Serial connection - data received

am using serialconnetion to communicate my device.
am facing issue on , data received function , i cannot read all the data which is received from my device. (device send encrypted data)
sometimes the data’s are broken.
here is my code
Var s As String = SerialConnection1.ReadAll(Encodings.ASCII)

Read it into a buffer and process the buffer, you can’t guarantee that all data will be available all at once.

Thanks for response
I try this one

While MySerial.BytesAvailable > 0
Var s As String = MySerial.ReadAll
DataBuffer = DataBuffer + s // DataBuffer is a property

But still , not read all the value.

If I put breakpoint in data received , then it read all the data

Where did you put this code, inside the DataReceived event?