以下是将以上全部接口封装在一个类中的示例代码：

#include <open62541/client.h>

class OPCUAClient {
public:
    OPCUAClient() {
        client = UA_Client_new();
        subscriptionId = 0;
    }

    ~OPCUAClient() {
        if (client) {
            UA_Client_delete(client);
        }
    }

    bool connect(const char* url) {
        UA_StatusCode status = UA_Client_connect(client, url);
        return status == UA_STATUSCODE_GOOD;
    }

    bool disconnect() {
        UA_Client_disconnect(client);
        return true;
    }

    bool readValueAttribute(UA_NodeId nodeId, void* value) {
        UA_ReadValueId readValueId;
        readValueId.nodeId = nodeId;
        readValueId.attributeId = UA_ATTRIBUTEID_VALUE;

        UA_ReadRequest request;
        request.nodesToRead = &readValueId;
        request.nodesToReadSize = 1;

        UA_ReadResponse response = UA_Client_Service_read(client, request);

        if (response.responseHeader.serviceResult == UA_STATUSCODE_GOOD &&
            response.resultsSize > 0 && response.results[0].hasValue &&
            response.results[0].value.hasValue)
        {
            *(static_cast<UA_Int32*>(value)) =
                *static_cast<const UA_Int32*>(response.results[0].value.data);
            return true;
        }

       return false;
   }

   bool writeValueAttribute(UA_NodeId nodeId, const void* value) {
       UA_WriteValue writeValue;
       writeValue.nodeId = nodeId;
       writeValue.attributeId = UA_ATTRIBUTEID_VALUE;

       // Set the value to be written
       writeValue.value.hasValue = true;
       writeValue.value.value.type = &UA_TYPES[UA_TYPES_INT32];
       writeValue.value.value.data = const_cast<void*>(value);

       UA_WriteRequest request;
       request.nodesToWrite = &writeValue;
       request.nodesToWriteSize = 1;

       UA_WriteResponse response = UA_Client_Service_write(client, request);
       return response.responseHeader.serviceResult == UA_STATUSCODE_GOOD;
   }

   bool addVariableNode(const char* nodeUri, const char* parentNodeUri) {
       // TODO: Implement the logic to add a variable node
       return false;
   }

   bool deleteNode(const char* nodeUri) {
        // TODO: Implement the logic to delete a node
        return false;
    }

    bool readValueAttributeAsync(UA_NodeId nodeId, void* value) {
        // TODO: Implement the logic to asynchronously read value attribute
        return false;
    }

    bool writeValueAttributeAsync(UA_NodeId nodeId, const void* value) {
        // TODO: Implement the logic to asynchronously write value attribute
        return false;
    }

    bool createSubscription(UA_CreateSubscriptionRequest subscriptionReq) {
        UA_CreateSubscriptionResponse subscriptionRes =
            UA_Client_Subscriptions_create(client, subscriptionReq);

        if (subscriptionRes.responseHeader.serviceResult == UA_STATUSCODE_GOOD) {
            subscriptionId = subscriptionRes.subscriptionId;
            return true;
        }
        
        return false;
    }

    bool deleteSubscription() {
         if (subscriptionId > 0) {
             UA_StatusCoce status = 
                 UA_Client_Subscriptions_delete(client, subscriptionId);
             if (status == UA_STATUSCODE_GOOD) {
                 subscriptionId = 0; // Reset the subscription ID
                 return true;
             }
         }
         
         return false;
     }

     bool createMonitoredItem(UA_MonitoredItemCreateRequest itemReq) {
         // TODO: Implement the logic to create a monitored item
         return false;
     }

     // Add more member functions for other APIs

private:
    UA_Client* client;
    uint32_t subscriptionId; 

};

int main() {
    OPCUAClient client;

    // Connect to the OPC UA server
    if (client.connect("opc.tcp://localhost:4840")) {
        // Read value attribute
        UA_NodeId nodeId = UA_NODEID_NUMERIC(1, 1001);
        UA_Int32 value;
        if (client.readValueAttribute(nodeId, &value)) {
            // Do something with the value
            printf("Value: %d\n", value);
        } else {
            printf("Failed to read value attribute.\n");
        }

        // Write value attribute
        UA_Int32 newValue = 42;
        if (client.writeValueAttribute(nodeId, &newValue)) {
            printf("Value written successfully.\n");
        } else {
            printf("Failed to write value attribute.\n");
        }

        // Disconnect from the OPC UA server
        client.disconnect();
    } else {
        printf("Failed to connect to OPC UA server.\n");
    }

    return 0;
}

请注意，上述代码仅为示例，并未完整实现所有接口的封装逻辑。具体的实现取决于你所使用的 OPC UA 客户端库和需求。


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