gOPCUAConnector.gAsyncReadItems Method

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Used to read values of OPC Nodes asynchronously.

This method does not freeze your application like a synchronous method.

And because this is an asynchronous method, results comes with an event: gAsyncReadItemsCompleted


VB syntax

gOPCUAConnector.gAsyncReadItems(itemsToRead() As gOPCUAReadWriteObject, transactionID As String)


C# syntax

gOPCUAConnector.gAsyncReadItems(gOPCUAReadWriteObject[] itemsToRead, string transactionID)




Array of ReadWriteObjects that holds OPC NodeIDs that you want to read values of them.



Transaction id is ID of asynchronous operation, a unique string.

Used in gAsyncReadItemsCompleted  event or to cancel asynchronous operation.



Return Type




C# code example



                //Step1: Create an array of read write objects and assign ItemIDs

                GelecekCommon.gOPCUAReadWriteObject[] read_write_objects = new GelecekCommon.gOPCUAReadWriteObject[2];

                read_write_objects[0] = new GelecekCommon.gOPCUAReadWriteObject();

                read_write_objects[0].NodeID = txtNodeID1.Text; 


                read_write_objects[1] = new GelecekCommon.gOPCUAReadWriteObject();

                read_write_objects[1].NodeID = txtNodeID2.Text;


                //Step2: Run gAsyncReadItems method  

                GelecekCommon.gOPCUAStatusCode function_result = gOPCUAConnector1.gAsyncReadItems(read_write_objects, txtTransactionID.Text);


                //Step3: Check function result. For a successfull read, function result should be "Good"

                txtFunctionResult.Text = function_result.ToString();



            catch (Exception ex)