.get() || !parentItem)
         return QModelIndex();

     return createIndex(parentItem->row(), 0, parentItem);
 }

 int OpcUaModel::rowCount(const QModelIndex &parent) const
 {

     if (!mOpcUaClient)
         return 0;

     if (parent.column() > 0)
         return 0;

     if (!parent.isValid())
         return 1; // only one root item

     auto parentItem = static_cast<TreeItem*>(parent.internalPointer());
     return parentItem ? parentItem->childCount() : 0;
 }

 int OpcUaModel::columnCount(const QModelIndex &parent) const
 {
     if (parent.isValid())
         return static_cast<TreeItem*>(parent.internalPointer())->columnCount();
     return mRootItem ? mRootItem->columnCount() : 0;
 }