Develop Reference

How to restore the hidden wpf window from process

In my wpf window I hides the window and remove it from task bar on close.
How I can activate that window from running process. I have tried many ways but no success.
Here is my sample code to activate hidden window.
private void checkIfProcessRunning()
{
// get the name of our process
string proc = Process.GetCurrentProcess().ProcessName;
// get the list of all processes by that name
Process[] processes = Process.GetProcessesByName(proc);
// if there is more than one process...
if (processes.Length > 1)
{
// Assume there is our process, which we will terminate,
// and the other process, which we want to bring to the
// foreground. This assumes there are only two processes
// in the processes array, and we need to find out which
// one is NOT us.
RzLogger.WriteLine("process are running count:" + processes.Length);
// get our process
Process p = Process.GetCurrentProcess();
int n = 0; // assume the other process is at index 0
// if this process id is OUR process ID...
if (processes[0].Id == p.Id)
{
RzLogger.WriteLine("other process are at 1");
// then the other process is at index 1
n = 1;
}
// get the window handle
IntPtr hWnd = processes[n].MainWindowHandle;
RzLogger.WriteLine("main handle is:" + hWnd);
// if iconic, we need to restore the window
if (IsIconic(hWnd))
{
RzLogger.WriteLine("is minimized");
ShowWindowAsync(hWnd, SW_SHOWNORMAL);
ShowWindowAsync(hWnd, SW_RESTORE);
SetForegroundWindow(hWnd);
}
// bring it to the foreground
SetForegroundWindow(hWnd);
// exit our process
Application.Current.Shutdown();
return;
}
// ... continue with your application initialization here.
}
The problem is I am getting handle as 0 always.
Is there a way to do this? and I don't want to show anything in taskbar

Heres an example how to use pipes.
Using a named mutex in addition to this gets rid of some problems if you start instances very fast (you might end up with more then 1 server in that case - so create a named mutex early on and if present - just send the Show() over the pipe and close.
Created from VS2017 default Wpf-Project. Compile it, start a Debug-Build, go to the output folder and start the exe again to show what it does.
MainWindow.xaml
<Window x:Class="interproc.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:interproc"
mc:Ignorable="d"
Title="MainWindow"
Height="350"
Width="525"
Loaded="Window_Loaded">
<Grid>
<TextBlock Name="tb"
Background="Yellow"
Text="..."
Margin="50" />
</Grid>
</Window>
MainWindow.xaml.cs
using System;
using System.Windows;
using System.IO.Pipes;
using System.Threading;
using System.Windows.Threading;
namespace InterprocessCommunicationViaPipes
{
/// <summary>
/// Commands used to communiate via pipe
/// </summary>
public enum EPipeCommands : byte
{
None, Show, Hide, Close
};
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
Title = DateTime.UtcNow.ToString("o");
}
/// <summary>
/// Name of the pipe used for interprocess communication
/// </summary>
private const string PipeName = "MyCoolApp";
/// <summary>
/// prevents double Close() calls
/// </summary>
private bool isClosing = false;
/// <summary>
/// Server
/// </summary>
private NamedPipeServerStream pipeServerStream = null;
/// <summary>
/// Thread server is running in
/// </summary>
private Thread ServerThread;
void ActOnPipeCommand(EPipeCommands c)
{
Application.Current.Dispatcher.Invoke(DispatcherPriority.Background,
new ThreadStart(
delegate
{
tb.Text += $"\n{DateTime.UtcNow:o} recieved {c}\n";
switch (c)
{
case EPipeCommands.None:
return;
case EPipeCommands.Hide:
Hide();
break;
case EPipeCommands.Show:
if (this.WindowState == WindowState.Minimized)
WindowState = WindowState.Normal;
Visibility = Visibility.Visible;
break;
case EPipeCommands.Close when !isClosing:
Close();
break;
case EPipeCommands.Close:
tb.Text += $"Already closing.\n";
break;
default:
tb.Text += $"Unmapped pipe action: {c.ToString()}\n";
break;
}
}));
}
/// <summary>
/// Server running?
/// </summary>
/// <returns></returns>
bool CheckIsRunning()
{
NamedPipeClientStream clientStream = new NamedPipeClientStream(PipeName);
try
{
clientStream.Connect(1000);
}
catch (TimeoutException)
{
tb.Text = $"No Server found.";
return false;
}
clientStream.WriteByte((byte)EPipeCommands.Show);
return true;
}
EPipeCommands InterpretePipeCommand(int v)
{
if (Enum.TryParse<EPipeCommands>($"{v}", out var cmd))
return cmd;
return EPipeCommands.None;
}
/// <summary> Creates the server, listens to connectiontrys,
/// reads 1 byte & disconnects </summary>
/// <param name="data"></param>
void PipeServer(object data)
{
pipeServerStream = new NamedPipeServerStream(
PipeName, PipeDirection.InOut,
2, PipeTransmissionMode.Byte);
do
{
pipeServerStream.WaitForConnection();
if (pipeServerStream.IsConnected && !isClosing)
{
ActOnPipeCommand(
InterpretePipeCommand(
pipeServerStream.ReadByte()));
}
pipeServerStream.Disconnect();
}
while (!isClosing);
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
if (CheckIsRunning())
Close();
else
{
ServerThread = new Thread(PipeServer);
ServerThread.Start();
tb.Text = "Starting new pipe server.\n";
Closing += (a, b) => isClosing = true;
}
}
}
}

Sending and Receiving data from virtual Com port - C# [duplicate]

I just started learning how to send and receive data from my hardware through the C# GUI.
Can anyone please write a detail how to read data from the serial port?

SerialPort (RS-232 Serial COM Port) in C# .NET
This article explains how to use the SerialPort class in .NET to read and write data, determine what serial ports are available on your machine, and how to send files. It even covers the pin assignments on the port itself.
Example Code:
using System;
using System.IO.Ports;
using System.Windows.Forms;
namespace SerialPortExample
{
class SerialPortProgram
{
// Create the serial port with basic settings
private SerialPort port = new SerialPort("COM1",
9600, Parity.None, 8, StopBits.One);
[STAThread]
static void Main(string[] args)
{
// Instatiate this class
new SerialPortProgram();
}
private SerialPortProgram()
{
Console.WriteLine("Incoming Data:");
// Attach a method to be called when there
// is data waiting in the port's buffer
port.DataReceived += new
SerialDataReceivedEventHandler(port_DataReceived);
// Begin communications
port.Open();
// Enter an application loop to keep this thread alive
Application.Run();
}
private void port_DataReceived(object sender,
SerialDataReceivedEventArgs e)
{
// Show all the incoming data in the port's buffer
Console.WriteLine(port.ReadExisting());
}
}
}

I spent a lot of time to use SerialPort class and has concluded to use SerialPort.BaseStream class instead. You can see source code: SerialPort-source and
SerialPort.BaseStream-source for deep understanding.
I created and use code that shown below.
The core function
public int Recv(byte[] buffer, int maxLen)
has name and works like "well known" socket's recv().
It means that
in one hand it has timeout for no any data and throws TimeoutException.
In other hand, when any data has received,
it receives data either until maxLen bytes
or short timeout (theoretical 6 ms) in UART data flow
.
public class Uart : SerialPort
{
private int _receiveTimeout;
public int ReceiveTimeout { get => _receiveTimeout; set => _receiveTimeout = value; }
static private string ComPortName = "";
/// <summary>
/// It builds PortName using ComPortNum parameter and opens SerialPort.
/// </summary>
/// <param name="ComPortNum"></param>
public Uart(int ComPortNum) : base()
{
base.BaudRate = 115200; // default value
_receiveTimeout = 2000;
ComPortName = "COM" + ComPortNum;
try
{
base.PortName = ComPortName;
base.Open();
}
catch (UnauthorizedAccessException ex)
{
Console.WriteLine("Error: Port {0} is in use", ComPortName);
}
catch (Exception ex)
{
Console.WriteLine("Uart exception: " + ex);
}
} //Uart()
/// <summary>
/// Private property returning positive only Environment.TickCount
/// </summary>
private int _tickCount { get => Environment.TickCount & Int32.MaxValue; }
/// <summary>
/// It uses SerialPort.BaseStream rather SerialPort functionality .
/// It Receives up to maxLen number bytes of data,
/// Or throws TimeoutException if no any data arrived during ReceiveTimeout.
/// It works likes socket-recv routine (explanation in body).
/// Returns:
/// totalReceived - bytes,
/// TimeoutException,
/// -1 in non-ComPortNum Exception
/// </summary>
/// <param name="buffer"></param>
/// <param name="maxLen"></param>
/// <returns></returns>
public int Recv(byte[] buffer, int maxLen)
{
/// The routine works in "pseudo-blocking" mode. It cycles up to first
/// data received using BaseStream.ReadTimeout = TimeOutSpan (2 ms).
/// If no any message received during ReceiveTimeout property,
/// the routine throws TimeoutException
/// In other hand, if any data has received, first no-data cycle
/// causes to exit from routine.
int TimeOutSpan = 2;
// counts delay in TimeOutSpan-s after end of data to break receive
int EndOfDataCnt;
// pseudo-blocking timeout counter
int TimeOutCnt = _tickCount + _receiveTimeout;
//number of currently received data bytes
int justReceived = 0;
//number of total received data bytes
int totalReceived = 0;
BaseStream.ReadTimeout = TimeOutSpan;
//causes (2+1)*TimeOutSpan delay after end of data in UART stream
EndOfDataCnt = 2;
while (_tickCount < TimeOutCnt && EndOfDataCnt > 0)
{
try
{
justReceived = 0;
justReceived = base.BaseStream.Read(buffer, totalReceived, maxLen - totalReceived);
totalReceived += justReceived;
if (totalReceived >= maxLen)
break;
}
catch (TimeoutException)
{
if (totalReceived > 0)
EndOfDataCnt--;
}
catch (Exception ex)
{
totalReceived = -1;
base.Close();
Console.WriteLine("Recv exception: " + ex);
break;
}
} //while
if (totalReceived == 0)
{
throw new TimeoutException();
}
else
{
return totalReceived;
}
} // Recv()
} // Uart

Note that usage of a SerialPort.DataReceived event is optional. You can set proper timeout using SerialPort.ReadTimeout and continuously call SerialPort.Read() after you wrote something to a port until you get a full response.
Moreover, you can use SerialPort.BaseStream property to extract an underlying Stream instance. The benefit of using a Stream is that you can easily utilize various decorators with it:
var port = new SerialPort();
// LoggingStream inherits Stream, implements IDisposable, needed abstract methods and
// overrides needed virtual methods.
Stream portStream = new LoggingStream(port.BaseStream);
portStream.Write(...); // Logs write buffer.
portStream.Read(...); // Logs read buffer.
For more information:
Top 5 SerialPort Tips article by Kim Hamilton, BCL Team Blog
C# await event and timeout in serial port communication discussion on StackOverflow

Naudio record microphone for X amount of seconds

Currently I can record the microphone input using the Naudio .dll with this:
public void recordInput()
{
Console.WriteLine("Now recording...");
waveSource = new WaveIn();
waveSource.WaveFormat = new WaveFormat(16000, 1);
waveSource.DataAvailable += new EventHandler<WaveInEventArgs>(waveSource_DataAvailable);
waveSource.RecordingStopped += new EventHandler<StoppedEventArgs>(waveSource_RecordingStopped);
//string tempFile = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString() + ".wav");
string tempFile = Path.Combine(#"C:\Users\Nick\Desktop", "test.wav");
waveFile = new WaveFileWriter(tempFile, waveSource.WaveFormat);
waveSource.StartRecording();
myTimer.Interval = 5000;
myTimer.Tick += new EventHandler(myTimer_Tick);
myTimer.Start();
}
Currently I used an eventhandler to wait for 5 seconds and then onTick I stop recording. However this is causing problems because I am having trouble waiting for the recording task to finish in the main part of the code where I call:
public string voiceToText()
{
recordInput();
//Somehow wait here until record is done then proceed.
convertToFlac();
return "done";
}
I've tried putting the Naudio in a thread and using a waitOne(); but waveSource.StartRecording(); is put in an eventhandler and thread an expection. I've also tried using a Thread.Sleep(5000) and stop recording after that thread finishes but the audio only records the first 500mS of audio for some reason.
I'm pretty new to c# and don't fully understand threading so any help or seperate approach is welcome.

I know this is an old topic, but here is some code that I made for one of my projects and that records audio for x seconds (it uses NAudio.Lame to convert the wave file to mp3):
public class Recorder
{
/// <summary>
/// Timer used to start/stop recording
/// </summary>
private Timer _timer;
private WaveInEvent _waveSource;
private WaveFileWriter _waveWriter;
private string _filename;
private string _tempFilename;
public event EventHandler RecordingFinished;
/// <summary>
/// Record from the mic
/// </summary>
/// <param name="seconds">Duration in seconds</param>
/// <param name="filename">Output file name</param>
public void RecordAudio(int seconds, string filename)
{
/*if the filename is empty, throw an exception*/
if (string.IsNullOrEmpty(filename))
throw new ArgumentNullException("The file name cannot be empty.");
/*if the recording duration is not > 0, throw an exception*/
if (seconds <= 0)
throw new ArgumentNullException("The recording duration must be a positive integer.");
_filename = filename;
_tempFilename = $"{Path.GetFileNameWithoutExtension(filename)}.wav";
_waveSource = new WaveInEvent
{
WaveFormat = new WaveFormat(44100, 1)
};
_waveSource.DataAvailable += DataAvailable;
_waveSource.RecordingStopped += RecordingStopped;
_waveWriter = new WaveFileWriter(_tempFilename, _waveSource.WaveFormat);
/*Start the timer that will mark the recording end*/
/*We multiply by 1000 because the Timer object works with milliseconds*/
_timer = new Timer(seconds * 1000);
/*if the timer elapses don't reset it, stop it instead*/
_timer.AutoReset = false;
/*Callback that will be executed once the recording duration has elapsed*/
_timer.Elapsed += StopRecording;
/*Start recording the audio*/
_waveSource.StartRecording();
/*Start the timer*/
_timer.Start();
}
/// <summary>
/// Callback that will be executed once the recording duration has elapsed
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void StopRecording(object sender, ElapsedEventArgs e)
{
/*Stop the timer*/
_timer?.Stop();
/*Destroy/Dispose of the timer to free memory*/
_timer?.Dispose();
/*Stop the audio recording*/
_waveSource.StopRecording();
}
/// <summary>
/// Callback executed when the recording is stopped
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void RecordingStopped(object sender, StoppedEventArgs e)
{
_waveSource.DataAvailable -= DataAvailable;
_waveSource.RecordingStopped -= RecordingStopped;
_waveSource?.Dispose();
_waveWriter?.Dispose();
/*Convert the recorded file to MP3*/
ConvertWaveToMp3(_tempFilename, _filename);
/*Send notification that the recording is complete*/
RecordingFinished?.Invoke(this, null);
}
/// <summary>
/// Callback executed when new data is available
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void DataAvailable(object sender, WaveInEventArgs e)
{
if (_waveWriter != null)
{
_waveWriter.Write(e.Buffer, 0, e.BytesRecorded);
_waveWriter.Flush();
}
}
/// <summary>
/// Converts the recorded WAV file to MP3
/// </summary>
private void ConvertWaveToMp3(string source, string destination)
{
using (var waveStream = new WaveFileReader(source))
using(var fileWriter = new LameMP3FileWriter(destination, waveStream.WaveFormat, 128))
{
waveStream.CopyTo(fileWriter);
waveStream.Flush();
}
/*Delete the temporary WAV file*/
File.Delete(source);
}
}
And here is how to use it in your code:
var rec = new Recorder();
/*This line allows us to be notified when the recording is complete and the callback 'OnRecordingFinished' will be executed*/
rec.RecordingFinished += OnRecordingFinished;
rec.RecordAudio(seconds, recPath);
private void OnRecordingFinished(object sender, RecordingContentArgs e)
{
//Put your code here to process the audio file
}

If you aren't running in a Windows Forms or WPF application, then you should use WaveInEvent instead, so that a background thread is set up to handle the callbacks. The default constructor for WaveIn uses Windows messages.

NullReferenceException when Firing an Event [duplicate]

This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 8 years ago.
The problem is: I get a NullReferenceException but I can't seem to find out why. (I just start with C#) and have read the C# for kids from Microsoft. It explained a lot but this I do not understand.
But I don't get the piece of code which throw the exception to my head.
Code is:
using System;
using System.Collections.Generic;
using System.Linq; using System.Text;
using System.IO.Ports;
using PlugwiseLib.BLL.BC;
using plugwiseLib.BLL.BPC;
using System.Text.RegularExpressions;
using System.Threading;
using System.IO;
using PlugwiseLib.BLL.BPC;
using PlugwiseLib.UTIL;
namespace PlugwiseLib {
public class plugwiseControl
{
private SerialPort port;
private PlugwiseActions currentAction;
public delegate void PlugwiseDataReceivedEvent(object
sender, System.EventArgs e,
List<PlugwiseMessage> data);
public event PlugwiseDataReceivedEvent
DataReceived;
private PlugwiseReader reader;
/// <summary>
/// Constructor for the Plugwise Control class
/// </summary>
/// <param name="serialPort">The serial port name that the plugwise stick takes</param>
public plugwiseControl(string serialPort)
{
try
{
port = new SerialPort(serialPort);
port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
port.BaudRate = 115200;
currentAction = PlugwiseActions.None;
reader = new PlugwiseReader();
}
catch (Exception e)
{
throw new Exception("Could not connect to plug.");
}
}
/// <summary>
/// This is the method that sends a command to the plugwise plugs.
/// </summary>
/// <param name="mac">The mac adress of the plug that needs to perform the action</param>
/// <param name="action">The action that has to be performed</param>
public void Action(string mac,PlugwiseActions action)
{
try
{
string message = "";
switch (action)
{
case PlugwiseActions.On:
currentAction = PlugwiseActions.On;
message = PlugwiseSerialPortFactory.Create(PlugwiseSerialPortRequest.on,mac);
break;
case PlugwiseActions.Off:
currentAction = PlugwiseActions.Off;
message = PlugwiseSerialPortFactory.Create(PlugwiseSerialPortRequest.off, mac);
break;
case PlugwiseActions.Status:
currentAction = PlugwiseActions.Status;
message = PlugwiseSerialPortFactory.Create(PlugwiseSerialPortRequest.status, mac);
break;
case PlugwiseActions.Calibration:
currentAction = PlugwiseActions.Calibration;
message = PlugwiseSerialPortFactory.Create(PlugwiseSerialPortRequest.calibration, mac);
break;
case PlugwiseActions.powerinfo:
currentAction = PlugwiseActions.powerinfo;
message = PlugwiseSerialPortFactory.Create(PlugwiseSerialPortRequest.powerinfo,mac);
break;
case PlugwiseActions.history:
message = "";
break;
}
if (message.Length > 0)
{
port.WriteLine(message);
Thread.Sleep(10);
}
}
catch (Exception e)
{
throw e;
}
}
/// <summary>
/// This is the method that sends a command to the plugwise plugs that retrieves the history power information
/// </summary>
/// <param name="mac">The mac adress of the plug that needs to perform the action</param>
/// <param name="logId">The id of the history message that has to be retrieved</param>
/// <param name="action">The action that has to be performed this MUST be history</param>
public void Action(string mac,int logId,PlugwiseActions action)
{
string message = "";
switch(action)
{
case PlugwiseActions.history:
currentAction = PlugwiseActions.history;
message = PlugwiseSerialPortFactory.Create(PlugwiseSerialPortRequest.history, MessageHelper.ConvertIntToPlugwiseLogHex(logId), mac);
break;
}
if (message.Length > 0)
{
port.WriteLine(message);
Thread.Sleep(10);
}
}
private void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{// Event for receiving data
string txt = port.ReadExisting();
List<PlugwiseMessage> msg = reader.Read(Regex.Split(txt, "\r\n"));
DataReceived(sender, new System.EventArgs(), msg);
}
/// <summary>
/// This method Opens the connection to the serial port
/// </summary>
public void Open()
{
try
{
if (!port.IsOpen)
{
port.Open();
}
}
catch (System.IO.IOException ex)
{
throw ex;
}
}
/// <summary>
/// This method closes the connection to the serial port
/// </summary>
public void Close()
{
try
{
if (port.IsOpen)
{
port.Close();
}
Thread.Sleep(5);
}
catch (IOException ex)
{
throw ex;
}
}
}
}
I get the exception at this piece (in Visual C# 2008 express)
private void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{// Event for receiving data
string txt = port.ReadExisting();
List<PlugwiseMessage> msg = reader.Read(Regex.Split(txt, "\r\n"));
DataReceived(sender, new System.EventArgs(), msg);
I checked 'msg' but this is filled with so far i can see valid data.
So I don't know why I get the exception.

Do you have any subscribers for plugwiseControl.DataReceived event? A common way to raise event is
var handler = DataReceived;
if(handler != null) handler(sender, EventArgs.Empty, msg);

I think DataReceived event is not initialized, by the calling method.

In .NET, if you raise an event and there are no registered listeners for that event (nothing has done to your event what you do to your port's DataReceived event in the second line of your try {} block in your constructor), it shows up as null, and raises that exception. In your Watch list screenshot, DataReceived is null, which makes me think this is the problem. So:
if (DataReceived != null)
DataReceived(...arguments here...);

How to Read and Write from the Serial Port

I just started learning how to send and receive data from my hardware through the C# GUI.
Can anyone please write a detail how to read data from the serial port?

SerialPort (RS-232 Serial COM Port) in C# .NET
This article explains how to use the SerialPort class in .NET to read and write data, determine what serial ports are available on your machine, and how to send files. It even covers the pin assignments on the port itself.
Example Code:
using System;
using System.IO.Ports;
using System.Windows.Forms;
namespace SerialPortExample
{
class SerialPortProgram
{
// Create the serial port with basic settings
private SerialPort port = new SerialPort("COM1",
9600, Parity.None, 8, StopBits.One);
[STAThread]
static void Main(string[] args)
{
// Instatiate this class
new SerialPortProgram();
}
private SerialPortProgram()
{
Console.WriteLine("Incoming Data:");
// Attach a method to be called when there
// is data waiting in the port's buffer
port.DataReceived += new
SerialDataReceivedEventHandler(port_DataReceived);
// Begin communications
port.Open();
// Enter an application loop to keep this thread alive
Application.Run();
}
private void port_DataReceived(object sender,
SerialDataReceivedEventArgs e)
{
// Show all the incoming data in the port's buffer
Console.WriteLine(port.ReadExisting());
}
}
}

I spent a lot of time to use SerialPort class and has concluded to use SerialPort.BaseStream class instead. You can see source code: SerialPort-source and
SerialPort.BaseStream-source for deep understanding.
I created and use code that shown below.
The core function
public int Recv(byte[] buffer, int maxLen)
has name and works like "well known" socket's recv().
It means that
in one hand it has timeout for no any data and throws TimeoutException.
In other hand, when any data has received,
it receives data either until maxLen bytes
or short timeout (theoretical 6 ms) in UART data flow
.
public class Uart : SerialPort
{
private int _receiveTimeout;
public int ReceiveTimeout { get => _receiveTimeout; set => _receiveTimeout = value; }
static private string ComPortName = "";
/// <summary>
/// It builds PortName using ComPortNum parameter and opens SerialPort.
/// </summary>
/// <param name="ComPortNum"></param>
public Uart(int ComPortNum) : base()
{
base.BaudRate = 115200; // default value
_receiveTimeout = 2000;
ComPortName = "COM" + ComPortNum;
try
{
base.PortName = ComPortName;
base.Open();
}
catch (UnauthorizedAccessException ex)
{
Console.WriteLine("Error: Port {0} is in use", ComPortName);
}
catch (Exception ex)
{
Console.WriteLine("Uart exception: " + ex);
}
} //Uart()
/// <summary>
/// Private property returning positive only Environment.TickCount
/// </summary>
private int _tickCount { get => Environment.TickCount & Int32.MaxValue; }
/// <summary>
/// It uses SerialPort.BaseStream rather SerialPort functionality .
/// It Receives up to maxLen number bytes of data,
/// Or throws TimeoutException if no any data arrived during ReceiveTimeout.
/// It works likes socket-recv routine (explanation in body).
/// Returns:
/// totalReceived - bytes,
/// TimeoutException,
/// -1 in non-ComPortNum Exception
/// </summary>
/// <param name="buffer"></param>
/// <param name="maxLen"></param>
/// <returns></returns>
public int Recv(byte[] buffer, int maxLen)
{
/// The routine works in "pseudo-blocking" mode. It cycles up to first
/// data received using BaseStream.ReadTimeout = TimeOutSpan (2 ms).
/// If no any message received during ReceiveTimeout property,
/// the routine throws TimeoutException
/// In other hand, if any data has received, first no-data cycle
/// causes to exit from routine.
int TimeOutSpan = 2;
// counts delay in TimeOutSpan-s after end of data to break receive
int EndOfDataCnt;
// pseudo-blocking timeout counter
int TimeOutCnt = _tickCount + _receiveTimeout;
//number of currently received data bytes
int justReceived = 0;
//number of total received data bytes
int totalReceived = 0;
BaseStream.ReadTimeout = TimeOutSpan;
//causes (2+1)*TimeOutSpan delay after end of data in UART stream
EndOfDataCnt = 2;
while (_tickCount < TimeOutCnt && EndOfDataCnt > 0)
{
try
{
justReceived = 0;
justReceived = base.BaseStream.Read(buffer, totalReceived, maxLen - totalReceived);
totalReceived += justReceived;
if (totalReceived >= maxLen)
break;
}
catch (TimeoutException)
{
if (totalReceived > 0)
EndOfDataCnt--;
}
catch (Exception ex)
{
totalReceived = -1;
base.Close();
Console.WriteLine("Recv exception: " + ex);
break;
}
} //while
if (totalReceived == 0)
{
throw new TimeoutException();
}
else
{
return totalReceived;
}
} // Recv()
} // Uart

Note that usage of a SerialPort.DataReceived event is optional. You can set proper timeout using SerialPort.ReadTimeout and continuously call SerialPort.Read() after you wrote something to a port until you get a full response.
Moreover, you can use SerialPort.BaseStream property to extract an underlying Stream instance. The benefit of using a Stream is that you can easily utilize various decorators with it:
var port = new SerialPort();
// LoggingStream inherits Stream, implements IDisposable, needed abstract methods and
// overrides needed virtual methods.
Stream portStream = new LoggingStream(port.BaseStream);
portStream.Write(...); // Logs write buffer.
portStream.Read(...); // Logs read buffer.
For more information:
Top 5 SerialPort Tips article by Kim Hamilton, BCL Team Blog
C# await event and timeout in serial port communication discussion on StackOverflow