I have a form an one button on it,
below is very really simple my code:
private void ConnectDb()
{
try
{
connect = new OleDbConnection();
connect.ConnectionString = #"Provider=Microsoft.ACE.OLEDB.15.0;Data Source=MySong.accdb;Persist Security Info=false;";
connect.Open();
statusText.Text = "Database connected";
command = connect.CreateCommand();
}
catch (Exception)
{
statusText.Text = "ERROR::Database failed";
}
}
private void CloseConnectDb()
{
if (connect != null)
{
connect.Close();
statusText.Text = "Database Closed";
}
}
private void btnTambah_Click(object sender, EventArgs e)
{
DateTime tanggal = DateTime.Today;
Band = txtArtis.Text;
Title = txtJudul.Text;
this.ConnectDb();
command.CommandText = "INSERT INTO TableLagu (Tanggal, Artis, Title, Status) VALUES ('" + tanggal + "', '" + Band + "', '" + Title + "', 'Belum ada')";
if (command.ExecuteNonQuery() != 0) //executenonquery returns number of row affected
{
statusText.Text = "ADD--Data Success inserted";
txtArtis.Text = "";
txtJudul.Text = "";
}
else statusText.Text = "ERROR::Insert failed";
this.CloseConnectDb();
}
When i click on my 'btnTambah' button, it always say "object reference not set to an instance of an object" and display "ERROR::Database failed" on its statusText.
any solution??
i think this code doesn't run while try to call ConnectDb method.
you can see my connection string
Provider=Microsoft.ACE.OLEDB.15.0;
actually, when i creating it, i have microsoft access database 2013 installed on my machine. it works good.
now, i'm trying to run my application on my friends computer that microsoft access installed version 2007. and got an error like above.
Related
I am working on a Xamarin App where I am facing an issue.
Case 1:
Mode: Debug
Error: System.NullReferenceException: 'Object reference not set to an instance of an object'
Explanation:
No value is being set and passed to ViewModel, Controller.
Even I tried setting static values to variables and parameters.
LoginModel logtest = new LoginModel();
logtest.Username = "Test#user.com"; //uName;
logtest.Password = "2342534"; //pWord;
Tried solution:
In the beginning, I tried many different solutions nothing worked.
Then I create a new project and moved all the code to the new project, then it started working.
Case 2:
Mode: release
Now the same issue I am getting in release mode.
No value is being set and passed to ViewModels and Controller.
I have already tried moving code to a new project.
How can I resolve this? I am not sure is this a Visual studio issue or Xamarin issue or Apple.
I have tried updating Visual Studio enterprise 2019 and Xcode on Mac.
Deleted and recreated Provisioning Profiles and Signing Identities.
Code From LoginPage.xaml.cs
private async void LoginButtonClicked(object sender, EventArgs e)
{
await ((LoginViewModel)BindingContext).Login();
}
protected async override void OnAppearing()
{
//App.Current.MainPage = new Navigation(new DashboardPage());
//load the login page
Device.BeginInvokeOnMainThread(() =>
{
try
{
((LoginViewModel)BindingContext).IsLoading = false;
((LoginViewModel)BindingContext).RememberMe = DeviceStorage.RememberMe;
if (DeviceStorage.RememberMe == true)
{
((LoginViewModel)BindingContext).UserName = "Test#user.ca"; //Trying set static values here
((LoginViewModel)BindingContext).Password = "password"; //Trying set static values here
}
//RememberMeToggle.Toggled += switcher_Toggled;
((LoginViewModel)BindingContext).Load();
}
catch (Exception ex)
{
//logger.Error(App.LogPrefix() + "Error opening Navigation Page: " + ex.Message);
Console.WriteLine(App.LogPrefix() + "Error opening Load(): " + ex.Message);
}
});
}
Code from LoginViewModel.cs
public async Task Login()
{
IsLoading = true;
await TokenController.GetAuthorizationToken(UserName, Password);
}
Code from TokenController.cs
public static async Task GetAuthorizationToken(string uName, string pWord)
{
bool tokenReturned = false;
string tokenGetResponse = string.Empty;
// Have tried setting them static values as well
LoginModel logtest = new LoginModel();
logtest.Username = uName;
logtest.Password = pWord;
logtest.AppType = Constants.AppDetails.APP_CODE;
logtest.SystemCode = Constants.AppDetails.SYSTEM_CODE;
logtest.Push.PushSystem = PushAddressModel.PushSystemCode.FireBase;
logtest.Push.Address = ((App)App.Current).PushNotificationToken;
logtest.Push.AppCode = Constants.AppDetails.APP_CODE;
string uri = URI.message_Chat_Endpoint;
(tokenReturned, tokenGetResponse) = await ApiFunctions.Post(logtest, URI.token_Endpoint, false);
if (tokenReturned)
{
try
{
//deserialize the return object
TokenModel token = JsonConvert.DeserializeObject<TokenModel>(tokenGetResponse);
((App)App.Current).token = token;
}
catch (Exception ex)
{
Console.WriteLine("Error: " + ex.Message);
//logger.Error(App.LogPrefix() + "Error: " + ex.Message);
}
Console.WriteLine("Profile Token loaded: " + ((App)App.Current).token.access_token);
}
else
{
Console.WriteLine("Error: Error loading profile token ");
//logger.Error(App.LogPrefix() + "Error loading profile token");
}
}
It is necessary to replace the direct connection to the database with API.
I use this code to directly connect to MySQL db and change pin information:
public async void DatabaseConnection(List<CustomPin> pins)
{
string ConnectionString = "server=192.168.0.1;uid=user;port=4444;pwd=pass;database=dbName;";
MySqlConnection Conn = new MySqlConnection(ConnectionString);
try
{
Conn.Open();
string query = "SELECT * FROM sel_alert_level s;";
MySqlCommand myCommand = new MySqlCommand(query, Conn);
MySqlDataReader myReader;
myReader = myCommand.ExecuteReader();
try
{
while (myReader.Read())
{
int codeNum = myReader.GetInt32(4);
int level = myReader.GetInt32(3);
int mapCode = myReader.GetInt32(0);
foreach (var item in pins)
{
if (item.CodeNum == codeNum)
{
item.AlertLevel = level;
item.CodeNum = codeNum;
item.MapCode = mapCode;
//await DisplayAlert("Alert", mapCode.ToString(), "ok");
}
}
//await DisplayAlert("Database Connection", "Connected .." + Environment.NewLine + myReader.GetInt32(0) + Environment.NewLine + myReader.GetString(1) + Environment.NewLine + myReader.GetString(2) + Environment.NewLine + myReader.GetInt32(3) + Environment.NewLine + myReader.GetInt32(4), "OK");
}
}
finally
{
myReader.Close();
Conn.Close();
}
}
catch (Exception ex)
{
await DisplayAlert("Database Connection", "Not Connected ..." + Environment.NewLine + ex.ToString(), "OK");
}
}
With this code I successfully update the pin information.
Now I create the same method with API Response and what to do the same like DatabaseConnection(); just try to update the information, but not work for me :(
public async void APIConnection(List<CustomPin> pins)
{
try
{
WaterBindingData waterData = await _restServiceData.GetWaterDataForecast(GenerateRequestUriStations(Constants.EndPoint), GenerateRequestUri(Constants.EndPoint));
foreach (var water in waterData.WaterStation.Stations)
{
foreach (var item in pins)
{
if (item.CodeNum == water.CodeNum)
{
item.AlertLevel = water.AlertLevelStation;
item.CodeNum = water.CodeNum;
item.MapCode = water.MapCode;
}
}
}
}
catch (Exception ex)
{
await DisplayAlert("Data Alert", "Error:" + Environment.NewLine + ex.ToString(), "OK");
}
}
I not have any errors here. waterData come with the data, but data not changed in the pins.. I don't know why...
And Now my information are not changed ..
MapCode and other variables not changed.
I call this two methods in the constructor like that:
DatabaseConnection(customMap.CustomPins);
APIConnection(customMap.CustomPins);
So... When I start the project I receive message like this:
/Applications/Visual Studio.app/Contents/Resources/lib/monodevelop/bin/MSBuild/Current/bin/Microsoft.Common.CurrentVersion.targets(5,5): Warning MSB3276: Found conflicts between different versions of the same dependent assembly. Please set the "AutoGenerateBindingRedirects" property to true in the project file. For more information, see http://go.microsoft.com/fwlink/?LinkId=294190. (MSB3276) (MaritsaTundzhaForecast.iOS)
And I check this link but I not have properties option, because I use mac. I have only options on the projects.
Is it possible that this does not change the content in the pins аnd what would be the reason it didn't work ?
I checked the if statement in the loop and she work:
Since it is an asynchronous method , I suggest you try to assign customMap.CustomPins in APIConnection method .
Something like that
//constructor
List<CustomPin> pins = xxxxx;
APIConnection(pins);
public async void APIConnection(List<CustomPin> pins)
{
try
{
WaterBindingData waterData = await _restServiceData.GetWaterDataForecast(GenerateRequestUriStations(Constants.EndPoint), GenerateRequestUri(Constants.EndPoint));
foreach (var water in waterData.WaterStation.Stations)
{
foreach (var item in pins)
{
if (item.CodeNum == water.CodeNum)
{
item.AlertLevel = water.AlertLevelStation;
item.CodeNum = water.CodeNum;
item.MapCode = water.MapCode;
}
}
}
customMap.CustomPins = pins; //assign the value in this line
}
catch (Exception ex)
{
await DisplayAlert("Data Alert", "Error:" + Environment.NewLine + ex.ToString(), "OK");
}
}
I am trying to extract header and body information from email, the following code retrieves the header and body in their raw form. I have an email object that contains the fields from, subject, date, and body. I would like to extract these values from the email and assign them to the email object. How do I get around it? I have tried several ways like getting the header info and using a streamReader.ReadLine() to get a line but I got illegal path exceptions. I know I can use a library but I need to achieve it this way.
What I mean is this, IMAP command returns header information. And I want to extract subject value, date value, sender e-amil, etc. and assign them to my email objects corresponding values like
emailObject.subject = "subjectValue"
public class Imap
{
static void Main(string[] args)
{
try
{
path = Environment.CurrentDirectory + "\\emailresponse.txt";
if (System.IO.File.Exists(path))
System.IO.File.Delete(path);
sw = new System.IO.StreamWriter(System.IO.File.Create(path));
tcpc = new System.Net.Sockets.TcpClient("imap.gmail.com", 993);
ssl = new System.Net.Security.SslStream(tcpc.GetStream());
ssl.AuthenticateAsClient("imap.gmail.com");
receiveResponse("");
Console.WriteLine("username : ");
username = Console.ReadLine();
Console.WriteLine("password : ");
password = Console.ReadLine();
receiveResponse("$ LOGIN " + username + " " + password + " \r\n");
Console.Clear();
receiveResponse("$ LIST " + "\"\"" + " \"*\"" + "\r\n");
receiveResponse("$ SELECT INBOX\r\n");
receiveResponse("$ STATUS INBOX (MESSAGES)\r\n");
Console.WriteLine("enter the email number to fetch :");
int number = int.Parse(Console.ReadLine());
Console.WriteLine("*************Header************");
Console.WriteLine("");
// receiveResponse("$ FETCH " + number + " body[header]\r\n");
// BODY.PEEK[HEADER.FIELDS (SUBJECT)]
// StringBuilder sb = receiveResponse("$ FETCH " + number + " BODY.PEEK[HEADER.FIELDS (From Subject Date)]\r\n");
StringBuilder sb= receiveResponse("$ FETCH " + number + " body.peek[header]\r\n");
Console.WriteLine(sb);
Console.WriteLine("");
Console.WriteLine("Body");
sb = new StringBuilder();
sb=receiveResponse("$ FETCH " + number + " body[text]\r\n");
System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
byte[] serverbuff = new Byte[1024];
int count = 0;
string retval = enc.GetString(serverbuff, 0, count);
Console.WriteLine(sb.ToString());
receiveResponse("$ LOGOUT\r\n");
}
catch (Exception ex)
{
Console.WriteLine("error: " + ex.Message);
}
finally
{
if (sw != null)
{
sw.Close();
sw.Dispose();
}
if (ssl != null)
{
ssl.Close();
ssl.Dispose();
}
if (tcpc != null)
{
tcpc.Close();
}
}
Console.ReadKey();
}
static StringBuilder receiveResponse(string command)
{
sb = new StringBuilder();
try
{
if (command != "")
{
if (tcpc.Connected)
{
dummy = Encoding.ASCII.GetBytes(command);
ssl.Write(dummy, 0, dummy.Length);
}
else
{
throw new ApplicationException("TCP CONNECTION DISCONNECTED");
}
}
ssl.Flush();
buffer = new byte[2048];
bytes = ssl.Read(buffer, 0, 2048);
sb.Append(Encoding.ASCII.GetString(buffer));
// Console.WriteLine(sb.ToString());
sw.WriteLine(sb.ToString());
// sb = new StringBuilder();
return sb;
}
catch (Exception ex)
{
throw new ApplicationException(ex.Message);
}
}
You said you do not want to use an IMAP library. This means that you will have to implement your own. You should start by reading RFC 3501 because there is no chance you could get the protocol right without reading the docs carefuly. In particular, you're issuing a STATUS command on the currently selected mailbox, which is explicitly forbidden by the protocol specification. The rest of the code supports the assumption that you have not read the RFC yet.
How can I get the all HTTP request headers, method, the suffix of the connection, and all parameters that I added to the request?
Try something like this (I ran this code on a background thread, which I why I use UiApplication.invokeLater() to display results):
try {
ConnectionFactory factory = new ConnectionFactory(); // for OS 5.0+
factory.setPreferredTransportTypes(new int[] {
TransportInfo.TRANSPORT_TCP_WIFI,
TransportInfo.TRANSPORT_TCP_CELLULAR
});
// For OS < 5.0
//HttpConnection conn = (HttpConnection) Connector.open("http://www.google.com;interface=wifi");
HttpConnection conn = (HttpConnection) factory.getConnection("http://www.google.com").getConnection();
conn.setRequestProperty("sessionId", "ABCDEF0123456789");
final StringBuffer results = new StringBuffer();
String key = "";
int index = 0;
// loop over all the header fields, and record their values
while (key != null) {
key = conn.getHeaderFieldKey(index);
if (key != null) {
String value = conn.getHeaderField(key);
results.append(key + " = " + value + "\n\n");
}
index++;
}
results.append("method = " + conn.getRequestMethod() + "\n\n");
// we (should) know which request properties we've set, so we ask
// for them by name here
String sessionId = conn.getRequestProperty("sessionId");
results.append("sessionId = " + sessionId + "\n\n");
String url = conn.getURL();
results.append("URL = " + url);
// show the result on screen (UI thread)
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
textField.setText(results.toString());
}
});
} catch (IOException e) {
e.printStackTrace();
}
I created a Tcp Client & Tcp Server in Groovy awhile back and had no issues with it. I was only connecting to one machine at the time to gather data. This time I am attempting to connect to the script on multiple hosts and it is only saving one of the hosts information in my grails app.
My Grails application is simple, it has a domain class for Machines (basically the computers and the information on them that I seek) and it will use my TcpClient.groovy script to connect and gather information from the TcpServer.groovy on the other computers. For each host, it should save the information gathered, however, it seems to skip right over saving any host aside from the last one.
Tcp Client :
//TCP CLIENT
public void queryData(def hosts) {
for(int aHost = 0; aHost < hosts.size; aHost++) {
cristalClient(hosts[aHost]);
}
}
public void cristalClient(String host) {
commands = ["dateScan", "computerName", "ip", "quit"]
answers = [commands.size]
requestSocket = new Socket(host, 2000)
r = new BufferedReader(new InputStreamReader(requestSocket.getInputStream()));
w = new BufferedWriter(new OutputStreamWriter(requestSocket.getOutputStream()));
String message = "Connection was successful"
message = readAvailable(r)
println("Sever>" + message)
for(int n = 0; n < commands.size; n++) {
sendMessage(commands[n]);
answers[n] = readAvailable(r)
}
lastRead = answers[0]
machineName = answers[1]
ipAddress = answers[3]
w.flush()
w.close()
}
public String readAvailable(r) {
String out = ""
String dum = null
while((dum = r.readLine()) !=null) {
if(dum == ">>EOF<<") return out
if(out.length() > 0) out += "\r\n"
out += dum
}
return out
}
public void sendMessage(msg) {
w.write(msg+"\r\n");
w.flush();
println("Client>" + msg);
}
public void printData(abc) {
abc.eachWithIndex { it, index ->
println "Drive $index"
it.each { k, v ->
println "\t$k = $v"
}
}
}
Tcp Server :
//TCP Server
def server = new ServerSocket(2000)
println("Waiting for connection")
server.accept() { socket ->
socket.withStreams { input, output ->
w = new BufferedWriter(new OutputStreamWriter(output))
String message = "Connection was successful"
r = new BufferedReader(new InputStreamReader(input))
while(true) {
if(message != null) {
sendMessage(message)
message = null
}
String a = r.readLine()
if(a == "dateScan") {
message = new Date
} else if(a == "computerName") {
message = InetAddress.getLocalHost().hostName
} else if(a == "ip") {
message = InetAddress.getLocalHost().getHostAddress()
} else if(a == "quit") {
server.close()
return
} else {
message = "$a command unknown."
println message
}
}
}
}
def sendMessage(String msg) {
println( "sending: >" + msg + "<" )
w.writeLine(msg)
w.writeLine(">>EOF<<")
w.flush();
}
Grails Controller :
//Grails Controller
CollectMachines {
def w = new tcpClient()
def hosts = ["winXp", "Win7"]
w.queryData(hosts)
def abc = w.hardDrive
abc.each { println it }
int numberOfDrives = abc.size()
//add new machine
numberOfDrives.times {
def machineName = abc.computerName[it]
def machineInstance = Machine.findByMachineName(machineName)
if (!machineInstance) {
machineInstance = new Machine(machineName)
}
def lastScan = abc.lastScan[it]
def scanDate = new Date().parse("E MMM dd H:m:s z yyyy", lastScan)
def ipAddress = abc.ipAddress[it]
machineInstance.setIpAddress(ipAddress)
machineInstance.setDateScanned(scanDate)
machineInstance.save()
}
redirect(action: "list")
}
Do I need to put a pause in so that the server has time to send a response? My Tcp Client does send out all the commands but only gets responses for the last set of commands.
Also, sorry for the indentation issues with my code snippets, I'm not sure why they are messed up.
.
There are a few problems with your code. tcpClient never assigns to hardDrive, for example. Assuming this is an oversight, I think the real problem is that tcpClient is querying data for multiple hosts, and storing all the results in the same instance variables answers, and ultimately lastRead, machineName, and ipAddress.
You need to store the results for each host separately. One way would be to have answers be a map of lists. For example, answers[host][0] would be the first answer for a given host.
I don't think any kind of pause is necessary.