Installed Examples - WindowsForms

This is a source of the Demo application for OPC “Classic” that ships with the QuickOPC.NET product. The application shows most product functions, including the browsing forms, OPC property access, and event-based subscriptions.

The main form:

C#
VB.NET

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

using System.Diagnostics;
using EasyOpcNetDemo.Properties;
using JetBrains.Annotations;
using OpcLabs.BaseLib.ComInterop;
using OpcLabs.EasyOpc.DataAccess;
using System;
using System.Globalization;
using System.Reflection;
using System.Windows.Forms;
using OpcLabs.EasyOpc.DataAccess.OperationModel;
using OpcLabs.EasyOpc.OperationModel;

[assembly:CLSCompliant(true)]
namespace EasyOpcNetDemo
{
    public partial class MainForm : Form
    {
        // ReSharper disable once NotNullMemberIsNotInitialized
        public MainForm()
        {
            InitializeComponent();
        }

        // ReSharper disable InconsistentNaming
        private void browseServersButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);

            opcServerDialog1.Location = machineNameTextBox.Text;
            if (opcServerDialog1.ShowDialog(this) == DialogResult.OK)
            {
                Debug.Assert(opcServerDialog1.ServerElement != null);
                serverClassTextBox.Text = opcServerDialog1.ServerElement.ServerClass;
            }
        }

        // ReSharper disable InconsistentNaming
        private void browseItemsButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);
            Debug.Assert(serverClassTextBox.Text != null);

            daItemDialog1.ServerDescriptor.MachineName = machineNameTextBox.Text;
            daItemDialog1.ServerDescriptor.ServerClass = serverClassTextBox.Text;
            if (daItemDialog1.ShowDialog() == DialogResult.OK)
            {
                Debug.Assert(daItemDialog1.NodeElement != null);
                itemIdTextBox.Text = daItemDialog1.NodeElement.ItemId;
            }
        }

        // ReSharper disable InconsistentNaming
        private void readItemButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);
            Debug.Assert(serverClassTextBox.Text != null);
            Debug.Assert(itemIdTextBox.Text != null);

            DAVtq vtq = null;
            Exception exception = null;
            try
            {
                vtq = easyDAClient1.ReadItem(
                    machineNameTextBox.Text,
                    serverClassTextBox.Text,
                    itemIdTextBox.Text);
            }
            catch (OpcException ex)
            {
                exception = ex;
            }
            DisplayVtq(vtq);
            DisplayException(exception);
        }

        private void DisplayVtq(DAVtq vtq)
        {
            if (vtq is null)
            {
                valueTextBox.Text = "";
                timestampTextBox.Text = "";
                qualityTextBox.Text = "";
            }
            else
            {
                valueTextBox.Text = vtq.DisplayValue(); 
                timestampTextBox.Text = vtq.Timestamp.ToString(CultureInfo.CurrentCulture);
                qualityTextBox.Text = vtq.Quality.ToString();
            }
        }

        private void DisplayException(Exception exception)
        {
            exceptionTextBox.Text = (exception is null) ? "" : exception.GetBaseException().Message;
        }

        private bool _isItemSubscribedValue/* = false*/;
        private int _itemHandle/* = 0*/;

        public bool IsItemSubscribed
        {
            get { return _isItemSubscribedValue; }
            set 
            {
                _isItemSubscribedValue = value;
                subscribeItemButton.Enabled = !_isItemSubscribedValue;
                changeItemSubscriptionButton.Enabled = _isItemSubscribedValue;
                unsubscribeItemButton.Enabled = _isItemSubscribedValue;
            }
        }

        // ReSharper disable InconsistentNaming
        private void subscribeItemButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);
            Debug.Assert(serverClassTextBox.Text != null);
            Debug.Assert(itemIdTextBox.Text != null);

            const VarTypes dataType = VarTypes.Empty;
            // ReSharper disable SuggestUseVarKeywordEvident
            int requestedUpdateRate = (int)requestedUpdateRateNumericUpDown.Value;
            float percentDeadband = (float)percentDeadbandNumericUpDown.Value;
            // ReSharper restore SuggestUseVarKeywordEvident
            _itemHandle = easyDAClient1.SubscribeItem(
                machineNameTextBox.Text,
                serverClassTextBox.Text,
                itemIdTextBox.Text, 
                dataType, 
                requestedUpdateRate,
                percentDeadband);
            IsItemSubscribed = true;
        }

        // ReSharper disable InconsistentNaming
        private void changeItemSubscriptionButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            var groupParameters = new DAGroupParameters(
                (int)requestedUpdateRateNumericUpDown.Value, 
                (float)percentDeadbandNumericUpDown.Value);
            easyDAClient1.ChangeItemSubscription(_itemHandle, groupParameters);
        }

        // ReSharper disable InconsistentNaming
        private void unsubscribeItemButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            easyDAClient1.UnsubscribeItem(_itemHandle);
            _itemHandle = 0;
            IsItemSubscribed = false;
        }

        // ReSharper disable InconsistentNaming
        private void easyDAClient1_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        // ReSharper restore InconsistentNaming
        {
            DisplayVtq(e.Vtq);
            DisplayException(e.Exception);
        }

        // ReSharper disable InconsistentNaming
        private void browseMachinesButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            if (computerBrowserDialog1.ShowDialog() == DialogResult.OK)
               machineNameTextBox.Text = computerBrowserDialog1.SelectedName;
        }

        // ReSharper disable InconsistentNaming
        private void aboutButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            MessageBox.Show(this, Assembly.GetExecutingAssembly().FullName, 
                Resources.MainForm_aboutButton_Click_Assembly_Name, MessageBoxButtons.OK, 
                MessageBoxIcon.Information);
        }

        // ReSharper disable InconsistentNaming
        private void browsePropertiesButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);
            Debug.Assert(serverClassTextBox.Text != null);
            Debug.Assert(itemIdTextBox.Text != null);

            daPropertyDialog1.ServerDescriptor.MachineName = machineNameTextBox.Text;
            daPropertyDialog1.ServerDescriptor.ServerClass = serverClassTextBox.Text;
            daPropertyDialog1.NodeDescriptor = itemIdTextBox.Text;
            if (daPropertyDialog1.ShowDialog() == DialogResult.OK)
            {
                Debug.Assert(daPropertyDialog1.PropertyElement != null);
                propertyIdMaskedTextBox.Text = daPropertyDialog1.PropertyElement.PropertyId.ToString();
            }
        }

        // ReSharper disable InconsistentNaming
        private void getPropertyValueButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);
            Debug.Assert(serverClassTextBox.Text != null);
            Debug.Assert(itemIdTextBox.Text != null);

            int propertyId = Convert.ToInt32(propertyIdMaskedTextBox.Text, CultureInfo.CurrentCulture);
            object value = null;
            Exception exception = null;
            try
            {
                value = easyDAClient1.GetPropertyValue(
                    machineNameTextBox.Text,
                    serverClassTextBox.Text,
                    itemIdTextBox.Text,
                    propertyId);
            }
            catch (OpcException ex)
            {
                exception = ex;
            }
            propertyValueTextBox.Text = (value is null ? "(null)" : 
                String.Format(CultureInfo.CurrentCulture, "{0}", value));
            DisplayException(exception);
        }

        // ReSharper disable InconsistentNaming
        private void writeItemValueButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Debug.Assert(machineNameTextBox.Text != null);
            Debug.Assert(serverClassTextBox.Text != null);
            Debug.Assert(itemIdTextBox.Text != null);

            object value = valueToWriteTextBox.Text;
            Exception exception = null;
            try
            {
                easyDAClient1.WriteItemValue(
                    machineNameTextBox.Text, 
                    serverClassTextBox.Text, 
                    itemIdTextBox.Text, 
                    value);
            }
            catch (OpcException ex)
            {
                exception = ex;
            }
            DisplayException(exception);
        }

        // ReSharper disable InconsistentNaming
        private void closeButton_Click(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {
            Close();
        }

        // ReSharper disable InconsistentNaming
        private void MainForm_Load(object sender, EventArgs e)
        // ReSharper restore InconsistentNaming
        {

        }
    }
}

' $Header: $ 
' Copyright (c) CODE Consulting and Development, s.r.o., Plzen. All rights reserved.
Imports OpcLabs.BaseLib.ComInterop
Imports OpcLabs.EasyOpc.DataAccess
Imports System.Globalization
Imports OpcLabs.EasyOpc.OperationModel
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

<Assembly:CLSCompliant(True)>
' ReSharper disable CheckNamespace
Namespace EasyOpcNetDemo
    ' ReSharper restore CheckNamespace

    Partial Public Class MainForm
        Inherits Form
        Public Sub New()
            InitializeComponent()
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub browseServersButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles browseServersButton.Click
            ' ReSharper restore InconsistentNaming

            opcServerDialog1.Location = machineNameTextBox.Text
            If opcServerDialog1.ShowDialog(Me) = DialogResult.OK Then
                serverClassTextBox.Text = opcServerDialog1.ServerElement.ServerClass
            End If
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub browseItemsButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles browseItemsButton.Click
            ' ReSharper restore InconsistentNaming

            opcDAItemDialog1.ServerDescriptor.MachineName = machineNameTextBox.Text
            opcDAItemDialog1.ServerDescriptor.ServerClass = serverClassTextBox.Text
            If opcDAItemDialog1.ShowDialog() = DialogResult.OK Then
                itemIdTextBox.Text = opcDAItemDialog1.NodeElement.ItemId
            End If
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub readItemButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles readItemButton.Click
            ' ReSharper restore InconsistentNaming

            Dim vtq As DAVtq = Nothing
            Dim exception As Exception = Nothing
            Try
                vtq = easyDAClient1.ReadItem(machineNameTextBox.Text, serverClassTextBox.Text, itemIdTextBox.Text)
            Catch ex As OpcException
                exception = ex
            End Try
            DisplayVtq(vtq)
            DisplayException(exception)
        End Sub

        Private Sub DisplayVtq(ByVal vtq As DAVtq)
            If vtq Is Nothing Then
                valueTextBox.Text = ""
                timestampTextBox.Text = ""
                qualityTextBox.Text = ""
            Else
                valueTextBox.Text = vtq.DisplayValue()
                timestampTextBox.Text = vtq.Timestamp.ToString()
                qualityTextBox.Text = vtq.Quality.ToString()
            End If
        End Sub

        Private Sub DisplayException(ByVal exception As Exception)
            If CObj(exception) Is CObj(Nothing) Then
                exceptionTextBox.Text = ""
            Else
                exceptionTextBox.Text = exception.GetBaseException().Message
            End If
        End Sub

        Private _isItemSubscribedValue As Boolean ' = false
        Private _itemHandle As Integer ' = 0

        Public Property IsItemSubscribed() As Boolean
            Get
                Return _isItemSubscribedValue
            End Get
            Set(ByVal value As Boolean)
                _isItemSubscribedValue = value
                subscribeItemButton.Enabled = Not _isItemSubscribedValue
                changeItemSubscriptionButton.Enabled = _isItemSubscribedValue
                unsubscribeItemButton.Enabled = _isItemSubscribedValue
            End Set
        End Property

        ' ReSharper disable InconsistentNaming
        Private Sub subscribeItemButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles subscribeItemButton.Click
            ' ReSharper restore InconsistentNaming

            Const dataType As Short = VarTypes.Empty
            Dim requestedUpdateRate As Integer = CInt(Fix(requestedUpdateRateNumericUpDown.Value))
            Dim percentDeadband As Single = CSng(percentDeadbandNumericUpDown.Value)
            _itemHandle = easyDAClient1.SubscribeItem(machineNameTextBox.Text, serverClassTextBox.Text, itemIdTextBox.Text, dataType, requestedUpdateRate, percentDeadband)
            IsItemSubscribed = True
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub changeItemSubscriptionButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles changeItemSubscriptionButton.Click
            ' ReSharper restore InconsistentNaming

            Dim groupParameters = New DAGroupParameters(CInt(Fix(requestedUpdateRateNumericUpDown.Value)), CSng(percentDeadbandNumericUpDown.Value))
            easyDAClient1.ChangeItemSubscription(_itemHandle, groupParameters)
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub unsubscribeItemButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles unsubscribeItemButton.Click
            ' ReSharper restore InconsistentNaming

            easyDAClient1.UnsubscribeItem(_itemHandle)
            _itemHandle = 0
            IsItemSubscribed = False
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub easyDAClient1_ItemChanged(ByVal sender As Object, ByVal e As EasyDAItemChangedEventArgs) Handles easyDAClient1.ItemChanged
            ' ReSharper restore InconsistentNaming

            DisplayVtq(e.Vtq)
            DisplayException(e.Exception)
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub browseMachinesButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles browseMachinesButton.Click
            ' ReSharper restore InconsistentNaming

            If computerBrowserDialog1.ShowDialog() = DialogResult.OK Then
                machineNameTextBox.Text = computerBrowserDialog1.SelectedName
            End If
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub aboutButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles aboutButton.Click
            ' ReSharper restore InconsistentNaming

            MessageBox.Show(Me, Reflection.Assembly.GetExecutingAssembly().FullName, "Assembly Name", MessageBoxButtons.OK, MessageBoxIcon.Information)
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub browsePropertiesButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles browsePropertiesButton.Click
            ' ReSharper restore InconsistentNaming

            opcDAPropertyDialog1.ServerDescriptor.MachineName = machineNameTextBox.Text
            opcDAPropertyDialog1.ServerDescriptor.ServerClass = serverClassTextBox.Text
            opcDAPropertyDialog1.NodeDescriptor = itemIdTextBox.Text
            If opcDAPropertyDialog1.ShowDialog() = DialogResult.OK Then
                propertyIdMaskedTextBox.Text = opcDAPropertyDialog1.PropertyElement.PropertyId.ToString()
            End If
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub getPropertyValueButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles getPropertyValueButton.Click
            ' ReSharper restore InconsistentNaming

            Dim propertyId As Integer = Convert.ToInt32(propertyIdMaskedTextBox.Text, CultureInfo.CurrentCulture)
            Dim value As Object = Nothing
            Dim exception As Exception = Nothing
            Try
                value = easyDAClient1.GetPropertyValue(machineNameTextBox.Text, serverClassTextBox.Text, itemIdTextBox.Text, propertyId)
            Catch ex As OpcException
                exception = ex
            End Try
            propertyValueTextBox.Text = (If(value Is Nothing, "(null)", String.Format(CultureInfo.CurrentCulture, "{0}", value)))
            DisplayException(exception)
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub writeItemValueButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles writeItemValueButton.Click
            ' ReSharper restore InconsistentNaming

            Dim value As Object = valueToWriteTextBox.Text
            Dim exception As Exception = Nothing
            Try
                easyDAClient1.WriteItemValue(machineNameTextBox.Text, serverClassTextBox.Text, itemIdTextBox.Text, value)
            Catch ex As OpcException
                exception = ex
            End Try
            DisplayException(exception)
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub closeButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles closeButton.Click
            ' ReSharper restore InconsistentNaming

            Close()
        End Sub

        ' ReSharper disable InconsistentNaming
        Private Sub MainForm_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
            ' ReSharper restore InconsistentNaming

        End Sub
    End Class
End Namespace

Conceptual

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

Imperative Programming Model for OPC Data (Classic and UA)

.NET Framework Demo Applications for OPC Classic