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  7. How to subscribe to multiple OPC DA items, when amount of variables is changing?
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How to subscribe to multiple OPC DA items, when amount of variables is changing?

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20 Dec 2023 12:02 #12493 by mut9bu
Replied by mut9bu on topic How to subscribe to multiple OPC DA items, when amount of variables is changing?
Yes exactly :-)
The following user(s) said Thank You: support

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20 Dec 2023 11:28 #12492 by support
Replied by support on topic How to subscribe to multiple OPC DA items, when amount of variables is changing?
Hello.
It seems to me that you can simply do
client.SubscribeMultipleItems(dAItemGroupArguments .ToArray());
Is that what you were looking for?
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20 Dec 2023 10:54 - 20 Dec 2023 11:13 #12491 by mut9bu
Replied by mut9bu on topic How to subscribe to multiple OPC DA items, when amount of variables is changing?
Hello

My console app has following arguments:
        public string ip_address = Environment.GetCommandLineArgs()[1];
        public string item_no = Environment.GetCommandLineArgs()[2];        
        public string item_1 = Environment.GetCommandLineArgs()[3];
        public string item_2 = Environment.GetCommandLineArgs()[4];
        public string item_3 = Environment.GetCommandLineArgs()[5];
        public string item_4 = Environment.GetCommandLineArgs()[6];
        public string item_5 = Environment.GetCommandLineArgs()7];
        public string item_6 = Environment.GetCommandLineArgs()[8];
        public string item_7 = Environment.GetCommandLineArgs()[9];
        public string item_8 = Environment.GetCommandLineArgs()[10];
        public string item_9 = Environment.GetCommandLineArgs()[11];
        public string item_10 = Environment.GetCommandLineArgs()[12];

Due to the item_no parameter I tried to define a list of items:
         List<DAItemGroupArguments> dAItemGroupArguments = new List<DAItemGroupArguments>();
 
         public void item_list()
         {
           for(int i = 0; i < Convert.ToInt16(item_no); i++)
            {
                dAItemGroupArguments.Add(new DAItemGroupArguments(ip, server, Environment.GetCommandLineArgs()[i+3], 1000, null));
            }
         }

So I should use always this list (or something similar) in the client.SubscribeMultipleItems(...) expression.
Last edit: 20 Dec 2023 11:13 by support.

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20 Dec 2023 10:42 #12490 by support
Replied by support on topic How to subscribe to multiple OPC DA items, when amount of variables is changing?
Hello.

It's easy to do. You just need to convert what you have into the form expected by the method. But I cannot answer it without knowing in which form (object types, their properties etc.) you get your items. Please share a piece of code illustrating that.

Regards

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20 Dec 2023 10:27 - 20 Dec 2023 10:40 #12489 by mut9bu
How to subscribe to multiple OPC DA items, when amount of variables is changing? was created by mut9bu
Hello

In my C# .net framework 4.7.2 app I am subscribing to multiple OPC DA items. But my app is called from a parent app with arguments. That means, the number of items and the item definitions come from the argument parameters and changing each time.

Normally I subscribe to 3 items with following code. How should I modify my code, so that I can sometimes for example subscribe to 2 items sometimes to 8 items , depending on the argument parameters? With other words I would like to use a List of items for the client.SubscribeMultipleItems expression. But couldn't find the correct way for this.
using (var client = new EasyDAClient())
            {
                client.ItemChanged += client_Main1_ItemChanged;
                client.SubscribeMultipleItems(
                    new[] {
                            new DAItemGroupArguments(ip, "OPC.IwSCP.1",item_def1, 1000, null),
                            new DAItemGroupArguments(ip, "OPC.IwSCP.1",item_def2, 1000, null),
                            new DAItemGroupArguments(ip, "OPC.IwSCP.1",item_def3, 1000, null),
                        }                    
                    );
            }
 
public void client_Main1_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        {
            if (e.Succeeded)
            {
                item_value = e.Vtq.ToString();
            }
            //
            else
            {
                Console.WriteLine($"{e.ErrorMessageBrief}");
            }
         }
Last edit: 20 Dec 2023 10:40 by support.

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