Communicating
Now that the code to establish the connection has been included, the next step
is to actually send and receive data to and from the server. To do this, the
Text2 control should have the following code added to it's KeyPress event:
Sub Text2_KeyPress (KeyAscii As Integer)
If KeyAscii = 13 Then
Socket1.SendLen = Len(Text2.Text)
Socket1.SendData = Text2.Text
KeyAscii = 0: Text2.Text = ""
End If
End Sub
If the user presses the Enter key in the Text2 control, then that text is sent
down to the echo server. The properties used to send data are as follows:
| Property |
Description |
| SendLen |
This property specifies the length of the data being sent to the server.
It should always be set before the data is written to the socket.
After the data has been sent, the value of the property is adjusted to indicate
the actual number of bytes that have been written. |
| SendData |
Setting this property causes the data assigned to it to be written to
the socket. The number of bytes actually written may be less than the amount
specified in the SendLen property if the socket buffers become full. |
Once the data has been sent to the server, it immediately sends the data back
to the client. This generates a Read event in SocketWrench, which should have
the following code:
Sub Socket1_Read (DataLength As Integer, IsUrgent As Integer)
Socket1.RecvLen = DataLength
Text3.Text = Socket1.RecvData
End Sub
The properties used to receive the data are as follows:
| Property |
Description |
| RecvLen |
This property specifies the maximum number of bytes that should be read
from the socket. After the data has been received, the value is changed
to reflect the number of bytes actually read. |
| RecvData |
Reading this property causes data to be read from the socket, up to the
maximum number of bytes specified by the RecvLen property. If the socket
is non-blocking and there is no data to be read, an error is generated. |
The Read event is passed two parameters, the number of bytes that are available
to be read, and a flag that specifies if the data is urgent (also known as "out-of-band"
data, the use of urgent data is an advanced topic outside of the scope of this
document). For more information about the Read event, please refer to the
SocketWrench/VB Technical Reference.