Hello,
I admin that I still do not understand where is the problematic point, since you said you already have HMI screens, and I do not see any substantial difference from that - you call methods to read the OPC data, and then use that data to create the Web page markup. You either want something very simple, or something wquite special, but I do not know what it is.
I was thinking how I can help you, and decided to send you a simple application that reads some OPC variable, and displays them in a DataGrid. The whole project is attached to this post; here is the relevant part of it:

class Row
{
public string ItemId { get; set; }
public string Value { get; set; }
}

protected void Page_Load(object sender, EventArgs e)
{
var client = new EasyDAClient();
var itemDescriptors = new DAItemDescriptor[]
{
"Simulation.Register_BOOL",
"Simulation.Register_I2",
"Demo.Ramp",
"Demo.Single"
};

ValueResult[] valueResults = client.ReadMultipleItemValues("OPCLabs.KitServer.2", itemDescriptors);

var data = new List<Row>();
for (int i = 0; i < itemDescriptors.Length; i++)
data.Add(new Row
{
ItemId = itemDescriptors.ItemId,
Value = valueResults.Value.ToString()
});

GridView1.DataSource = data;
GridView1.DataBind();
}

You can see that we are reading some values, and then use the result to construct a data source for the grid. The resulting page looks e.g. like this:



ItemIdValue

Simulation.Register_BOOLFalse

Simulation.Register_I20

Demo.Ramp-6.16515159606934

Demo.Single-6.1339




I thought that we can now start modifying this example to achieve what you need. You can replace the server and Item IDs with those that you need. If they are all bool values indicating which alarm is active, and you only want to fill in the grid with active alarms, you can put in an 'if-then' statement and only put into the list the active alarms. And so on-and if you do not know how to do something, you can ask concrete question. Otherwise, I am left guessing where your problem really is.
Best regards,
DataGridWebApplication.zip

Regarding bullet 1), I assume you are OK with filling in the data when the page loads, and then you somehow reload (refresh) the page when you need new updated data? Or how do you do it in your HMI screens? I guess we'd like to keep the same approach.
Is there a special requirement to use ASP.NET grid view, or why cannot you just generate HTML table with the data?
Thanks

Hello,
I am sorry but I do not understand this part:

I need only fill this gridview with active alarms coming from my PLC for viewing only, but I can not see a way to retrieve the objects coming from the OPC carry methods within this gridview.

Can you please re-phrase it differently, and possibly in more detail? It seems to me that you can just call e.g. ReadMultipleItems, filter the results that signify active alarms, and put them into the grid.

Hello,
yes, I meant to use the State parameter as you indicated. But whether that's actually the right suggestion, we need to figure out yet. Before your latest reply, I have not realized/aware that you are writing an ASP.NET application, and that may change some things.
I think I need to know a bit more about the structure of your application in order to answer the rest. What have you achieved so far? Do you have an ASP.NET GridView filled in with OPC item values when the page is generated? If so, wouldn't it be more appropriate to simply use "reads" (e.g. ReadItem, ReadMultipleItems), since the subscriptions can only update some "background" value on the server, but will not be immediately sent to the client browser anyway?
I am also a bit confused about your last paragraph - is there just a single OPC-DA tag that acknolwedges all active alarms? If so, you can have a button or something that in turn sets this tag to acknowledge all alarms, and for this purpose, you wil not need to know which active alarm tag it corresponds to. Can you clarify this?
Best regards

I apologize for delay-I am on travel, will reply by Monday.