GuruxFile component

This guide shows you how to use Gurux file component (GXFile) in the Visual Basic environment. The development version of GXFile comes with a Visual Basic example. Source code is available at sourceforge.net

Adding GXFile component to the project

Start Visual Basic
Open the project where you want to add the GXFile component, or create the new one
Select Components from the Project menu
Select the GXFile component and click OK to finish

Using components with Visual Basic

You can either drag the component to the form, or create it dynamically.

Creating component dynamically

To create component in runtime, select References in the Project menu. The dialog shows available components, select the one(s) to use (in this case Gurux file component). Click OK to finish. The following example shows how to create a GXFile component.

Dim WithEvents GXFile1 As GXFile
'Create new component
Set GXFile1= New GXFile

Note: WithEvents means that component can receive asynchronous calls.

Setting Media Properties

You can either select appropriate settings in the Properties dialog or edit the settings programmatically.

'Set file path to watch.
GXFile1.FilePath = "C:\temp\"
GXFile1.Filter = "*.txt"
GXFile1.RemoveAfterRead = True
GXFile1.Open

Sending and receiving packets

All data is sent asynchronously. Response is received as a Received event message.

Receiving event messages

Because the GXFile1 variable was introduced as the WithEvents type, an incoming event message from the system can be received very easily. The following example shows how to create a handler for the Received method.

Select GXFile1 in the left menu above the code window. In the right menu, select the event message, on which you want to make the handler (OnReceived). Code window then displays following:

Private Sub GXFile1_OnReceived(ByVal Data As String, ByVal SenderInfo As String)
   'Add code here
End Sub

Now create handler for OnError event.

Error Handling

It's very important to consider error handling when sending and receiving data. The connection can drop down, or something else unexpected may happen. If something unwanted happens, Gurux file component returns error.The following example shows how to handle errors in Visual Basic.

  Sub SendData(Data As Variant)
    On Error GoTo GXErrHandler
    'Send Data
    GXFile1.Write "c:\temp\test.txt", "Hello world."
    Exit Sub
    GXErrHandler:
    'Show occurred error
    MsgBox Err.Description
  End Sub

Using the components from development environment

Using from .NET | Using from Visual Basic | Using from C++