VERSION 5.00
Object = "{6B7E6392-850A-101B-AFC0-4210102A8DA7}#1.3#0"; "COMCTL32.OCX"
Begin VB.Form frmAddItem 
   Caption         =   "Add Item"
   ClientHeight    =   4680
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   8520
   ControlBox      =   0   'False
   LinkTopic       =   "Form1"
   ScaleHeight     =   4680
   ScaleWidth      =   8520
   ShowInTaskbar   =   0   'False
   StartUpPosition =   1  'CenterOwner
   Begin VB.Frame Browsing 
      Caption         =   "Browsing"
      Height          =   2895
      Left            =   0
      TabIndex        =   10
      Top             =   1680
      Width           =   8415
      Begin VB.ComboBox AccessFilter 
         Height          =   315
         ItemData        =   "frmAddItem.frx":0000
         Left            =   6720
         List            =   "frmAddItem.frx":0010
         TabIndex        =   18
         Text            =   "Any"
         ToolTipText     =   "Select an access type to filter the list of items displayed"
         Top             =   360
         Width           =   1215
      End
      Begin ComctlLib.ListView lvItemView 
         Height          =   2055
         Left            =   3960
         TabIndex        =   14
         ToolTipText     =   "Select an item from this list by double clicking on the item"
         Top             =   720
         Width           =   4335
         _ExtentX        =   7646
         _ExtentY        =   3625
         View            =   3
         Sorted          =   -1  'True
         LabelWrap       =   -1  'True
         HideSelection   =   -1  'True
         HideColumnHeaders=   -1  'True
         _Version        =   327682
         ForeColor       =   -2147483640
         BackColor       =   -2147483643
         BorderStyle     =   1
         Appearance      =   1
         NumItems        =   0
      End
      Begin VB.ComboBox DataTypeFilter 
         Height          =   315
         ItemData        =   "frmAddItem.frx":003C
         Left            =   5400
         List            =   "frmAddItem.frx":006F
         TabIndex        =   13
         Text            =   "Native"
         ToolTipText     =   "Select a datatype to filter the list of items displayed"
         Top             =   360
         Width           =   1215
      End
      Begin VB.TextBox ItemNameFilter 
         Height          =   285
         Left            =   3960
         TabIndex        =   12
         Text            =   "*"
         ToolTipText     =   "Enter a filter expression to reduce the number of item displayed Ex. Temp* , N* ,  *"
         Top             =   360
         Width           =   1335
      End
      Begin ComctlLib.TreeView tvBranchView 
         Height          =   2535
         Left            =   120
         TabIndex        =   11
         ToolTipText     =   "Expand the branches of the browser tree to access individual item names"
         Top             =   240
         Width           =   3735
         _ExtentX        =   6588
         _ExtentY        =   4471
         _Version        =   327682
         HideSelection   =   0   'False
         LabelEdit       =   1
         LineStyle       =   1
         Style           =   7
         Appearance      =   1
      End
      Begin VB.Label Label5 
         Caption         =   "Access Filter"
         Height          =   255
         Left            =   6720
         TabIndex        =   17
         Top             =   120
         Width           =   1095
      End
      Begin VB.Label Label4 
         Caption         =   "Datatype Filter"
         Height          =   255
         Left            =   5400
         TabIndex        =   16
         Top             =   120
         Width           =   1095
      End
      Begin VB.Label Label1 
         Caption         =   "Leaf Filter"
         Height          =   255
         Left            =   3960
         TabIndex        =   15
         Top             =   120
         Width           =   855
      End
   End
   Begin VB.CommandButton Abort 
      Caption         =   "Done"
      Height          =   375
      Left            =   6960
      TabIndex        =   5
      ToolTipText     =   "Click here when you have finished adding tags"
      Top             =   720
      Width           =   1455
   End
   Begin VB.CommandButton AddItem 
      Caption         =   "Add Item"
      Height          =   375
      Left            =   6960
      TabIndex        =   4
      ToolTipText     =   "Click here to add a tag to the current group"
      Top             =   240
      Width           =   1455
   End
   Begin VB.CommandButton Validate 
      Caption         =   "Validate"
      Height          =   375
      Left            =   2640
      TabIndex        =   3
      ToolTipText     =   "Once you have entered an ItemID and Datatype click here to test the entry"
      Top             =   720
      Width           =   1575
   End
   Begin VB.CheckBox ActiveState 
      Alignment       =   1  'Right Justify
      Caption         =   "Active State:"
      Height          =   375
      Left            =   360
      TabIndex        =   2
      ToolTipText     =   "Set the initial Active state of the item to be added"
      Top             =   1080
      Value           =   1  'Checked
      Width           =   1215
   End
   Begin VB.ComboBox DataType 
      Height          =   315
      ItemData        =   "frmAddItem.frx":00D4
      Left            =   960
      List            =   "frmAddItem.frx":0107
      TabIndex        =   1
      Text            =   "Native"
      ToolTipText     =   "Select the datatype that will be applied to this item"
      Top             =   720
      Width           =   1575
   End
   Begin VB.TextBox ItemID 
      Height          =   285
      Left            =   960
      TabIndex        =   0
      Text            =   "Channel_1.Device_1.R0"
      ToolTipText     =   "Enter a valid Item ID String for the server you are using, this default item is for KEPServerEX"
      Top             =   360
      Width           =   5775
   End
   Begin VB.Frame Frame1 
      Caption         =   "Item Definition"
      Height          =   1455
      Left            =   0
      TabIndex        =   6
      Top             =   120
      Width           =   6855
      Begin VB.TextBox Report 
         Height          =   285
         Left            =   2640
         Locked          =   -1  'True
         TabIndex        =   9
         ToolTipText     =   "This box will report the results of the Validate Item button"
         Top             =   1080
         Width           =   4095
      End
      Begin VB.Label Label2 
         Caption         =   "Item ID:"
         Height          =   255
         Left            =   360
         TabIndex        =   8
         Top             =   240
         Width           =   615
      End
      Begin VB.Label Label3 
         Caption         =   "Data Type:"
         Height          =   255
         Left            =   120
         TabIndex        =   7
         Top             =   600
         Width           =   855
      End
   End
End
Attribute VB_Name = "frmAddItem"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
' The Add OPC Item form allows the user to set the ItemID,
' DataType, and Active state for an OPC item that will added
' to the selected group. When this form is displayed the
' tvTreeView on the main form is disable to prevent the
' user from invoking an Add group or Add Server menu.
' This form will only be invoke while the user has an
' existing OPC server group selected.  This means that
' global variable SelectedOPCGroup and SelectedOPCServer
' will be set.
'
' The Add item form is preconfigured with a simple default
' ItemID string that will work in our KEPServerEX
' OPC Servers when running the Simdemo
' project in server.  If you are using a driver
' other than our Simulator or using a differnt OPC server
' altogether simply replace this default ItemID with a
' fully qualified item id for the driver or server being used.
' You can also browse the tag space of the server you are connected
' with to receive a list of item IDs.
'
' You'll also notice that I preselect a DataType of "Native" for
' the item.  Normally when you add an item to an OPC server
' group you will set the datatype to format that you desire for
' the item.  OPC and COM objects in general support many data
' type formats.  In some cases you may not know the format of the
' data for ItemID you are trying to register.  In these cases you can
' specify what is refered to as either Empty or Native.  When
' selecting a datatype of Native you are telling the OPC server
' to pick the default data type of the item for you.
'
' There is one possible problem with using the Native datatype
' and allowing the server to pick the data type.  Sometimes the
' default data type for an item is an Unsigned format.  At this
' time the Automation Wrapper can have problems with some
' Unsigned datatypes.  I have seen a problem with arrays of
' Unsigned values.  I have however successfully used Unsigned
' values of single items.  In general try to select a data type
' from those presented in the drop down Datatype control.
' For more reference on the datatype available for OPC items
' use the VB help system and search for "VarType Constants"
' You'll also notice that I have provided some array type
' selections. An array data type is built by adding the VB
' Const vbArray + (desired type), you'll see this in the
' DataType combobox's ItemData and on the VB help page.
'
' The Active state allows you to set whether or not the OPC
' item you intend to add will be actively acquiring data or
' idle.  The active state of an OPC item is an important tool
' in controlling how an OPC server is talking to you phsyical
' device.  The amount of data that an OPC server is gathering
' from a device depends on two factors, the number of actual
' OPC items added to the OPC server/groups and the number of
' those item that are marked as active.  This is an important
' consideration.  When designing your OPC client application
' you can control the operation of the OPC server by adding
' OPC items and deleting them as need.  This works but it
' forces the OPC server to do a great deal of memory allocation
' and releasing as well as potentially interupting the order
' of how data is being polled from the server.  A better way
' to control how much data is being acquired by the OPC server
' is to use the active state of the item.  By using the active
' state of the item you can essential turn an item off. When
' this occurs the OPC server will stop scanning that item from
' the physical device.  This of course will reduce the
' bandwidth requirements of the OPC server.  By using the
' active state of the item instead of adding and deleting the
' items you allow the OPC server to operate at peak performance.
'
' The AddItem form also demonstrates another important and
' useful component of the OPC inteface, that is the Validate
' method found on the OPCItems object of the Automation
' Wrapper.  The Validate method allows you to ask the OPC
' server if the ItemID, DataType, and Active State of the item
' you intend to add is valid.  Essentially the Validate
' method is just like calling the acutal AddItem mehtod but
' it doesn't actually add the item to the server.  The OPC
' server will return error status of the item.  This is a great
' way to let the users of your OPC client application known
' that the item they are entering is valid
'
' Just like the Add OPC Group form, the actual addition of the
' OPC item occurs over in frmMain since this is where the item
' will be added to the lvListView control.  The actual
' AddOPCItem function of the OPCGroupClass is shown in frmMain.
' Calling the ValidateOPCItem of the OPCGroupClass is shown
' here directly.
'
' This form also handles most of tag browsing code for this
' example application.  The browse interface is housed in the
' OPCBrowserClass.  Most of the actual work is done here since
' majority of the work is in managing the treeviiew and listview
' controls.
'
' I take a simplified approach to maintaining browser sync with the OPC
' server.  The browse interface provides a number of method that allow you to
' move up and down the browse tree of the OPC server.  You can use these
' methods to change what segment of the server's tag space you can access
' at a given level.  In this example I keep track of the various branches
' in the browse space and use this data to do a simple Move operation that
' always starts at the root of the server browse space.  In this way it
' would be pretty hard to get out of sync with the server.



Option Explicit
Option Base 1

' This object is returned from the OPCServerClass function
' GetServerBrowseObject. The OPCBrowserClass object is a relative thin
' wrapper for the Automation browse object.
'
Dim OPCBrowserClassObj As OPCBrowserClass

' The variable is used to generate a number of dummy treeview
' nodes that allow the tree to always have an expansion available.
' In this way we can get the data for each branch of the browse
' space when the user expands a branch. You will see the
' addition of the Dummy node each time a branch is collapsed.
' By the same token the dummy node is removed before the branch is
' completely expanded so the user never sees this phatom node.
'
Dim DummyNodeNum As Integer