Connects to a server. 更多...
| 导入语句： | import QtOpcUa |
| Since: | QtOpcUa 5.12 |
The main API uses backends to make connections. You have to set the backend before any connection attempt.
import QtOpcUa 5.13 as QtOpcUa QtOpcUa.Connection { backend: "open62541" } Component.onCompleted: { connection.connectToEndpoint("opc.tcp://127.0.0.1:43344"); }
| authenticationInformation : AuthenticationInformation |
Set the authentication information to this connection. The authentication information has to be set before calling connectToEndpoint . If no authentication information is set, the anonymous mode will be used. It has no effect on the current connection. If the client is disconnected and then reconnected, the new credentials are used. Reading and writing this property before a backend is set, writes are ignored and reads return and invalid AuthenticationInformation .
| [read-only] availableBackends : stringlist |
Returns the names of all available backends as a list. These are used to select a backend when connecting.
另请参阅 Connection::backend .
| backend : string |
Set the backend to use for a connection to the server. Has to be set before any connection attempt.
另请参阅 Connection::availableBackends .
| [read-only] connected : bool |
Status of the connection.
true
when there is a connection, otherwise
false
.
| [since 5.13] connection : QOpcUaClient |
This property is used only to inject a connection from C++. In case of complex setup of a connection you can use C++ to handle all the details. After the connection is established it can be handed to QML using this property. Ownership of the client is transferred to QML.
class MyClass : public QObject { Q_OBJECT Q_PROPERTY(QOpcUaClient* connection READ connection NOTIFY connectionChanged) public: MyClass (QObject* parent = nullptr); QOpcUaClient *connection() const; signals: void connectionChanged(QOpcUaClient *);
Emitting the signal
connectionChanged
when the client setup is completed, the QML code below will use the connection.
import QtOpcUa 5.13 as QtOpcUa MyClass { id: myclass } QtOpcUa.Connection { connection: myclass.connection }
该特性在 Qt 5.13 引入。
| [since 5.13] currentEndpoint : QOpcUaEndpointDescription |
An endpoint description of the server to which the connection is connected to. When the connection is not established, an empty endpoint description is returned.
该特性在 Qt 5.13 引入。
| defaultConnection : bool |
Makes this the default connection. Usually each node needs to be given a connection to use. If this property is set to
true
, this connection will be used in all cases where a node has no connection set. Already established connections are not affected. If
defaultConnection
被设为
true
on multiple connection the last one is used.
QtOpcUa.Connection { ... defaultConnection: true ... }
另请参阅 Node .
| [read-only] namespaces : stringlist |
List of strings of all namespace URIs registered on the connected server.
| [since 5.13] supportedSecurityPolicies : stringlist |
A list of strings containing the supported security policies
This property is currently available as a Technology Preview, and therefore the API and functionality provided may be subject to change at any time without prior notice.
该特性在 Qt 5.13 引入。
| [since 5.13] supportedUserTokenTypes : array [ tokenTypes ] |
An array of user token policy types of all supported user token types.
This property is currently available as a Technology Preview, and therefore the API and functionality provided may be subject to change at any time without prior notice.
该特性在 Qt 5.13 引入。
| nodeChanged () |
Emitted when the underlying node has changed. This happens when the namespace or identifier of the NodeId 改变。
注意：
相应处理程序是
onNodeChanged
.
[since 5.13]
readNodeAttributesFinished
(
readResults
)
|
Emitted when the read request, started using readNodeAttributes() , is finished. The readResults parameter is an array of ReadResult entries, containing the values requested from the server.
connection.onReadNodeAttributesFinished(results) { for (var i = 0; results.length; i++) { if (results[i].status.isGood) { console.log(results[i].value); } else { // handle error } } }
注意：
相应处理程序是
onReadNodeAttributesFinished
.
This signal was introduced in Qt 5.13.
另请参阅 readNodeAttributes() and ReadResult .
[since 5.13]
writeNodeAttributesFinished
(
writeResults
)
|
Emitted when the write request started using writeNodeAttributes() is finished. The writeResults parameter is an array of WriteResult entries, containing the values requested from the server.
for (var i = 0; i < writeResults.length; i++) { console.log(writeResults[i].nodeId); console.log(writeResults[i].namespaceName); console.log(writeResults[i].attribute); if (writeResults[i].status.isBad) { // value was not written } }
注意：
相应处理程序是
onWriteNodeAttributesFinished
.
This signal was introduced in Qt 5.13.
另请参阅 writeNodeAttributes() and WriteResult .
| connectToEndpoint ( endpointDescription ) |
Connects to the endpoint specified with endpointDescription .
另请参阅 EndpointDescription .
| disconnectFromEndpoint () |
Disconnects an established connection.
| readNodeAttributes ( valuesToBeRead ) |
This function is used to read multiple values from a server in one go. Returns
true
if the read request was dispatched successfully.
valuesToBeRead parameter must be a JavaScript array of ReadItem 条目。
// List of items to read var readItemList = []; // Item to be added to the list of items to be read var readItem; // Prepare an item to be read // Create a new read item and fill properties readItem = QtOpcUa.ReadItem.create(); readItem.ns = "http://qt-project.org"; readItem.nodeId = "s=Demo.Static.Scalar.Double"; readItem.attribute = QtOpcUa.Constants.NodeAttribute.DisplayName; // Add the prepared item to the list of items to be read readItemList.push(readItem); // Add further items [...] if (!connection.readNodeAttributes(readItemList)) { // handle error }
The result of the read request are provided by the signal readNodeAttributesFinished() .
另请参阅 readNodeAttributesFinished() and ReadItem .
| writeNodeAttributes ( valuesToBeWritten ) |
This function is used to write multiple values to a server in one go. Returns
true
if the write request was dispatched successfully.
valuesToBeWritten parameter must be a JavaScript array of WriteItem 条目。
// List of items to write var writeItemList = []; // Item to be added to the list of items to be written var writeItem; // Prepare an item to be written // Create a new write item and fill properties writeItem = QtOpcUa.WriteItem.create(); writeItem.ns = "http://qt-project.org"; writeItem.nodeId = "s=Demo.Static.Scalar.Double"; writeItem.attribute = QtOpcUa.Constants.NodeAttribute.Value; writeItem.value = 32.1; writeItem.valueType = QtOpcUa.Constants.Double; // Add the prepared item to the list of items to be written writeItemList.push(writeItem); // Add further items [...] if (!connection.writeNodeAttributes(writeItemList)) { // handle error }
The result of the write request are provided by the signal Connection::writeNodeAttributesFinished() .
另请参阅 Connection::writeNodeAttributesFinished() and WriteItem .
