Installed Examples - Web - DataGridWebApplication

Demonstrates how easily can WebControls.GridView be populated with data read from OPC Data Access server.

The default page code-behind:

C#
VB.NET

// $Header: $
// Copyright (c) CODE Consulting and Development, s.r.o., Plzen. All rights reserved.

// ReSharper disable ArrangeModifiersOrder
// ReSharper disable InconsistentNaming
// ReSharper disable UnusedAutoPropertyAccessor.Local

// DataGridWebApplication: Demonstrates how easily can GridView be populated with data read from OPC Data Access server.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using System.Collections.Generic;
using OpcLabs.BaseLib.OperationModel;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.Extensions;

namespace DataGridWebApplication
{
    public partial class _Default : System.Web.UI.Page
    {
        class Row
        {
            public string ItemId { get; set; }
            public string Value { get; set; }
        }

        static _Default()
        {
            // Enable auto-subscribing optimization (not necessary), which can improve performance with repeated Read requests.
            Client.TryEnableAutoSubscribingOptimization();
        }

        // Use a shared client instance to allow for better optimization.
        static private readonly EasyDAClient Client = new EasyDAClient();

        protected void Page_Load(object sender, EventArgs e)
        {
            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[i].ItemId, 
                        Value = valueResults[i].Value?.ToString()
                    });

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

' DataGridWebApplication: Demonstrates how easily can GridView be populated with data read from OPC Data Access server.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.BaseLib.OperationModel
Imports OpcLabs.EasyOpc.DataAccess.Extensions

' ReSharper disable InconsistentNaming

Partial Public Class _Default
    Inherits UI.Page

    Private Class Row
        Public Property ItemId As String

        Public Property Value As String
    End Class

    Shared Sub New()
        ' Enable auto-subscribing optimization (not necessary), which can improve performance with repeated Read requests.
        Client.TryEnableAutoSubscribingOptimization()
    End Sub

    ' Use a shared client instance to allow for better optimization.
    Shared ReadOnly Client As New EasyDAClient

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim itemDescriptors = New DAItemDescriptor() {"Simulation.Register_BOOL", "Simulation.Register_I2", "Demo.Ramp", "Demo.Single"}

        Dim valueResults() As ValueResult = Client.ReadMultipleItemValues("OPCLabs.KitServer.2", itemDescriptors)

        Dim data = New List(Of Row)()
        For i As Integer = 0 To itemDescriptors.Length - 1
            data.Add(New Row With {.ItemId = itemDescriptors(i).ItemId, .Value = valueResults(i).Value.ToString()})
        Next i

        GridView1.DataSource = data
        GridView1.DataBind()
    End Sub
End Class

Conceptual

Examples for OPC “Classic” (OPC-DA, OPC XML-DA and OPC-A&E)

Reading just the value (OPC Classic)