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http://codecenter.softwaretoolbox.com
Be sure to check out the OPC Browser Tutorial. This page shows you how to: Browsing Available OPC Servers The following code assumes that an empty form exists with a single listbox control in it. Place the following code in the Form_load event: Browsing Available Tags The following code assumes that an empty for exists with a single listbox control in it. Place the following code in the Form_load event:
OPC Browsing
'define a browser object
Dim o As New
OPCUserObjects.OPCUserBrowseMachine
'run the dialog
o.RunMe()
'show the result
MessageBox.Show(o.MachineName) 'define our browser object
Dim o As New
OPCUserObjects.OPCUserBrowseMachine
'specify the machine we will browse
'no value means local computer
o
.MachineName = ""
'run the dialog
o.RunMe()
'now to check the result
'if the serverclass is blank and the machine is blank
'then nothing was selected
If ( _
o.ServerClass
.Equals(Text.Empty) _
And _
o.MachineName.Equals(Text.Empty) _
) Then
'nothing selected
MessageBox.Show("Dialog cancelled")
Else
'user picked...
MessageBox.Show(o.ServerClass)
End If
The following code assumes that an empty for exists with a single listbox control in it. Place the following code in the Form_load event:
'
'display a message in the listbox to acknowledge that something is happening...
ListBox1.Items.Add("please wait...")
ListBox1.Update()
'
'now to do the opc server browsing
Try
'
'define ourselves an opc web client
Dim objOWC As New OPCLabs.EasyOPCDANet.EasyDACOM
'
'this is the name of the computer we want to look at
Dim strMachineName As String = ""
'
'now capture the browsed servers into a dictionary object
Dim ServerElements As IDictionary =
objOWC.BrowseServers(strMachineName)
'
'now clear any messages/items in the listbox
ListBox1.Items.Clear()
If Not ServerElements Is Nothing Then
'
'now iterate thru each element within the dictionary
For Each key As Object In ServerElements.Keys
'
'now get the server element from the collection into a variable
Dim server As
OPCLabs.EasyOPCDANet.IServerElementNet = ServerElements.Item(key)
'
'add the progid of the opc server into the listbox
ListBox1.Items.Add(server.ProgID)
Next
End If
Catch ex As Exception
'
'display any exceptions in a messagebox
MessageBox.Show("Error: " & ex.Message)
End Try
Browsing Available OPC Groups/Branches
Try
'lets create an instance of our OPC Web Client
'we will use the COM interface (not the webservice)
Dim EasyDA As New OPCLabs.EasyOPCDANet.EasyDACOM
'
'now lets define a dictionary collection
Dim BranchElements As System.Collections.IDictionary
'
'the name of the computer we want to browse on
Dim strMachineName As String ""
'
'capture the results of the browseBranches function into the dictionary
BranchElements = EasyDA
.BrowseBranches(strMachineName, "OPCLabs.KitServer.2", "")
'
'make sure our dictionary is not empty/null
If Not BranchElements Is Nothing Then
'
'lets now iterate thru the elements within the dictionary
For Each Key As Object In BranchElements.Keys
'
'define a branch object and set it to the object in the dictionary object
'at the position specified by the "key" variable, which happens
'to be the "name" of the branch.
Dim BranchElement As OPCLabs.EasyOPCDANet.INodeElementNet = BranchElements.Item(Key)
'
'if this is a branch, then add it to our listbox
If BranchElement.IsBranch Then
ListBox1.Items.Add(BranchElement.ItemID)
End If
Next
End If
Catch ex As Exception
'
'show any exception in a message box
MessageBox.Show("Error: " & ex.Message)
End Try
'create a tag browser object
Dim objOWC As New
OPCUserObjects.OPCUserBrowseItem
'set the server we want to browse
'along with the machine it is on
objOWC.MachineName = ""
objOWC.ServerClass = "OPCLabs.KitServer.2"
'run the dialog
objOWC.RunMe()
'now to see what was selected
If (objOWC.ItemID.Equals(Text.Empty)) Then
'nothing was selected, or the dialog was cancelled
MessageBox.Show("Nothing selected")
Else
'the user picked something...
MessageBox.Show(objOWC
.ItemID)
End If
ListBox1.Items.Clear()
ListBox1.Items.Add("Please wait...")
Try
'
'create ourselves an opc web client object
Dim objOWC As New OPCLabs.EasyOPCDANet.EasyDACOM
'
'the computer we want to browse on
Dim strMachineName As String = ""
'
'create a dictionary object to receive the leaves in
Dim LeafElements As IDictionary = objOWC.BrowseLeafs(strMachineName, "
OPCLabs.KitServer.2", "Simulation")
'
'clear any messages/items in the listbox
ListBox1.Items.Clear()
'
'iterate thru each item in the dictionary
For Each Key As Object In LeafElements.Keys
'
'get the dictionary element into an object we can use to query
Dim LeafElement As
OPCLabs.EasyOPCDANet.INodeElementNet = LeafElements.Item(Key)
'
'now add some information regarding the object to the listbox
With LeafElement
ListBox1.Items.Add("Tag: " & .Name & ", ItemID: " & .ItemID)
End With
Next
Catch ex As Exception
'display any exceptions to the screen
MessageBox.Show("Error: " & ex.Message)
End Try
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