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Hey Folks
I'm writing a little telnet client, after a few days
i had it working for receiving, but it refuses to send.
Someone has a idea what is going wrong or what i'm overlooking?
here are 2 send parts one normal and one asynchrone
Normal:
array<Byte>^ SendMessage = Encoding::ASCII->GetBytes("DATA TO SEND");
Sock->Send(SendMessage, SendMessage->Length, SocketFlags::None);
Asynchrone:
public: void SendMessage(String^ UserMessage)
{
if (Sock == null || Sock->Connected == false)
{
text_output->Text += "\nERROR: First connect before sending data.\n";
return;
}
try
{
array<Byte>^ SendMessage = Encoding::ASCII->GetBytes("DATA TO SEND");
Sock->BeginSend(SendMessage, 0, SendMessage->Length, SocketFlags::None, gcnew AsyncCallback(this, namesp_class::SendData), Sock);
}
catch (...)
{
text_output->Text += "ERROR: Could not send message.\n";
}
}
public: void SendData (IAsyncResult^ ar)
{
Socket^ s = (Socket^)ar->AsyncState;
int send = s->EndSend(ar);
}
If anyone is interested here's the rest
Socket^ Sock;
array<Byte>^ InputBuffer;
public: void Telnet_Load()
{
Delegate_AddMessage = gcnew AddMessage (this, namesp_class::OutputMessage);
this->output_textbox->TextChanged += gcnew System::EventHandler(this, namesp_class::output_textbox_TextChanged);
}
public: void Read(String^ Host, int Port)
{
Cursor = Cursors::WaitCursor;
try
{
if (Sock != null && Sock->Connected == true)
{
Sock->Shutdown(SocketShutdown::Both);
sleep(10);
Sock->Close();
}
Sock = gcnew Socket(AddressFamily::InterNetwork, SocketType::Stream, ProtocolType::Tcp);
IPEndPoint^ ip = gcnew IPEndPoint (IPAddress::Parse(Host), Port);
Sock->Blocking = false;
AsyncCallback^ onconnect = gcnew AsyncCallback(this, namesp_class::OnConnect);
Sock->BeginConnect(ip, onconnect, Sock);
}
catch (...)
{
Invoke (Delegate_AddMessage, "ERROR: Could not connect to remote machine.\n");
}
Cursor = Cursors::Arrow;
}
public: void OnConnect(IAsyncResult^ ar)
{
Socket^ s = (Socket^)ar->AsyncState;
try
{
if (s->Connected == true)
{
Invoke (Delegate_AddMessage, "Connected.\n");
SetupReceiveCallback(s);
}
else
{
Invoke (Delegate_AddMessage, "ERROR: Could not connect to remote machine.\n");
}
}
catch (...)
{
Invoke (Delegate_AddMessage, "ERROR: Unknow error during connect.\n");
}
}
public: void SetupReceiveCallback(Socket^ s)
{
InputBuffer = gcnew array<Byte>(InputBufferSize);
try
{
AsyncCallback^ Receive = gcnew AsyncCallback(this, namesp_class::OnReceivedData);
s->BeginReceive(InputBuffer, 0, InputBuffer->Length, SocketFlags::None, Receive, s);
}
catch(...)
{
Invoke (Delegate_AddMessage, "ERROR: Setup receive callback failed.\n");
}
}
public: void OnReceivedData(IAsyncResult^ ar)
{
Socket^ s = (Socket^)ar->AsyncState;
try
{
int bytes = s->EndReceive(ar);
if (bytes > 0)
{
String^ receivedmessage = Encoding::ASCII->GetString(InputBuffer, 0, bytes);
receivedmessage = "> " + receivedmessage + "\n";
array<Object^>^ stringarray = {receivedmessage};
Invoke (Delegate_AddMessage, stringarray);
SetupReceiveCallback(s);
}
}
catch (...)
{
Invoke (Delegate_AddMessage, "ERROR: error during data receive.\n");
}
}
public: void CloseConnection()
{
if (Sock != null && Sock->Connected == true)
{
Sock->Shutdown(SocketShutdown::Both);
sleep(10);
Sock->Close();
}
}
public: void OutputMessage (String^ Message)
{
String^ FirstChar = Message[0].ToString();
if (FirstChar == ">")
{
output_textbox->SelectionColor = Received_Message_Color;
output_textbox->SelectedText += Message;
}
else
{
output_textbox->SelectionColor = Program_Message_Color;
output_textbox->SelectedText += Message;
}
}
public: void output_textbox_TextChanged(System::Object^ sender, System::EventArgs^ e)
{
output_textbox->Focus();
output_textbox->SelectionLength = 0;
output_textbox->SelectionStart = output_textbox->TextLength;
output_textbox->ScrollToCaret();
}
modified on Sunday, August 29, 2010 10:29 AM
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the synchronous one seems almost correct, as the doc[^] says:
public int Send(
byte[] buffer,
int size,
SocketFlags socketFlags
)
Are you sure the async one fails?
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Hey Luc
I'm sorry i see the mistake in the code, i deleted the code when i wrote the async
but for here put the sync one back to show what i tried but made the mistake.
when i put:
Sock->Send(SendMessage, SendMessage->Length, SocketFlags::None);
Like it was then it still won't work.
i send the data but get no reply from the server.
i put the source in a rar it's on http://www.rikterveen.nl/Telnet.rar
modified on Wednesday, September 1, 2010 8:05 AM
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We have an activex control where C++/CLI components interact with WPF controls; instance of WPF controls wrapped in gcroot<> in the C++/CLI components. Problem started when we hosted the activex control in IE, where calls starting from unmanaged zone always get into the default appdomain whereas WPF controls get created in the the 'localhost' or 'web page' specific appdomain. I want to know if there is a possibility to get the unmanaged calls start from the 'web page' appdomain.
Thanks & Regards
Venkatesh
modified on Friday, August 27, 2010 7:21 AM
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Hi everyone, I am having some deficulty delete dataGridView rows From My DataGridView.
I tried following:
for(int j =0;j<this->s_dataGridView->Rows->Count;j++)
{
this->s_dataGridView->Rows->RemoveAt(j);
}
and
int j = this->s_dataGridView->RowCount;
while(j<=0)
{
this->s_dataGridView->Rows->RemoveAt(j);
rowCount --;
}
it seems like not working.
Yes I found My own Solution
this is how it works when the entire row collection is needed to delete;
for each (System::Windows::Forms::DataGridViewRow^ row in this->securityCodedataGridView->Rows)
{
this->securityCodedataGridView->Rows->Remove(row);
}
modified on Monday, August 23, 2010 11:28 AM
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Explanation:
for(int j =0;j<this->s_dataGridView->Rows->Count;j++)
{
this->s_dataGridView->Rows->RemoveAt(j);
}
for(int j =0;j<this->s_dataGridView->Rows->Count-1;j++)
{
this->s_dataGridView->Rows->RemoveAt(j);
}
and again
int j = this->s_dataGridView->RowCount;
while(j<=0)
{
this->s_dataGridView->Rows->RemoveAt(j);
rowCount --;
}
int j = this->s_dataGridView->RowCount-1;
while(j>=0)
{
this->s_dataGridView->Rows->RemoveAt(j);
j--;
}
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Hi barbetto80, Thanks so much for your help. Sometimes little mistake can go very wrong.
Now it is working.
thanks again
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the logical approach:
while(RowCount!=0) Rows.RemoveAt(0);
the smart approach:
Rows.Clear();
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I am talking to a MS Access database using C++/CLI. All is well untill I try to retrieve Date data: When the day is single digit, it refuses to see it (but doesn't throw an error) . My query goes:
String^ query = "SELECT * FROM MyTable WHERE (aNumberField = " + aValue +
"AND aDateField = #" + aDate + "#) ORDER BY aNumberField";
'aDate' in the above is a string in the format dd/mm/yyyy
This format is also enforced in the Date field of the MS Access database.
I also physically add a zero at the start of any one digit day field, so the string looks like "05/12/2010" instead of "5/12/2010". But that doesn't help. Remember that the above works fine with 2-digit day fields, i.e. a date like "15/12/2010" works fine.
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I would never do it that way. Unless you have set some CultureInfo stuff for the thread, it will use an implicit ToString() that applies the datetime formatting rules your user has set out through "Regional Settings". However user-defined settings should apply to the GUI only, not to formatting in files or databases.
You really should fix the datetime formatting by explicit code, so I recommend something along these lines:
String^ query = "... #" + aDate.ToString("dd/MM/yyyy") + "#...";
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Thanks Luc. Yes, I tried many solutions along that line, such as:
System::DateTime^ tUpdated = DateTime::Parse(myDateString, System::Globalization::CultureInfo::CreateSpecificCulture("en-AU")->DateTimeFormat);
String^ thisString = String::Concat("#",tUpdated->ToShortDateString(),"#");
When debugging, the resulting string shows properly formatted. I'm starting to think maybe I need to rebuild the Access Database.
modified on Monday, August 23, 2010 10:34 PM
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Dirkus Maximus wrote: tUpdated->ToShortDateString
That does not make any sense. ToLongDate() and ToShortDate() adhere to your user's preferences, hence are not the right tool for database operations.
I am not familiar with a "MS Access Short Date" type, I only know of "date/time" type, which matches perfectly with a DateTime in my experience. Here is a bit of C# code I have used a lot; one could do the same things in C++/CLI:
public static DateTime GetDateTime(DataRow row, string fieldName) {
object field=row[fieldName];
if (field is DBNull) return DateTime.MinValue;
return (DateTime)field;
}
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Thanks again Luc, that is good information. But I understand that, in the end, you can only query a database using a text string. I can narrow my problem down to the following:
I do a query
"SELECT someDate FROM myTable WHERE someField = 34"
and I get a return from the DB
I confirm, using a GetType(), that it is of type DateTime
I do a 'ToString()' and that returns
06/07/2010 12:00:00 AM
Now I query the Database with
"SELECT * FROM MyTable WHERE someDate = #06/07/2010 12:00:00 AM#"
It doesn't return anything.
While if do another query with a 2-digit day field, such as #16/07/2010 12:00:00 AM#, it works.
*** Update ***
The following work-around worked:
"SELECT someDate FROM myTable WHERE (someDate >= #6/07/2010#) AND (someDate <= #7/07/2010#)"
Any suggestions why this works and the previous one didn't?
modified on Tuesday, August 24, 2010 3:56 AM
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The proper way to handle dates and times would be to use SqlParameter, unfortunately that does not work for Access, so yes you need to convert DateTime values to string literals.
Dirkus Maximus wrote: I do a 'ToString()' and that returns 06/07/2010 12:00:00 AM
You seem to still not understand the concept of regional settings; ToString() shows the data formatted like the user (you) said he wanted it, see the Control Panel ("Regional Settings" or "Dates and Times"); it is unrelated to the format your database requires.
I found some more C# code that should be useful:
public static string Date(DateTime date) {
return date.ToString("#yyyy-MM-dd#");
}
Do you see how it enforces a format independent of the user's Control Panel settings? (and different from what you think it should be).
And I use it like this:
string query="... WHERE myDateField = "+Date(myDateTime)+"...";
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Hi Luc
Luc Pattyn wrote: ToString() shows the data formatted like the user (you) said he wanted it, see the Control Panel ("Regional Settings" or "Dates and Times")
Now I got you (little did I know).
Turned out I forgot that MS Access uses the JET engine. That's what happens when you leave a gap between researching what database to use and the actual implementation. At http://technet.microsoft.com/en-us/library/cc966377.aspx, I found the following:
Note that this date literal must always be expressed in MM/DD/YY order. To avoid the ambiguity of the meaning of stored queries, Microsoft Jet doesn't follow the international date format settings specified in the user's Control Panel.
So, given my example given earlier, all I needed to do was:
"SELECT * FROM MyTable WHERE someDate = #7/6/10#"
As I understand now, it would be better to work with DateTime types in the implementation, and convert them to properly formatted Strings in queries. Anyway, many thanks for all your effort.
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Dirkus Maximus wrote: Microsoft Jet doesn't follow the international date format settings specified in the user's Control Panel.
That is correct, it holds true for each and every database; databases don't care about human users and their formatting preferences. After all, their data needs to be portable across the world.
Dirkus Maximus wrote: Note that this date literal must always be expressed in MM/DD/YY order.
That is a surprise to me. I have always used yyyy-MM-dd and that has served me well, probably because it is unambiguous and easy to understand, so I suspect the MSDN statement is overly strict, in real life JET seems to accept more than one format.
What remains is your now puzzling statement a date like "15/12/2010" works fine at the end of your very first message in this thread. It clearly follows dd/MM/yyyy which is yet another format, and yet you said it worked well. I don't have an official reference, however some pages (such as this[^] one) claim JET is quite forgiving, but when in doubt looks for m/d/y.
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Hi Dirkus,
I now have expanded a pre-existing article [^]of mine on DateTime, by adding the essentials of what we discussed today. Maybe it is of further interest to you.
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Great article Luc - very informative. I ended up having a DateTime representation of the Date instead of just a String.
DateTime^ dt = gcnew DateTime(yearField, monthField, dayField);
And when I need to insert it in the DB, I use the format you advocate:
String^ query = "INSERT INTO myTable (..., someDateField, ...) Values(..., dt->ToString("yyyy'/'MM'/'dd"), ..."
To retrieve it back, I use what the JET documentation says, i.e. I convert it into the MM/DD/YY form first.
array <String^>^ strArr = fromDate->Split('/');
int dayField = Convert::ToInt32(strArr[0]);
int monthField = Convert::ToInt32(strArr[1]);
String^ yearField = Convert::ToString(strArr[2]);
yearField = yearField->Substring(2,2);
String^ formattedDate = String::Concat(" #",Convert::ToString(monthField),"/", Convert::ToString(dayField),"/", yearField,"# ");
query = "SELECT * FROM myTable WHERE someDate = " + formattedDate + ";
It's all a bit convoluted, but this method is working well now.
I don't know why (as described in my first post) this 'one digit' day didn't work while the '2-digit' one did - though I did forget to mention that I'm using quite an early version of MS Access (2003), so this problem may be fixed by now.
Just one other thing, from an MSDN forum I learned that
JET SQL supports different types. You can declare parameter type by using PARAMETERS clause. The OleDB provider in ADO.Net does not support named parameters.
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Dirkus Maximus wrote: Great article Luc - very informative
Thanks.
Dirkus Maximus wrote: It's all a bit convoluted
Yes it is. I don't understand why you would do inserts and selects differently. The simple
dt->ToString("yyyy'/'MM'/'dd") or dt->ToString("yyyy-MM-dd") should work here too. And you could incorporate the # signs in the format string.
Dirkus Maximus wrote: I don't know why (as described in my first post) this 'one digit' day didn't work while the '2-digit' one did
I have strong doubts your 2-digit dates did work correctly all the time. The way I see it, Access (or ADO.NET) tries to interpret your date literals as mm/dd/yy unless they are clearly something else (as with my yyyy-mm-dd). However as soon as the first number exceeds 12, they understand it can't be mm/dd/yy, so they look for dd/mm/yy and IMO that is why it seemed to work, but not for 1-digit days.
Dirkus Maximus wrote: JET SQL supports different types. You can declare parameter type by using PARAMETERS clause. The OleDB provider in ADO.Net does not support named parameters.
AFAICR I've never seen anyone do Access without OLEDB.
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Luc Pattyn wrote: I don't understand why you would do inserts and selects differently
Yes, I made things much too difficult. There's no need for splitting strings and all that.
When I get a DataType back from the database and need to display it in text, I just go
String^ text = ((DateTime)datarow[4]).ToString("dd MMM yyyy")
And to put a text like the above into a query, I convert it back with
String^ query = "SELECT * FROM myTable WHERE myDate = #" + text + "#)";
Things become embarrasingly clear once you get to see the whole picture
Luc Pattyn wrote: I have strong doubts your 2-digit dates did work correctly all the time
That sounds plausible.
Thanks Luc
modified on Thursday, August 26, 2010 11:05 PM
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Hi,
I am currently working on extending an existing C++ project with new functions. The existing project is made using C++, without using managed variables. I would like to insert some of my function which I have written in C++/CLI, so with managed variables.
Is it possible to declare a managed variable within a class, without making the class a ref class? If I have to make it a ref class it produces a load of errors, as it is connected with parts of existing code that cannot deal with that.
Any ideas would be more than welcome!
Thanks,
Arjen
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Arjen Tjallema wrote: Is it possible to declare a managed variable within a class, without making the class a ref class? If I have to make it a ref class it produces a load of errors, as it is connected with parts of existing code that cannot deal with that.
Any ideas would be more than welcome!
Yes, you can. You need to use a gcroot .
See http://msdn.microsoft.com/en-us/library/481fa11f(VS.80).aspx[^]
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It is possible to recompile native code as managed code. You can build wrapper class to expose unmanaged C++ code in CLI. Then you can use managed infrastructure in your code. Check G. Hogenson "C++/CLI" book.
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Thanks a lot, I'll go find out more about it.
Regards,
Arjen
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hi guys, am having problem with angle rotations..
i already have the formula,
double fangle;
double m_iAngle;
m_iAngle = 45;
POINT centerPt;
centerPt.x = m_nCarX + 161; // which s is the x origin
centerPt.y = y + 52; // which s is the y origin
fangle = m_iAngle / 180. * 3.1415926;
float OrX = (float)(centerPt.x - cos(fangle)*centerPt.x + sin(fangle)*centerPt.y);
float OrY = (float)(centerPt.y - cos(fangle)*centerPt.y - sin(fangle)*centerPt.x);
//tyre spoke
dc.SelectStockObject(GRAY_BRUSH);
dc.SelectObject(m_penTyreSpoke);
for(int count = 0, count < 4, count++){
//spoke1
dc.MoveTo(m_nCarX + 161, y + 52);
dc.LineTo(m_nCarX + 161, y + 41);
}
//see image here:
http://h1.ripway.com/lgmanuel/Imgs/car.png[^]
as you see in the image. the car's tire has only one spoke.
am trying to loop the code to have 4 (four) spokes on my rim by bending the angle 90 DEGREES..
adding a 90 DEGREES on LOOP...
//should look like this images bellow:
http://h1.ripway.com/lgmanuel/Imgs/car-with-rim-spoke.png[^]
help guys.. check the project bellow.. thanks ahead..
http://h1.ripway.com/lgmanuel/VisualCPP/GDICarSample.rar[^]
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