Develop Reference

set blank ip address or remove ip adddress

I want to set ip address, subnet, gateway & dns; there is no issue in setting up but once the ip address is applied i'm trying to delete the existing gateway, pref dns its not working.
I tried to send a empty string but its always picking up .... (4dots) instead of empty string.
How can i set empty ip address or delete the gateway & pref dns ipaddress using the below method?
Get ip address from textbox usercontrol:
string[] pdns = ipsefpredns.GetIPaddress();
string str_pdns = pdns[0].ToString() + "." + pdns[1].ToString() + "." + pdns[2].ToString() + "." + pdns[3].ToString();
string ipaddressprefdns;
string emptypdns = pdns[0].ToString() + pdns[1].ToString() + pdns[2].ToString() + pdns[3].ToString();
if (pdns == null || pdns.Length ==0) //if the array is empty,null get empty string
{
ipaddressprefdns = emptypdns;
}
else
{
ipaddressprefdns = str_pdns;
}
Method to apply ipaddress:
string fileName = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.System), "netsh");
Process.Start(new ProcessStartInfo(fileName)
{
Arguments = string.Format("interface ip set address \"{0}\" static {1} {2} {3}", nicname, ipaddressstatic, ipaddresssubnet, ipaddressgateway),
CreateNoWindow = true,
WindowStyle = ProcessWindowStyle.Hidden
}).WaitForExit();
Process.Start(new ProcessStartInfo(fileName)
{
Arguments = string.Format("interface ip set dns \"{0}\" static {1} Primary", nicname, ipaddressprefdns),
CreateNoWindow = true,
WindowStyle = ProcessWindowStyle.Hidden
}).WaitForExit();

I found a solution by reading the array then compare withit, pass none to gateway address.
string[] pdns = ipsefpredns.GetIPaddress();
string str_pdns = pdns[0].ToString() + "." + pdns[1].ToString() + "." + pdns[2].ToString() + "." + pdns[3].ToString();
string ipaddressprefdns="";
string prefdnss = UsingLoopStringBuilder(pdns);
if (!String.IsNullOrEmpty(prefdnss))
{
ipaddressprefdns = str_pdns;
}
else
{
ipaddressprefdns = "none";
}
//method to read string array[]
public string UsingLoopStringBuilder(string[] array)
{
var result = new StringBuilder();
foreach (var item in array)
{
result.Append(item);
}
return result.ToString();
}

How to get Client or visitor IP Address:: Despite multiple tries Didn't get solution:

How to get Client or visitor IP Address:: Despite multiple tries Didn't get solution: Below what I tried:
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string ipAddress33 = Request.UserHostAddress.ToString();
string strHostName = System.Net.Dns.GetHostName();
string clientIPAddress22 = System.Net.Dns.GetHostAddresses(strHostName).GetValue(1).ToString();
Response.Write("System.Net.Dns.GetHostAddresses(strHostName).GetValue(1).ToString(); : " + clientIPAddress22 + "<br />");
string ipaddress;
string IP = Request.UserHostAddress;
string clientIPAddress = this.Page.Request.ServerVariables["REMOTE_ADDR"];
string IP2 = Environment.GetEnvironmentVariable("CLIENTNAME");
ipaddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (ipaddress == "" || ipaddress == null)
ipaddress = Request.ServerVariables["REMOTE_ADDR"];
Response.Write("Request.ServerVariables['HTTP_X_FORWARDED_FOR'] : " + ipaddress + "<br />");
Response.Write("Request.UserHostAddress.ToString() : " + ipAddress33 + "<br />");
string stringIpAddress;
stringIpAddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (stringIpAddress == null) //may be the HTTP_X_FORWARDED_FOR is null
{
stringIpAddress = Request.ServerVariables["REMOTE_ADDR"];//we can use REMOTE_ADDR
}
Response.Write("Request.ServerVariables['REMOTE_ADDR'] : " + stringIpAddress + "<br />");
//Get the Host Name
string stringHostName = Dns.GetHostName();
//Get The Ip Host Entry
IPHostEntry ipHostEntries = Dns.GetHostEntry(stringHostName);
//Get The Ip Address From The Ip Host Entry Address List
IPAddress[] arrIpAddress = ipHostEntries.AddressList;
Response.Write("Dns.GetHostName(): " + arrIpAddress[arrIpAddress.Length - 1].ToString());
}
}
This is the results I got:
System.Net.Dns.GetHostAddresses(strHostName).GetValue(1).ToString(); : 190.80.90.75
Request.ServerVariables['HTTP_X_FORWARDED_FOR'] : 190.80.90.225
Request.UserHostAddress.ToString() : 190.80.90.225
Request.ServerVariables['REMOTE_ADDR'] : 190.80.90.225
Dns.GetHostName(): 190.80.90.75
Which is not the correct IP address of the visitor.

according to this answer you can use this :
protected void GetUser_IP()
{
string VisitorsIPAddr = string.Empty;
if (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null)
{
VisitorsIPAddr = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();
}
else if (HttpContext.Current.Request.UserHostAddress.Length != 0)
{
VisitorsIPAddr = HttpContext.Current.Request.UserHostAddress;
}
uip.Text = "Your IP is: " + VisitorsIPAddr;
}

VB.Net Version::
-----------------------------------------------
Shared Sub GetUser_IP()
If HttpContext.Current.Request.ServerVariables("HTTP_X_FORWARDED_FOR") IsNot Nothing Then
VisitorsIPAddr = HttpContext.Current.Request.ServerVariables("HTTP_X_FORWARDED_FOR").ToString()
ElseIf HttpContext.Current.Request.UserHostAddress.Length <> 0 Then
VisitorsIPAddr = HttpContext.Current.Request.UserHostAddress
End If
End Sub

How can I receive only the computer names which are accessible for me at this time?

Windows 7 domain network.
I get the domain computer names:
List<String> compNames = new List<String>();
// If it isn't possible to be connected to a domain
// network then we will receive an exception.
using (DirectoryEntry domainEntry = domain.GetDirectoryEntry())
using (DirectorySearcher searcher = new DirectorySearcher(
domainEntry, "objectClass=computer", new[] { "Name" }))
using (SearchResultCollection resultCollection =
searcher.FindAll()) {
foreach (SearchResult searchResult in resultCollection) {
compNames.Add(searchResult.Properties["Name"][0]
.ToString());
}
}
This code returns also the names of computers which already are not existing many years and the computers which are off. How can I recive only the computer names which are accessible for me at this time? Is it possible?

I recommend you to ping each computer on domain to check their accessibility.
Below function you can use to ping computer:
public String PingTest(string asMac)
{
String lsReturn = "";
try
{
Ping pingreq = new Ping();
PingReply rep = pingreq.Send(asMac);
if (rep.Status == IPStatus.Success)
{
lsReturn = "Success"
return lsReturn;
}
else
{
lsReturn = "Error Pinging " + asMac + " " + rep.Status;
}
}
catch (PingException pEx)
{
lsReturn = "PingException Error Pinging " + asMac + " " + pEx.Message + Environment.NewLine + pEx.StackTrace;
}
catch (NetworkInformationException nEx)
{
lsReturn = "NetworkInformationException Error Pinging " + asMac + " " + nEx.Message + Environment.NewLine + nEx.StackTrace;
}
catch (Exception ex)
{
lsReturn = "Error Pinging " + asMac + " " + ex.Message + Environment.NewLine + ex.StackTrace;
}
return lsReturn;
}

Why does a method that calls Ping.Send() on an invalid URL die with an unhandled exception?

The following method calls Ping.Send(). When I pass an invalid URL, Send() dies and an unhandled exception happens. What is the cause of this?
private void ping()
{
comboBox3.Visible = false;
listBox2.Items.Clear();
// check the url if it is null
if (string.IsNullOrEmpty(textBox1.Text) || textBox1.Text == "")
{
listBox2.Items.Add("Please use valid IP or web address!!");
comboBox3.Visible = false;
coloring_red_tab4();
}
else
{
// do the ping
coloring_green_tab4();
for (int i = 0; i < numericUpDown1.Value; i++)
{
string s;
s = textBox1.Text;
string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
byte[] buffer = Encoding.ASCII.GetBytes(data);
int timeout = 120;
Ping p = new Ping();
PingOptions options = new PingOptions();
options.DontFragment = true;
//pingexception was unhalded (if the url wrong here is the error)
PingReply r = p.Send(s, timeout, buffer, options);
// if it's true url
if (r.Status == IPStatus.Success)
{
listBox2.Items.Add("Ping to " + s.ToString() + "[" + r.Address.ToString() + "]" + " (Successful) "
+ "Bytes =" + r.Buffer.Length + " TTL=" + r.Options.Ttl + " Response delay = " + r.RoundtripTime.ToString() + " ms " + "\n");
label91.Text = r.Address.ToString();
}
else
{
// just to know the ip for the website if they block the icmp protocol
listBox2.Items.Add(r.Status);
IPAddress[] ips;
ips = Dns.GetHostAddresses(textBox1.Text);
foreach (IPAddress ip in ips)
{
label91.Text = ip.ToString();
}
}
}
}
}

The exception is unhandled because you do not handle it. Whenever you call a .Net library method, you need to check its documentation to see what exceptions it throws, and decide which, if any, you want to handle at that level of code. Here is the relevant portion of the documentation for Ping.Send(), which I am including as an image so you will be able to recognize these sections going forward:
Notice that the documentation states that a PingException can occur if
An exception was thrown while sending or receiving the ICMP messages. See the inner exception for the exact exception that was thrown.
Thus it's clear from the documentation that many errors from Ping() will be reported as thrown exceptions rather than reported by setting PingReply.Status != IPStatus.Success. So you need to modify your code to be something like the following:
public static bool TryPing(string hostNameOrAddress, out string pingStatusMessage, out string pingAddressMessage)
{
if (String.IsNullOrWhiteSpace(hostNameOrAddress))
{
pingStatusMessage = "Missing host name";
pingAddressMessage = "";
return false;
}
var data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
var buffer = Encoding.ASCII.GetBytes(data);
var timeout = 120;
using (var p = new Ping())
{
var options = new PingOptions();
options.DontFragment = true;
try
{
var r = p.Send(hostNameOrAddress, timeout, buffer, options);
if (r.Status == IPStatus.Success)
{
pingStatusMessage = "Ping to " + hostNameOrAddress.ToString() + "[" + r.Address.ToString() + "]" + " (Successful) "
+ "Bytes =" + r.Buffer.Length + " TTL=" + r.Options.Ttl + " Response delay = " + r.RoundtripTime.ToString() + " ms " + "\n";
pingAddressMessage = r.Address.ToString();
return true;
}
else
{
// just to know the ip for the website if they block the icmp protocol
pingStatusMessage = r.Status.ToString();
var ips = Dns.GetHostAddresses(hostNameOrAddress);
pingAddressMessage = String.Join(",", ips.Select(ip => ip.ToString()));
return false;
}
}
catch (PingException ex)
{
pingStatusMessage = string.Format("Error pinging {0}: {1}", hostNameOrAddress, (ex.InnerException ?? ex).Message);
pingAddressMessage = hostNameOrAddress;
return false;
}
}
}
Here I have extracted a utility method from the user interface code and also properly disposed of the Ping instance after it is no longer needed.
Then
TryPing(#"www.google.com", out pingStatusMessage, out pingAddressMessage);
Gives
Ping to www.google.com[146.115.8.83] (Successful) Bytes =32 TTL=62 Response delay = 8 ms
While
TryPing(#"www.kdjf98rglkfgjldkfjgdl;fge8org.com", out pingStatusMessage, out pingAddressMessage);
Gives
Error pinging www.kdjf98rglkfgjldkfjgdl;fge8org.com: No such host is known

Null Reference : Object reference not set to an instance of an object

I have a code for serial communication, with this code im sending values from textboxes to an device or when im testing to another PC. But when I press my "Program" button I get this error.
System.NullReferenceException was unhandled
Object reference not set to an instance of an object.
And i can catch the exception with an try catch but then i wont send my values to the device connected to my port.
This is my code:
public partial class MainForm : Form
{
private Settings _settings;
private SettingsIniFile _settingsIniFile = new SettingsIniFile();
private StringList _baudratelist = new StringList();
private StringList _systemPorts = new StringList();
private StringList _comportList = new StringList();
private Timer _comtimer = new Timer();
private ComPort _comport;
public MainForm()
{
InitializeComponent();
SetBaudrate();
LoadSettings(false);
LoadTextBoxes();
LoadComportName();
_comtimer.Tick += OnComtimerOnTick;
_comtimer.Interval = 2000;
_comtimer.Start();
LoadComportName();
Thread.Sleep(1000);
var portname = GetCurrentComPort();
if (portname != null)
{
_comport = new ComPort("COM6", 9600);
}
//var portname = GetCurrentComPort();
}
private String GetCurrentComPort()
{
int index = _comPortComboBox.SelectedIndex;
if (index < 0)
return null;
return _comportList[index];
}
private void OnComtimerOnTick(object sender, EventArgs args)
{
foreach (var item in SerialPort.GetPortNames())
{
if (!_systemPorts.Contains(item))
{
_comtimer.Stop();
_systemPorts.Add(item);
LoadComportName();
//MessageBox.Show("The new device is connected to" + item);
_comtimer.Start();
}
}
}
private void LoadSettings(bool defaults)
{
SettingsIniFile iniFile = new SettingsIniFile();
_settings = iniFile.LoadSettings(defaults);
}
private void SaveSettings()
{
SaveTextBoxes();
_settingsIniFile.Save(_settings);
}
private void LoadTextBoxes()
{
//ACR
_startRemovalTextBox.Text = _settings.AcrStartRemoval11;
_removalTimeTextBox.Text = _settings.AcrRemovalTime12;
_removalDelayTextBox.Text = _settings.AcrRemovalDelay13;
//CLEANING
_durCleaningTextbox.Text = _settings.CleanDurCleaning21;
_timeValveOnTextbox.Text = _settings.CleanTimeValveOn22;
_timeValveOffTextBox.Text = _settings.CleanTimeValveOff23;
//CALIBRATE
_contentLeftTextBox.Text = _settings.CalibrateContentLeft31;
_calibrateLeftTextBox.Text = _settings.CalibrateCalibrateLeft33;
_contentRightTextBox.Text = _settings.CalibrateContentRight32;
_calibrateRightTextBox.Text = _settings.CalibrateCalibrateRight34;
//CONDUCTIVITY
_factorLeftTextBox.Text = _settings.ConductFactorLeft41;
_offsetLeftTextBox.Text = _settings.ConductOffsetleft42;
_factorRightTextBox.Text = _settings.ConductFactorRight43;
_offsetRightTextBox.Text = _settings.ConductOffsetRight44;
_levelLeftTextBox.Text = _settings.ConductLevelLeft45;
_levelRightTextBox.Text = _settings.ConductLevelRight46;
//GENERAL
_typeOfValveTextBox.Text = _settings.GeneralTypeOfValve51;
_indicatorTextBox.Text = _settings.GeneralIndicator52;
_inverseOutputTextBox.Text = _settings.GeneralInverseOutput53;
_restartTimeTextBox.Text = _settings.GeneralRestartTime54;
_waterTimeTextBox.Text = _settings.GeneralWaterTime55;
_gateDelayTextbox.Text = _settings.GeneralGateDelay56;
//PULSATION
_pulsationTextBox.Text = _settings.PulsationPulsationPm61;
_ratioFrontTextBox.Text = _settings.PulsationSrRatioFront62;
_ratioBackTextBox.Text = _settings.PulsationSrRatioBack63;
_stimulationTextBox.Text = _settings.PulsationStimulationPm64;
_stimFrontTextBox.Text = _settings.PulsationSrStimFront65;
_stimBackTextBox.Text = _settings.PulsationSrStimBack66;
_stimulationDurTextBox.Text = _settings.PulsationStimulationDur67;
//return _settings;
}
private void SaveTextBoxes()
{
//ACR
_settings.AcrStartRemoval11 = _startRemovalTextBox.Text;
_settings.AcrRemovalTime12 = _removalTimeTextBox.Text;
_settings.AcrRemovalDelay13 = _removalDelayTextBox.Text;
//CLEANING
_settings.CleanDurCleaning21 = _durCleaningTextbox.Text;
_settings.CleanTimeValveOn22 = _timeValveOnTextbox.Text;
_settings.CleanTimeValveOff23 = _timeValveOffTextBox.Text;
//CALIBRATE
_settings.CalibrateContentLeft31 = _contentLeftTextBox.Text;
_settings.CalibrateCalibrateLeft33 = _calibrateLeftTextBox.Text;
_settings.CalibrateContentRight32 = _contentRightTextBox.Text;
_settings.CalibrateCalibrateRight34 = _calibrateRightTextBox.Text;
//CONDUCTIVITY
_settings.ConductFactorLeft41 = _factorLeftTextBox.Text;
_settings.ConductOffsetleft42 = _offsetLeftTextBox.Text;
_settings.ConductFactorRight43 = _factorRightTextBox.Text;
_settings.ConductOffsetRight44 = _offsetRightTextBox.Text;
_settings.ConductLevelLeft45 = _levelLeftTextBox.Text;
_settings.ConductLevelRight46 = _levelRightTextBox.Text;
//GENERAL
_settings.GeneralTypeOfValve51 = _typeOfValveTextBox.Text;
_settings.GeneralIndicator52 = _indicatorTextBox.Text;
_settings.GeneralInverseOutput53 = _inverseOutputTextBox.Text;
_settings.GeneralRestartTime54 = _restartTimeTextBox.Text;
_settings.GeneralWaterTime55 = _waterTimeTextBox.Text;
_settings.GeneralGateDelay56 = _gateDelayTextbox.Text;
//PULSATION
_settings.PulsationPulsationPm61 = _pulsationTextBox.Text;
_settings.PulsationSrRatioFront62 = _ratioFrontTextBox.Text;
_settings.PulsationSrRatioBack63 = _ratioBackTextBox.Text;
_settings.PulsationStimulationPm64 = _stimulationTextBox.Text;
_settings.PulsationSrStimFront65 = _stimFrontTextBox.Text;
_settings.PulsationSrStimBack66 = _stimBackTextBox.Text;
_settings.PulsationStimulationDur67 = _stimulationDurTextBox.Text;
}
private void DefaultSettingButtonClick(object sender, System.EventArgs e)
{
LoadSettings(true);
LoadTextBoxes();
SaveSettings();
LoadComportName();
}
private void SendSettingsButtonClick(object sender, System.EventArgs e)
{
var availablePorts = _systemPorts;
if (availablePorts != null && availablePorts.Any())
{
SaveSettings();
SendMessageTest();
}
else
{
_comPortComboBox.Text = "No Ports are available";
}
}
private void LoadComportName()
{
var availablePorts = _systemPorts;
_comPortComboBox.DataSource = null;
if (availablePorts != null && availablePorts.Any())
{
_comPortComboBox.DataSource = availablePorts;
}
else
{
_comPortComboBox.Text = "No Ports are available";
}
}
private void SetBaudrate()
{
_baudratelist.Add("4600");
_baudratelist.Add("9600");
_baudratelist.Add("19200");
}
private void SendMessageTest()
{
var Acrcontent = "[" + _acrNameLabel.Text + "]" + "\r\n" + _acrIdLabel11.Text + _startRemovalTextBox.Text + "\r\n"
+ _acrIdLabel12.Text + _removalTimeTextBox.Text + "\r\n" + _acrIdLabel13.Text +
_removalDelayTextBox.Text + "\r\n";
var Cleaningcontent ="["+ _cleaningNamelLabel.Text+"]" +"\r\n"+_cleaningIdLabel21.Text+
_durCleaningTextbox.Text + "\r\n"+ _cleaningLabelId22.Text+
_timeValveOnTextbox.Text + "\r\n"+ _cleaningLabelId23.Text+_timeValveOffTextBox.Text+"\r\n";
var Calibratecontent = "[" +_calibrateNameLabel.Text+ "]"+"\r\n"+_calibrateIDLabel31.Text+_contentLeftTextBox.Text+
"\r\n"+ _calibrateIDLabel32.Text+_calibrateLeftTextBox.Text+"\r\n"+_calibrateIDLabel33.Text+_contentRightTextBox.Text+
"\r\n" + _calibrateIDLabel34.Text + _calibrateRightTextBox.Text + "\r\n";
var Conductcontent = "[" + _conductName.Text + "]" + "\r\n" + _conductIdLabel41.Text + _factorLeftTextBox.Text +
"\r\n"
+ _conductIdLabel42.Text + _offsetLeftTextBox.Text + "\r\n" + _conductIdLabel43.Text +
_factorRightTextBox.Text + "\r\n"
+ _conductIdLabel44.Text + _offsetRightTextBox.Text + "\r\n" + _conductIdLabel45.Text +
_levelLeftTextBox.Text + "\r\n"
+ _conductIdLabel46.Text + _levelRightTextBox.Text + "\r\n";
var Generalcontent = "[" + _generalName.Text + "]" + "\r\n" + _generalIdLabel51.Text + _typeOfValveTextBox.Text +
"\r\n" +
_generalIdLabel52.Text + _indicatorTextBox.Text + "\r\n" + _generalIdLabel53.Text +
_inverseOutputTextBox.Text +
"\r\n" + _generalIdLabel54.Text + _restartTimeTextBox.Text + "\r\n" +
_generalIdLabel55.Text + _waterTimeTextBox.Text +
"\r\n" + _generalIdLabel56.Text + _gateDelayTextbox.Text + "\r\n";
var Pulsationcontent = "[" + _pulsationName.Text + "]" + "\r\n" + _pulsationIdLabel61.Text +
_pulsationTextBox.Text + "\r\n" +
_pulsationIdLabel62.Text + _ratioFrontTextBox.Text + "\r\n" +
_pulsationIdLabel63.Text + _ratioBackTextBox.Text + "\r\n" +
_pulsationIdLabel64.Text + _stimulationTextBox.Text + "\r\n" +
_pulsationIdLabel65.Text + _stimFrontTextBox.Text + "\r\n" +
_pulsationIdLabel66.Text + _stimBackTextBox.Text + "\r\n" + _pulsationIdLabel67.Text +
_stimulationDurTextBox.Text + "\r\n";
byte[] array = ComPort.StringToBytes(2+"\r\n"+Acrcontent+"\r\n"+Cleaningcontent + "\r\n" + Calibratecontent+"\r\n"+Conductcontent+"\r\n"+Generalcontent+"\r\n"+Pulsationcontent+3);
try
{
_comport.WriteBytes(array);
}
catch(Exception exc)
{
MessageBox.Show("Error {1}: "+ exc);
}
try
{
_comport.ReadBytes(array, array.Length, 1000);
}
catch(Exception exc)
{
MessageBox.Show("Error {2}" + exc);
}
//string result = Encoding.ASCII.GetString(array);
//MessageBox.Show(result);
}
}
This is my code for the communication:
namespace Communication
{
public class ComPort
{
private readonly SerialPort _serialPort;
public ComPort(string portname, int baudRate)
{
_serialPort = new SerialPort();
_serialPort.PortName = portname; <-----
_serialPort.BaudRate = baudRate;
_serialPort.StopBits = StopBits.One;
_serialPort.DataBits = 8;
_serialPort.Parity = Parity.None;
_serialPort.Handshake = Handshake.None;
// _serialPort.WriteBufferSize = 1;
_serialPort.DtrEnable = true;
_serialPort.RtsEnable = true;
_serialPort.Open();
_serialPort.ReadTimeout = 20000;
_serialPort.WriteTimeout = 20000;
}
public void Clear()
{
while (ReadByte() != -1)
continue;
}
private byte[] _array = new byte[] {0};
public void WriteByte(byte value)
{
_array[0] = value;
_serialPort.Write(_array, 0, 1);
// _serialPort.BaseStream.WriteByte(value);
_serialPort.BaseStream.Flush();
}
public void WriteBytes(byte[] array)
{
_serialPort.Write(array, 0, array.Length);
}
public void WriteBytes(byte[] array, int index, int length )
{
_serialPort.Write(array, index, length);
}
private int _readTimeOut = -1;
public int ReadByte(int timeOut = 200)
{
if (timeOut != _readTimeOut)
_serialPort.ReadTimeout = _readTimeOut = timeOut;
try
{
//return _serialPort.BaseStream.ReadByte();
return _serialPort.ReadByte();
// _serialPort.Read(array, 0, 1);
// return array[0];
}
catch (TimeoutException)
{
return -1;
}
}
public int ReadBytes(byte[] array, int length, int timeOut = 200)
{
if (timeOut != _readTimeOut)
_serialPort.ReadTimeout = _readTimeOut = timeOut;
try
{
//return _serialPort.BaseStream.ReadByte();
int bytesRead = 0;
while ( bytesRead < length )
bytesRead += _serialPort.Read(array, bytesRead, length - bytesRead);
// _serialPort.Read(array, 0, 1);
// return array[0];
return bytesRead;
}
catch (TimeoutException)
{
return -1;
}
}
/// <summary>
/// sends string followed by CR - LF
/// </summary>
/// <param name="line"></param>
public void WriteLine(String line)
{
WriteBytes(StringToBytes(line + "\r\n"));
}
public static byte[] StringToBytes(string input)
{
return Encoding.ASCII.GetBytes(input);
}
public void Close()
{
try
{
_serialPort.DtrEnable = false;
_serialPort.RtsEnable = false;
_serialPort.Close();
}
catch(IOException)
{
}
}
public bool Dtr
{
get { return _serialPort.DtrEnable; }
set { _serialPort.DtrEnable = value; }
}
public bool Rts
{
get { return _serialPort.RtsEnable; }
set { _serialPort.RtsEnable = value; }
}
}
}
Can someone explain to me what the problem is?
Thanks in advance
Possible anwser:
InitializeComponent();
SetBaudrate();
LoadSettings(false);
LoadTextBoxes();
LoadComportName();
_comtimer.Tick += OnComtimerOnTick;
_comtimer.Interval = 2000;
_comtimer.Start();
LoadComportName();
Thread.Sleep(1000);
var portname = GetCurrentComPort();
_comport = new ComPort("COM6", 9600);
But when i do this another error comes around the corner:
Value cannot be null.
Parameter name: PortName
This comes in the second piece of code where the arrow is.

Probably there is not comport selected at startup, so the _comport never gets created, you should check if the comport is created before you use is: if (_comport != null) ...
Update:
I think you should create a button instead of default connecting on a combobox selection change.
public void buttonConnect_Click(object sender, EventArgs e)
{
// check if the comport is created, else show a message and return,
TryDisconnect();
var portname = GetCurrentComPort();
if (portname == null)
return;
try
{
_comport = new ComPort(portname, 9600);
}
catch(Exception exception)
{
// try to create a better message here :-)
MessageBox.Show("Something went wrong....");
}
}
public void buttonDisconnect_Click(object sender, EventArgs e)
{
TryDisconnect();
}
public void TryDisconnect()
{
if( _comport != null)
{
_comport.Dispose();
_comport = null;
}
}
Also for this:
private void SendSettingsButtonClick(object sender, System.EventArgs e)
{
// check the _comPort instance first, if not assigned, leave a message..
if(_comPort == null)
{
MessageBox.Show("The comport is not initialized");
return;
}
var availablePorts = _systemPorts;
if (availablePorts != null && availablePorts.Any())
{
SaveSettings();
SendMessageTest();
}
else
{
_comPortComboBox.Text = "No Ports are available";
}
}
I got a tip for you, try to separate the markup/construction of the message, here how you could do.
I did not change all the code, only some examples:
I would create a struct/class to hold all information
public struct AcrContentInfo
{
public string AcrName;
public string AcrId11;
public string StartRemoval;
public string AcrId12;
public string RemovalTime;
public string AcrId13;
public string RemovalDelay;
// markup the information:
public override string ToString()
{
return string.Format(
"[{0}]\r\n{1}{2}\r\n{3}{4}\r\n{5}{6}\r\n",
AcrName,
AcrId11, StartRemoval,
AcrId12, RemovalTime,
AcrId13, RemovalDelay);
}
}
private void SendMessageTest()
{
// Instead of:
//var Acrcontent = "[" + _acrNameLabel.Text + "]" + "\r\n" + _acrIdLabel11.Text + _startRemovalTextBox.Text + "\r\n"
// + _acrIdLabel12.Text + _removalTimeTextBox.Text + "\r\n" + _acrIdLabel13.Text +
// _removalDelayTextBox.Text + "\r\n";
// I would use this instead, this way it wil be easier to maintain different versions.
// The code using the struct isn't responsible for markup
// Create the struct and fillin the fields.
AcrContentInfo acrContentInfo = new AcrContentInfo
{
AcrName = _acrNameLabel.Text,
AcrId11 = _acrIdLabel11.Text,
StartRemoval = _startRemovalTextBox.Text,
AcrId12 = _acrIdLabel12.Text,
RemovalTime = _removalTimeTextBox.Text,
AcrId13 = _acrIdLabel13.Text,
RemovalDelay = _removalDelayTextBox.Text
};
// if there is a new version of the protocol, you can create something like this
// AcrContentInfoV2 acrContentInfo = new AcrContentInfoV2
// call the tostring, (create a markup)
var Acrcontent = acrContentInfo.ToString();
// --- old code ---
var Cleaningcontent = "[" + _cleaningNamelLabel.Text + "]" + "\r\n" + _cleaningIdLabel21.Text +
_durCleaningTextbox.Text + "\r\n" + _cleaningLabelId22.Text +
_timeValveOnTextbox.Text + "\r\n" + _cleaningLabelId23.Text + _timeValveOffTextBox.Text + "\r\n";
var Calibratecontent = "[" + _calibrateNameLabel.Text + "]" + "\r\n" + _calibrateIDLabel31.Text + _contentLeftTextBox.Text +
"\r\n" + _calibrateIDLabel32.Text + _calibrateLeftTextBox.Text + "\r\n" + _calibrateIDLabel33.Text + _contentRightTextBox.Text +
"\r\n" + _calibrateIDLabel34.Text + _calibrateRightTextBox.Text + "\r\n";
var Conductcontent = "[" + _conductName.Text + "]" + "\r\n" + _conductIdLabel41.Text + _factorLeftTextBox.Text +
"\r\n"
+ _conductIdLabel42.Text + _offsetLeftTextBox.Text + "\r\n" + _conductIdLabel43.Text +
_factorRightTextBox.Text + "\r\n"
+ _conductIdLabel44.Text + _offsetRightTextBox.Text + "\r\n" + _conductIdLabel45.Text +
_levelLeftTextBox.Text + "\r\n"
+ _conductIdLabel46.Text + _levelRightTextBox.Text + "\r\n";
var Generalcontent = "[" + _generalName.Text + "]" + "\r\n" + _generalIdLabel51.Text + _typeOfValveTextBox.Text +
"\r\n" +
_generalIdLabel52.Text + _indicatorTextBox.Text + "\r\n" + _generalIdLabel53.Text +
_inverseOutputTextBox.Text +
"\r\n" + _generalIdLabel54.Text + _restartTimeTextBox.Text + "\r\n" +
_generalIdLabel55.Text + _waterTimeTextBox.Text +
"\r\n" + _generalIdLabel56.Text + _gateDelayTextbox.Text + "\r\n";
var Pulsationcontent = "[" + _pulsationName.Text + "]" + "\r\n" + _pulsationIdLabel61.Text +
_pulsationTextBox.Text + "\r\n" +
_pulsationIdLabel62.Text + _ratioFrontTextBox.Text + "\r\n" +
_pulsationIdLabel63.Text + _ratioBackTextBox.Text + "\r\n" +
_pulsationIdLabel64.Text + _stimulationTextBox.Text + "\r\n" +
_pulsationIdLabel65.Text + _stimFrontTextBox.Text + "\r\n" +
_pulsationIdLabel66.Text + _stimBackTextBox.Text + "\r\n" + _pulsationIdLabel67.Text +
_stimulationDurTextBox.Text + "\r\n";
// instad of:
//byte[] array = ComPort.StringToBytes(2+"\r\n"+Acrcontent+"\r\n"+Cleaningcontent + "\r\n" + Calibratecontent+"\r\n"+Conductcontent+"\r\n"+Generalcontent+"\r\n"+Pulsationcontent+3);
// I always try not to make very long lines of code.
// A stringbuilder is much more efficient building strings.
// I would:
StringBuilder sb = new StringBuilder();
sb.AppendLine("2");
sb.AppendLine("Acrcontent");
sb.AppendLine("Cleaningcontent");
sb.AppendLine("Calibratecontent");
sb.AppendLine("Conductcontent");
sb.AppendLine("Generalcontent");
sb.AppendLine("Pulsationcontent");
sb.AppendLine("3");
// why make the comport class responsible for the encoding type. _ComPort.StringToBytes_
byte[] array = Encoding.UTF8.GetBytes(sb.ToString());
try
{
_comport.WriteBytes(array);
// only read when write was succeed?
_comport.ReadBytes(array, array.Length, 1000);
}
catch (Exception exc)
{
MessageBox.Show("Error {1}: " + exc);
}
}
These are only my ideas, and meant to be constructive. (other point of view) Happy codeing..

You have to instantiate _comport before calling a method or accessing a property on it.
maybe in
var portname = GetCurrentComPort();
if (portname != null)
{
_comport = new ComPort("COM6", 9600);
}
portname is null then _comport not instantiated. you can trace it and check that if it has a value or not.

Yes assign a value to _comport like
_comport=null;