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:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-vbnet">Software</a> / Visual Basic .NET - Line Bricklet

.. |device_identifier_constant| replace:: There is also a :ref:`constant <line_bricklet_vbnet_constants>` for the device identifier of this Bricklet.

.. _line_bricklet_vbnet:

Visual Basic .NET - Line Bricklet
=================================

This is the description of the :ref:`Visual Basic .NET API bindings <api_bindings_vbnet>` for the :ref:`Line Bricklet <line_bricklet>`. General information and technical
specifications for the Line Bricklet are summarized in its :ref:`hardware description
<line_bricklet_description>`.

An :ref:`installation guide <api_bindings_vbnet_install>` for the Visual Basic .NET API
bindings is part of their general description.

.. _line_bricklet_vbnet_examples:


Examples
--------

The example code below is `Public Domain (CC0 1.0)
<http://creativecommons.org/publicdomain/zero/1.0/>`__.

Simple
^^^^^^

`Download (ExampleSimple.vb) <https://github.com/Tinkerforge/line-bricklet/raw/master/software/examples/vbnet/ExampleSimple.vb>`__

.. literalinclude:: Line_Bricklet_VBNET_ExampleSimple.vb
 :language: vbnet
 :linenos:
 :tab-width: 4

Callback
^^^^^^^^

`Download (ExampleCallback.vb) <https://github.com/Tinkerforge/line-bricklet/raw/master/software/examples/vbnet/ExampleCallback.vb>`__

.. literalinclude:: Line_Bricklet_VBNET_ExampleCallback.vb
 :language: vbnet
 :linenos:
 :tab-width: 4

Threshold
^^^^^^^^^

`Download (ExampleThreshold.vb) <https://github.com/Tinkerforge/line-bricklet/raw/master/software/examples/vbnet/ExampleThreshold.vb>`__

.. literalinclude:: Line_Bricklet_VBNET_ExampleThreshold.vb
 :language: vbnet
 :linenos:
 :tab-width: 4

.. _line_bricklet_vbnet_api:

API
---

Since Visual Basic .NET does not support multiple return values directly, we
use the ``ByRef`` keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.




Basic Functions
^^^^^^^^^^^^^^^


.. vbnet:function:: Class BrickletLine(ByVal uid As String, ByVal ipcon As IPConnection)

 Creates an object with the unique device ID ``uid``:

 .. code-block:: vbnet

    Dim line As New BrickletLine("YOUR_DEVICE_UID", ipcon)

 This object can then be used after the IP Connection is connected
 (see examples :ref:`above <line_bricklet_vbnet_examples>`).


.. vbnet:function:: Function BrickletLine.GetReflectivity() As Integer

 Returns the currently measured reflectivity. The reflectivity is
 a value between 0 (not reflective) and 4095 (very reflective).
 
 Usually black has a low reflectivity while white has a high
 reflectivity.
 
 If you want to get the reflectivity periodically, it is recommended 
 to use the callback :vbnet:func:`Reflectivity <BrickletLine.Reflectivity>` and set the period with 
 :vbnet:func:`SetReflectivityCallbackPeriod() <BrickletLine.SetReflectivityCallbackPeriod>`.
 


Advanced Functions
^^^^^^^^^^^^^^^^^^

.. vbnet:function:: Function BrickletLine.GetAPIVersion() As Byte[]

 Returns the version of the API definition (major, minor, revision) implemented
 by this API bindings. This is neither the release version of this API bindings
 nor does it tell you anything about the represented Brick or Bricklet.
 
.. vbnet:function:: Function BrickletLine.GetResponseExpected(ByVal functionId As Byte) As Boolean

 Returns the response expected flag for the function specified by the function
 ID parameter. It is *true* if the function is expected to send a response,
 *false* otherwise.
 
 For getter functions this is enabled by default and cannot be disabled,
 because those functions will always send a response. For callback configuration
 functions it is enabled by default too, but can be disabled by
 :vbnet:func:`SetResponseExpected() <BrickletLine.SetResponseExpected>`. For setter functions it is disabled by default
 and can be enabled.
 
 Enabling the response expected flag for a setter function allows to detect
 timeouts and other error conditions calls of this setter as well. The
 device will then send a response for this purpose. If this flag is disabled for
 a setter function then no response is send and errors are silently ignored,
 because they cannot be detected.
 
 See :vbnet:func:`SetResponseExpected() <BrickletLine.SetResponseExpected>`
 for the list of function ID constants available for this function.
 
.. vbnet:function:: Sub BrickletLine.SetResponseExpected(ByVal functionId As Byte, ByVal responseExpected As Boolean)

 Changes the response expected flag of the function specified by the
 function ID parameter. This flag can only be changed for setter (default value:
 *false*) and callback configuration functions (default value: *true*). For
 getter functions it is always enabled and callbacks it is always disabled.
 
 Enabling the response expected flag for a setter function allows to detect
 timeouts and other error conditions calls of this setter as well. The
 device will then send a response for this purpose. If this flag is disabled for
 a setter function then no response is send and errors are silently ignored,
 because they cannot be detected.
 
 The following function ID constants are available for this function:
 
 * BrickletLine.FUNCTION_SET_REFLECTIVITY_CALLBACK_PERIOD = 2
 * BrickletLine.FUNCTION_SET_REFLECTIVITY_CALLBACK_THRESHOLD = 4
 * BrickletLine.FUNCTION_SET_DEBOUNCE_PERIOD = 6
 
.. vbnet:function:: Sub BrickletLine.SetResponseExpectedAll(ByVal responseExpected As Boolean)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. vbnet:function:: Sub BrickletLine.GetIdentity(ByRef uid As String, ByRef connectedUid As String, ByRef position As Char, ByRef hardwareVersion[] As Byte, ByRef firmwareVersion[] As Byte, ByRef deviceIdentifier As Integer)

 Returns the UID, the UID where the Bricklet is connected to, 
 the position, the hardware and firmware version as well as the
 device identifier.
 
 The position can be 'a', 'b', 'c' or 'd'.
 
 The device identifier numbers can be found :ref:`here <device_identifier>`.
 |device_identifier_constant|
 


Callback Configuration Functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^



.. vbnet:function:: Sub BrickletLine.SetReflectivityCallbackPeriod(ByVal period As Long)

 Sets the period in ms with which the :vbnet:func:`Reflectivity <BrickletLine.Reflectivity>` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :vbnet:func:`Reflectivity <BrickletLine.Reflectivity>` is only triggered if the reflectivity has changed since the
 last triggering.
 
 The default value is 0.
 
.. vbnet:function:: Function BrickletLine.GetReflectivityCallbackPeriod() As Long

 Returns the period as set by :vbnet:func:`SetReflectivityCallbackPeriod() <BrickletLine.SetReflectivityCallbackPeriod>`.
 
.. vbnet:function:: Sub BrickletLine.SetReflectivityCallbackThreshold(ByVal option As Char, ByVal min As Integer, ByVal max As Integer)

 Sets the thresholds for the :vbnet:func:`ReflectivityReached <BrickletLine.ReflectivityReached>` callback. 
 
 The following options are possible:
 
 .. csv-table::
  :header: "Option", "Description"
  :widths: 10, 100
 
  "'x'",    "Callback is turned off"
  "'o'",    "Callback is triggered when the reflectivity is *outside* the min and max values"
  "'i'",    "Callback is triggered when the reflectivity is *inside* the min and max values"
  "'<'",    "Callback is triggered when the reflectivity is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the reflectivity is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0).
 
 The following constants are available for this function:
 
 * BrickletLine.THRESHOLD_OPTION_OFF = "x"C
 * BrickletLine.THRESHOLD_OPTION_OUTSIDE = "o"C
 * BrickletLine.THRESHOLD_OPTION_INSIDE = "i"C
 * BrickletLine.THRESHOLD_OPTION_SMALLER = "<"C
 * BrickletLine.THRESHOLD_OPTION_GREATER = ">"C
 
.. vbnet:function:: Sub BrickletLine.GetReflectivityCallbackThreshold(ByRef option As Char, ByRef min As Integer, ByRef max As Integer)

 Returns the threshold as set by :vbnet:func:`SetReflectivityCallbackThreshold() <BrickletLine.SetReflectivityCallbackThreshold>`.
 
 The following constants are available for this function:
 
 * BrickletLine.THRESHOLD_OPTION_OFF = "x"C
 * BrickletLine.THRESHOLD_OPTION_OUTSIDE = "o"C
 * BrickletLine.THRESHOLD_OPTION_INSIDE = "i"C
 * BrickletLine.THRESHOLD_OPTION_SMALLER = "<"C
 * BrickletLine.THRESHOLD_OPTION_GREATER = ">"C
 
.. vbnet:function:: Sub BrickletLine.SetDebouncePeriod(ByVal debounce As Long)

 Sets the period in ms with which the threshold callback
 
 * :vbnet:func:`ReflectivityReached <BrickletLine.ReflectivityReached>`
 
 is triggered, if the threshold
 
 * :vbnet:func:`SetReflectivityCallbackThreshold() <BrickletLine.SetReflectivityCallbackThreshold>`
 
 keeps being reached.
 
 The default value is 100.
 
.. vbnet:function:: Function BrickletLine.GetDebouncePeriod() As Long

 Returns the debounce period as set by :vbnet:func:`SetDebouncePeriod() <BrickletLine.SetDebouncePeriod>`.
 


.. _line_bricklet_vbnet_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive time critical or recurring data from
the device. The registration is done by assigning a procedure to an callback
property of the device object:

 .. code-block:: vbnet

    Sub Callback(ByVal sender As BrickletLine, ByVal value As Short)
        Console.WriteLine("Value: {0}", value)
    End Sub

    AddHandler line.Example, AddressOf Callback

The available callback property and their type of parameters are described below.

.. note::
 Using callbacks for recurring events is *always* preferred
 compared to using getters. It will use less USB bandwidth and the latency
 will be a lot better, since there is no round trip time.


.. vbnet:function:: Event BrickletLine.Reflectivity(ByVal sender As BrickletLine, ByVal reflectivity As Integer)


 This callback is triggered periodically with the period that is set by
 :vbnet:func:`SetReflectivityCallbackPeriod() <BrickletLine.SetReflectivityCallbackPeriod>`. The parameter is the reflectivity
 of the sensor.
 
 :vbnet:func:`Reflectivity <BrickletLine.Reflectivity>` is only triggered if the reflectivity has changed since the
 last triggering.
 

.. vbnet:function:: Event BrickletLine.ReflectivityReached(ByVal sender As BrickletLine, ByVal reflectivity As Integer)


 This callback is triggered when the threshold as set by
 :vbnet:func:`SetReflectivityCallbackThreshold() <BrickletLine.SetReflectivityCallbackThreshold>` is reached.
 The parameter is the reflectivity of the sensor.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :vbnet:func:`SetDebouncePeriod() <BrickletLine.SetDebouncePeriod>`.
 


.. _line_bricklet_vbnet_constants:

Constants
^^^^^^^^^

.. vbnet:attribute:: Const BrickletLine.DEVICE_IDENTIFIER

 This constant is used to identify a Line Bricklet.

 The :vbnet:func:`GetIdentity() <BrickletLine.GetIdentity>` function and the
 :vbnet:func:`EnumerateCallback <IPConnection.EnumerateCallback>`
 callback of the IP Connection have a ``deviceIdentifier`` parameter to specify
 the Brick's or Bricklet's type.

