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Client crashing when running command with Renci SshNet

Currently, when I press the button, it is supposed to restart one of our servers and upon completion return the result. The command runs successfully but after running it, the client crashes because technically the command never really finishes.
After running the command, the server starts running and it will keep outputting server information in the console about the server. How would i make it so that it stops by default after like 15 seconds, or when the output stream is returning emptiness.
I am new to C# so not sure how to approach this.
private void button1_Click(object sender, EventArgs e)
{
using (var client = new SshClient("IP", "USER", "PASS"))
{
label1.Text = "Status: Initiated restart";
client.Connect();
var cmd = client.RunCommand("./server restart && ./server2 restart");
var result = cmd.Execute();
client.Disconnect();
label1.Text = "Status: Restart completed";
}
}
This is my code. Normally, if you type a command (like LS) it will return the output, then let your type again. But in this case, the server keeps running so it will not let you type anything again, thus its not recognized as the command has finished, as it is still running.

I'm not quite sure if I get you right, but I would wrap try and catch around the problematic code, especially if you don't care about the output in that case.
private void button1_Click(object sender, EventArgs e)
{
using (var client = new SshClient("IP", "USER", "PASS"))
{
label1.Text = "Status: Initiated restart";
try
{
client.Connect();
var cmd = client.RunCommand("./server restart && ./server2 restart");
var result = cmd.Execute();
client.Disconnect();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
label1.Text = "Status: Restart completed";
}
}

Progressbar on Waitform freezes using a Task run on another Thread

I have an application which gets data from Excel Sheets using OleDb.
On the Form I have controls so the user can filter the data to his needs.
For example, FileSize, UserID, Rootpath etc. This works perfectly.
After final selection the User has to press an "update" Button so I can filter the data based on his input. The result will be shown in a DataGridView.
However, since the Data on the Excel Sheets varies a lot, I used to have a ProgressBar on a second Form (Waitform) or make the DataGridView invisible while the ProgressBar on the UI is visible during the non-UI-Task (Data Collection).
I do know that I should use a Task or a Thread (or a BackGroundWorker) to keep the UI responsive.
That being said, it still freezes my whole application.
//Update Button which uses all the userdefined filters
private async void updateButton_Click(object sender, EventArgs e)
{
WaitBarDatagrid.Visible = true; //Progressbar is called WaitBarDatagrid
WaitBarDatagrid.Style = ProgressBarStyle.Marquee;
WaitBarDatagrid.MarqueeAnimationSpeed = 30;
dataGridView1.Visible = false;
await Task.Run(() => QueryToExcel());
dataGridView1.DataSource = FileInfos;
WaitBarDatagrid.Visible = false;
dataGridView1.Visible = true;
}
private void QueryToExcel()
{
this.Invoke((MethodInvoker)delegate ()
{
string fSize;
if (FileSizeComboBox.Text == "All Data")
{ fSize = "0"; }
else if (FileSizeComboBox.Text == "> 1 MB")
{ fSize = "1000"; } // 1MB = 1000kB
else if (FileSizeComboBox.Text == "> 10 MB")
{ fSize = "10000"; } // 10MB = 10.000kB
else if (FileSizeComboBox.Text == "> 100 MB")
{ fSize = "100000"; } // 100MB = 100.000kB
else if (FileSizeComboBox.Text == "> 1 GB")
{ fSize = "1000000"; } // 1 GB = 1000.000 kB
else
fSize = "0";
// The following ensures that all possibilities of User Definition are covered
string user = "";
string size = "";
string sep = ""; //Seperator
if (!string.IsNullOrEmpty(UserTextbox.Text))
{
user = $"[UserID] = '{UserTextbox.Text}'";
sep = "AND";
}
if (!string.IsNullOrEmpty(FileSizeComboBox.Text))
{
size = $"{sep} [File Size] >= {fSize}";
sep = "AND";
}
//Final Where CLAUSE based on User Input
//string command = $#"{user} {size}{sep} [Date] <= {DateBox.Value.ToOADate()}";
string command = $#"{user} {size} {sep} [Date] <= {DateBox.Value.ToOADate()}";
//Call Data from Excel
string connectionString = GetConnectionString(Datapath + RootCombobox.Text);
string query = $#"SELECT * from [FileInfos$] WHERE ({command})";
DataTable dt = new DataTable();
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
conn.Open();
using (OleDbDataAdapter dataAdapter = new OleDbDataAdapter(query, conn))
{
try
{
dataAdapter.Fill(dt);
FileInfos = dt;
}
catch (System.Data.OleDb.OleDbException ex)
{
MessageBox.Show(ex.ToString());
}
}
}
});
}
So far I also have tried to assign the values of the Userinputs to global variables and it will be changed in their correspondent events. However, even with invoke my UI freezes. Where does it come from?

The QueryToExcel() method is supposed to queue the work to run on a ThreadPool Thread, to let UI Thread continue its own work without freezing.
But you notice that the UI freezes anyway, saying:
even with invoke my UI freezes
It's invoking the UI thread from another thread that freezes it.
Doing work on another thread is about not using the UI thread. If we invoke back the UI thread from a worker thread, the effect is lost (or partially lost, annoying in any case).
You're also using Invoke() instead of BeginInvoke(). The latter is executed asynchronously: it returns immediately and can prevent deadlocks if the control invoked is busy or otherwise unreachable/unresponsive.
It won't prevent the UI from stuttering at times, anyway.
Looking at the code you presented here, it appears that there's no need to invoke the UI thread at all: the secondary thread just needs the properties values of some controls and then assigns a DataTable to a field.
It is then possible to pass to this method the required values as arguments, assigning the Controls' properties to some variables or to the properties of a class (so it's easier to understand what the arguments contain).
the worker method could be changed in
private DataTable QueryToExcel(string[] paramArray)
Or
private DataTable QueryToExcel(SomeClass values)
and can be called as:
private async void updateButton_Click(object sender, EventArgs e)
{
var dt = await Task.Run(() => QueryToExcel(values));
Or
dataGridView1.DataSource = await Task.Run(() => QueryToExcel(values));
}
In QueryToExcel() to Excel:
Access the values parameter to setup the query or other processing.
Create the DB Connection and fill a DataTable/DataSet.
Dispose of all the disposable objects created (Connection/DataAdapter etc)
Return a DataTable

Your code basically jumps to a non-UI thread and then jumps back to the UI - it's almost as if you never left the UI thread.
What you need to do is do all of your UI work on the UI thread and only do non-UI work on the other thread.
Try this code:
// Define other methods and classes here
//Update Button which uses all the userdefined filters
private async void updateButton_Click(object sender, EventArgs e)
{
WaitBarDatagrid.Visible = true; //Progressbar is called WaitBarDatagrid
// WaitBarDatagrid.Style = ProgressBarStyle.Marquee;
// WaitBarDatagrid.MarqueeAnimationSpeed = 30;
dataGridView1.Visible = false;
string fSize;
if (FileSizeComboBox.Text == "All Data")
{ fSize = "0"; }
else if (FileSizeComboBox.Text == "> 1 MB")
{ fSize = "1000"; } // 1MB = 1000kB
else if (FileSizeComboBox.Text == "> 10 MB")
{ fSize = "10000"; } // 10MB = 10.000kB
else if (FileSizeComboBox.Text == "> 100 MB")
{ fSize = "100000"; } // 100MB = 100.000kB
else if (FileSizeComboBox.Text == "> 1 GB")
{ fSize = "1000000"; } // 1 GB = 1000.000 kB
else
fSize = "0";
// The following ensures that all possibilities of User Definition are covered
string user = "";
string size = "";
string sep = ""; //Seperator
if (!string.IsNullOrEmpty(UserTextbox.Text))
{
user = $"[UserID] = '{UserTextbox.Text}'";
sep = "AND";
}
if (!string.IsNullOrEmpty(FileSizeComboBox.Text))
{
size = $"{sep} [File Size] >= {fSize}";
sep = "AND";
}
//Final Where CLAUSE based on User Input
//string command = $#"{user} {size}{sep} [Date] <= {DateBox.Value.ToOADate()}";
string command = $#"{user} {size} {sep} [Date] <= {DateBox.Value.ToOADate()}";
await Task.Run(() => QueryToExcel(command, RootCombobox.Text));
dataGridView1.DataSource = FileInfos;
WaitBarDatagrid.Visible = false;
dataGridView1.Visible = true;
}
private void QueryToExcel(string command, string RootCombobox_Text)
{
//Call Data from Excel
string connectionString = GetConnectionString(Datapath + RootCombobox_Text);
string query = $#"SELECT * from [FileInfos$] WHERE ({command})";
DataTable dt = new DataTable();
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
conn.Open();
using (OleDbDataAdapter dataAdapter = new OleDbDataAdapter(query, conn))
{
try
{
dataAdapter.Fill(dt);
this.Invoke((MethodInvoker)delegate () { FileInfos = dt; });
}
catch (System.Data.OleDb.OleDbException ex)
{
this.Invoke((MethodInvoker)delegate () { MessageBox.Show(ex.ToString()); });
}
}
}
}
It's untested, but it should be close. Note that non of the UI elements are accessed or updated on any non-UI thread.

Delay to SQL Server throw an exception

I have this Code to Get a table Data From SQL Server:
public static System.Data.Linq.Table<Equipment> GetEquipmentTable()
{
DataClassesDataContext dc = new DataClassesDataContext();
return dc.GetTable<Equipment>();
}
I Have a Button to call this Function :
private void button_Click(object sender, RoutedEventArgs e)
{
MyListView.DataContext = GetEquipmentTable();
}
My Problem is :When I Disable Communication Between my App and SQL Server Machine and then click this button, It takes a while to throw an Exception that Connect to Database is impossible!!!! My major problem is that my app freezed till this Exception accrued.
Did I missed something ?
Update 1 :
I used async and wait base on Rahul solution
public static async Task<System.Data.Linq.Table<Equipment>> GetEquipmentTable()
{
DataClassesDataContext dc = new DataClassesDataContext();
return dc.GetTable<Equipment>();
}
private async void button_Click(object sender, RoutedEventArgs e)
{
MyListView.DataContext = await GetEquipmentTable();
}
but it still wait for this line of code :
return dc.GetTable<Equipment>();
and UI freezes as well.
I think dc.gettable<> is not waitable or somthing else !!??

When I Disable Communication Between my App and SQL Server Machine and
then click this button
That's obvious right since it tries to connect to the machine (within the Timeout mentioned in connection string) and then throws the exception back once it finds that the server isn't reachable.
major problem is that my app freezed till this Exception accrued
Probably in that case make the method as async method like
public static async Task<System.Data.Linq.Table<Equipment>> GetEquipmentTable()
{
DataClassesDataContext dc = new DataClassesDataContext();
return dc.GetTable<Equipment>();
}
Your event handler
private async void button_Click(object sender, RoutedEventArgs e)
{
MyListView.DataContext = await GetEquipmentTable();
}

You have two problems, the app freezing is because you are not using asynchronous programming.
The delay before the connection exception is because the client side app waits until the connection timeout timer finishes (30 seconds default).
Try using async await on your database calls to free up the UI.
Try changing the connection timeout to 5 seconds in the connection string.
Change in connection string:
"Data Source=...;Connect Timeout=5"

Use await as in the answer from Rahul. +1
You could also test a simple SqlConnection.Open
private static bool OpenSqlConnection(string connectionString)
{
bool return = false;
try
{
SqlConnection connection = new SqlConnection(connectionString);
connection.Open();
return = true;
}
catch (Exception ex)
{
return = false;
}
finally
{
connection.Close();
}
return return;
}
Could use SqlConnection.OpenAsync.
SqlConnection con = new SqlConnection("connection string");
bool resp = false;
try
{
con.OpenAsync();
resp = true;
}
catch (SqlException ex)
{
//use the ex message
resp = false;
}
catch (Exception ex)
{
resp = false;
}
finally
{
con.Close();
}

how to make progress bar work with functions in button event

i am new in C# so please be patient with me .
i want to make progress bar work with any functions i make in my program
i have class to check if INTERNET available and the connection of database status
and i have "progressBar1" , style is "Marquee"
i just want to indicate that there is a process work "Function" in the program and i don't need to have step or timer to increment it
just make the progress work until the function finish its code and the functions will work in button event (when i push button)
this is my code
class checkInternet
{
[DllImport("wininet.dll")]
private extern static bool InternetGetConnectedState(out int Description, int ReservedValue);
public bool checkInternetAvailable()
{
int Desc;
bool result = false;
if (InternetGetConnectedState(out Desc, 0) == true)
{
try
{
dbConnection StartConn = new dbConnection();
SqlConnection MyConnetion = StartConn.GetConnection();
MyConnetion.Open();
if (MyConnetion.State == ConnectionState.Open)
{
result = true;
}
MyConnetion.Close();
}
catch (Exception)
{
result = false;
MessageBox.Show("The database connection does not available, May be because of this reasons: \n\n1- there is a new version of the program avalible. \n2- database has some maintenance. \n\n Please check later :)", "Conection status");
}
}
else
{
result = false;
MessageBox.Show("No internet connection avalible , Please check later :) \nThanks.", "Conection status");
}
return result;
}
}
and this is what i have in my button event
private void button1_Click(object sender, EventArgs e)
{
checkInternet check = new checkInternet();
progressBar1.Value = 0;
do
{
progressBar1.PerformStep();
} while (check.checkInternetAvailable());
}
how can i implement that ?
thanks

As I understand you want user to see progressbar while your check connection task executes in background. checkInternetAvailable would be your background operation and I wouldn't suggest showing messages directly form it. Instead return a custom struct :
public struct ConnectionCheckResult
{
public bool Success;
public string Message;
}
And this will be your button click event handler :
private void button1_Click(object sender, EventArgs e)
{
progressBar1.Style = ProgressBarStyle.Marquee;
progressBar1.Visible = true;
//add code here to be executed on UI thread before connection check
Task.Run(new Action(() =>
{
//Task.Run this code on the thread pool instead of your UI thread. So your code is checking connection while progress bar is still rendering
ConnectionCheckResult res = new checkInternet().checkInternetAvailable();
this.Invoke(new Action(() =>
{
//this.Invoke executes following delegate on UI thread. All UI changes - like progressBar1.Visible = false; need to be made in UI thread.
//add code here to be executed on the UI thread after connection check.
progressBar1.Visible = false;
if (!string.IsNullOrEmpty(res.Message))
MessageBox.Show(res.Message);
}));
}));
//add code to be executed on UI thread at the same time as connection check
}
I know multi-threading is difficult to wrap your head around at first, here's good tutorial with code samples.
Also when your progressbar style is Marquee you don't need to call PerformStep. It will just roll by itself.
EDIT: You should also modify checkInternetAvailable() like so :
public ConnectionCheckResult checkInternetAvailable()
{
int Desc;
ConnectionCheckResult result = new ConnectionCheckResult();
if (InternetGetConnectedState(out Desc, 0) == true)
{
try
{
dbConnection StartConn = new dbConnection();
SqlConnection MyConnetion = StartConn.GetConnection();
MyConnetion.Open();
if (MyConnetion.State == ConnectionState.Open)
{
result.Success = true;
}
MyConnetion.Close();
}
catch (Exception)
{
result.Success = false;
result.Message = "The database connection does not available, May be because of this reasons: \n\n1- there is a new version of the program available. \n2- database has some maintenance. \n\n Please check later :)";
}
}
else
{
result.Success = false;
result.Message = "No internet connection available , Please check later :) \nThanks.";
}
return result;
}

How to Deal with Asynchronous SQL Queries from Non-UI Threads

All, I have successfully used ADO.NET to make use of asynchronous SQL queries similar to the example below. In the example shown the method ExecNonQuery is being invoked from the UI thread. This works well, but I wondered how I would handle the callback if I were to call ExecNonQuery from a non-UI thread?
Note. Clearly, in such a case I would amend ExecNonQuery, so that such things as this.toolStripStatusLabel1.Text were dealt with accordingly, or removed.
public bool ExecNonQuery(string strCmd, string strUserMsg = "")
{
try
{
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = strCmd;
cmd.CommandTimeout = 0;
bIsExecuting = true;
AsyncCallback callback = new AsyncCallback(HandleCallback);
cmd.BeginExecuteNonQuery(callback, cmd);
return true;
}
catch (Exception Ex)
{
bIsExecuting = false;
this.toolStripStatusLabel1.Text = String.Format("Ready (last error: {0})", Ex.Message);
if (conn != null)
conn.Close();
}
return false;
}
private delegate void DisplayInfoDelegate(string Text);
private void HandleCallback(IAsyncResult result)
{
try
{
// Retrieve the original command object, passed
// to this procedure in the AsyncState property
// of the IAsyncResult parameter.
SqlCommand command = (SqlCommand)result.AsyncState;
int rowCount = command.EndExecuteNonQuery(result);
string rowText = " rows affected.";
if (rowCount == 1)
rowText = " row affected.";
rowText = rowCount + rowText;
// Call the procedure from the form's thread.
DisplayInfoDelegate del = new DisplayInfoDelegate(DisplayResults);
this.Invoke(del, rowText);
}
catch (Exception ex)
{
// Because you are now running code in a separate thread,
// if you do not handle the exception here, none of your other
// code catches the exception.
// You can create the delegate instance as you
// invoke it, like this:
this.Invoke(new DisplayInfoDelegate(DisplayResults),
String.Format("Ready(last error: {0}", ex.Message));
}
finally
{
bIsExecuting = false;
if (conn != null)
conn.Close();
}
}
private void DisplayResults(string Text)
{
this.toolStripStatusLabel1.Text = Text;
this.toolStripProgressBar1.Style = ProgressBarStyle.Blocks;
this.toolStripProgressBar1.Value = 100;
}
Thanks for you time.

It makes no difference to your callback which thread runs ExecNonQuery - HandleCallback will still be run on a thread pool thread.
You have already spotted the change you need to make: don't access UI controls directly in ExecNonQuery if it is not being run on the UI thread.
Nick