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Live Binding

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26 Jun 2018 12:24 #6475 by support
Replied by support on topic Live Binding
Thank you. Now with the new full picture I have realized what the problem is.

You are binding to an OPC DA property (Value). OPC DA properties do not support subscriptions, that's why you are not getting any dynamic updates. There are also no other parameters to be configured for Read, Subscribe, or Write, and that's why System.Object is shown.

In order to achieve what you want, you need to bind to the OPC item itself. That is, when you are in the "Point Editor", you need to select the node that, in the information pane at the bottom of window, will say "OPC-DA Node", and *not* "OPC-DA Property". The properties also have a different icon, and are always shown as terminal leaves in the tree.

I hope this helps.

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26 Jun 2018 12:16 #6473 by CAbrams
Replied by CAbrams on topic Live Binding
initial read works but no error code, error message nor exception is displayed when additional bindings are made for these.

all bindings are readandsubscribe as in attached.

DAConn templates appear to be populated correctly as in attached.



If i create a new win form app and make any bindings all params say system.object as in attached. the only way I was able to have one of my bindings show any different parameters is if I modified one of the bindings in your LiveBindingDemo. This worked one time to display dynamically changing values but I have not been able to make it work subsequently. I am able to subscribe to my point using EasyDAClient and all appears to work properly re: dynamic update. currently we read 10's of points in our app but are in process of making that 100's of points and really like the code free flexibility of live binding for controls that are purely for visualization.

CAbrams
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26 Jun 2018 05:44 #6471 by support
Replied by support on topic Live Binding
Hello,
thanks for clarification. Now I mostly understand the issue.

Here is some information:

- I was able to reproduce the fact that "Write Parameters" show as System.Object. This appears to be a bug on our side. We will have a look at it. It should not have, however, influence on the actual problem you have. I have not seen "System.Object" in other parameters, did you?

- I do not know where the 100 ms comes from, I was not able to reproduce it; the default should be indeed 1000 ms. Please check the "parameters templates" on the daConnectivity1 component (click on it in the component tray below the form, the view its properties). This has the initial values for newly create bindings. Anyway, 100 ms should work too, or you can change it back to 1000 ms if you like.

- Please check "Binding Operation" property on the binding (this is in the same property grid as you have sent the picture of, but a bit higher, so that I cannot see its value in your snapshot). The value should be "ReadAndSubscribe" (and not e.g. just Read).

- If the above is correct, it could be that the Read works, but Subscribe gives some error, but you do not see the error, because in Live Binding, you need to take care of displaying the errors yourself. This is described here: opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...ing%20in%20Live%20Binding.html (at the bottom). Errors are typically displayed by making a second binding with "Argument Path" set to Exception, ErrorMessage or such, but that might be too complicate for now. I suggest that you simply change the "Argument Path" on the existing binding from "Value" to "ErrorMessage", and see if running the project shows any error in the control.

Regards

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25 Jun 2018 11:20 #6468 by CAbrams
Replied by CAbrams on topic Live Binding
I am investigating use of QuickOPC in our app. we currently use EasyDAClient. I opened your LiveBindingDemo and modified one of the text box bind points to reference our KW ProConOS OPC server as attached pointchange.jpg. This works great and I can see the dynamic update of the point value in your LiveMappingDemo app. My issue is that if I place a new textbox on your form and bind another ProConOS point the textbox seems to read once when form is opened but not updating as value changes. what I noticed is that my new textbox with bound point does not have the same read and subscribe parameters as the text box I originally modified. Namely, the read parameter of ByValueAge(1000 ms) and the subscribe parameter of 100ms. these parameters on my new textbox simply say system.object. hope this clarifies my issue.
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24 Jun 2018 18:26 #6465 by support
Replied by support on topic Live Binding
Hello,

unfortunately your post is not clear to me. Please read Rules for Forums Posts ( www.opclabs.com/forum/announcements12/2365-rules-for-forum-posts ) and clarify the information provided.

Best regards

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22 Jun 2018 16:05 #6464 by CAbrams
Live Binding was created by CAbrams
I'm using LiveBinding Demo and can bind to my server and can see value updates only when the the read and subscribe parameters have values other than system.object. I can not seem to bind to a point and change these parameters? please advise.

CA

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