Managed C++/CLI

deterministic cleanup in C++/CLI

3-Jul-07 6:42

This Solution to my problem

// Boolean flag used to determine when a character other than a number is entered.
private:
bool nonNumberEntered;

// Handle the KeyDown event to determine the type of character entered into the control.
void textBox1_KeyDown( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^ e )
{
// Initialize the flag to false.
nonNumberEntered = false;

// Determine whether the keystroke is a number from the top of the keyboard.
if ( e->KeyCode < Keys::D0 || e->KeyCode > Keys::D9 )
{
// Determine whether the keystroke is a number from the keypad.
if ( e->KeyCode < Keys::NumPad0 || e->KeyCode > Keys::NumPad9 )
{
// Determine whether the keystroke is a backspace.
if ( e->KeyCode != Keys::Back )
{
// A non-numerical keystroke was pressed.
// Set the flag to true and evaluate in KeyPress event.
nonNumberEntered = true;
}
}
}
}

// This event occurs after the KeyDown event and can be used to prevent
// characters from entering the control.
void textBox1_KeyPress( Object^ /*sender*/, System::Windows::Forms::KeyPressEventArgs^ e )
{
// Check for the flag being set in the KeyDown event.
if ( nonNumberEntered == true )
{ // Stop the character from being entered into the control since it is non-numerical.
e->Handled = true;
}
}

rockonedge26-Jun-07 21:48

rockonedge

26-Jun-07 21:48

I tried the following code

StreamWriter^ f = gcnew StreamWriter(L"d:\\listfile.txt");<br />
f->Write(L"begin");

expecting a file containing the string "begin" to be created.

To my surprise, only an empty listfile.txt was created. "begin" was not written.
after a few trials, I realized I must explicitly call f->Close() to get "begin" to be written.

is it true that one of the advantages of C++/CLI over c# is that when an object goes out of scope, there is something called deterministic cleanup to close the object, or am I miseducated?

For std::fstream, I surely don't have to call close() explicitly.

Re: deterministic cleanup in C++/CLI

Geo Pa27-Jun-07 3:52

Geo Pa

27-Jun-07 3:52

You can use implicitly dereferenced variables. These variables use the Resource Acquistion Is Initialization (RAII) principle to do their clean up. Also, these variables have the same limiitations as automatic variables:

StreamWriter f(L"D:\\listfile.txt");
f.Write(L"begin");
...
// When "f" goes out of scope, it will be deterministically disposed of.

In order to obtain a tracking handle to an implicitly dereferenced variable, you must prefix it with "%".

byte C# to C++

C#Coudou26-Jun-07 19:22

C#Coudou

26-Jun-07 19:22

Whats wrong with my C++ code, it gets me an error.
How to use byte array in C++ by the way?

C# code:

int data_size = 146000;
int data_loop = 4096;
byte[] data_sent= new byte[data_size];
Random rnd = new Random();
rnd.NextBytes(data_sent);

for (int x = 0; x < data_size; x++)
if (data_sent[x] == 0x3f){
data_sent[x] = 0;
}

C++ code:

int data_size = 146000;
int data_loop = 4096;
Byte[] data_sent = gcnew Byte[data_size]; //Gets me error
Random^ myrandom = gcnew Random;
myrandom->NextBytes(data_sent);
for (int x = 0; x < data_size; x++)
if (data_sent[x] == 0x3f){
data_sent[x] = 0;
}

note: the c# is working and compiled but the c++ code stuck me from that error. Confused | :confused:

******************************
I just want to
know everything

Re: byte C# to C++

C#Coudou26-Jun-07 19:39

C#Coudou

26-Jun-07 19:39

I got it already. thanks

******************************
I just want to
know everything

Network speed detection

C#Coudou26-Jun-07 18:36

C#Coudou

26-Jun-07 18:36

Bros,

How to code the network speed detection?
What i mean is i want to detect the upload and download using clickbutton. When I press a button it will show to textbox1 the upload speed and textbox2 the download speed.
example:
TextBox1 = 42 kbps
TextBox = 54 kbps

Is anybody here how to do that? Much better if you can give me some links for basic.

Thanks in advance.

******************************
I just want to
know everything

Re: Network speed detection

Paul Conrad14-Jul-07 13:41

Paul Conrad

14-Jul-07 13:41

Send some packets of data of certain size (you decide how much data you want to transfer), see how long it takes to go up and come back, then report the results in the textbox.

"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus

ConnectionString

mikobi26-Jun-07 4:53

26-Jun-07 4:53

I am using Sql SErver 2000 Database and I begin to work with Visual c++ Net 2005;

How to to write SqlCommand::Connection to connect to SQl server 2000 in Visual c++ net 2005

I learn my self

led mike26-Jun-07 5:26

led mike

26-Jun-07 5:26

I see you have lots of Database development questions. Lucky for you there are a massive number of Database Articles here on CodeProject. Use the Navigation mechanisms on the site to find the Database Articles and look through them. I am sure the information you seek is in there.

Mark Salsbery26-Jun-07 5:55

26-Jun-07 5:55

In addition to led mike's reply, I think it's important to consult the documentation for the
platforms/systems/etc. that you're wanting to develop for.

For example, to connect to SQL Server, you'll probably want to use the SQL Native Client.
Connection string info can be found here: Using Connection String Keywords with SQL Native Client[^]

Mark

"Go that way, really fast. If something gets in your way, turn."

mikobi27-Jun-07 5:37

27-Jun-07 5:37

Mark Salsbery27-Jun-07 6:35

27-Jun-07 6:35

Does that work? Smile | :)

Mark

"Go that way, really fast. If something gets in your way, turn."

mikobi27-Jun-07 21:06

27-Jun-07 21:06

Yes, very well

Query with parameters

mikobi26-Jun-07 3:36

Re: Query with parameters

26-Jun-07 3:36

I am using Visual C++ NET 2005.

I want to know how to execute a query with parameters in my program

I learn my self

mikobi27-Jun-07 5:34

27-Jun-07 5:34

String^ strConnection;
String^ strString;
SqlConnection^ cprl = gcnew SqlConnection();
cprl->ConnectionString = "Persist Security Info=False;Integrated Security=SSPI;database=payroll05;server=SEM1;Trusted_Connection=Yes;" ;
// connectionString="Persist Security Info=False;Integrated Security=SSPI;database=Northwind;server=(local);"
// providerName="System.Data.SqlClient"
cprl->Open();
SqlCommand^ Cmd = gcnew SqlCommand();
Cmd->CommandText = "insert into barimpot(taux,minr,maxr)values(@taux ,@minr ,@maxr)";

SqlParameter^ para = gcnew SqlParameter();
para->SqlDbType = SqlDbType::Int;
para->ParameterName = "@taux";
para->Value = this->taux->Text::get();
Cmd->Parameters->Add(para);

SqlParameter^ param = gcnew SqlParameter();
param->SqlDbType = SqlDbType::Decimal;
param->ParameterName = "@minr";
param->Value = this->borneinf->Text::get();
Cmd->Parameters->Add(param);

SqlParameter^ parai = gcnew SqlParameter();
parai->SqlDbType = SqlDbType::Int;
parai->ParameterName = "@maxr";
parai->Value = this->bornesup->Text::get();
Cmd->Parameters->Add(parai);

Cmd->CommandType = CommandType::Text;
Cmd->Connection = cprl;
// ::MessageBox::Show("okkk2");
Cmd->ExecuteNonQuery() ;

MVPs

vibindia25-Jun-07 18:11

vibindia

25-Jun-07 18:11

Hi,

What does MVPs mean.

VIBIN

"Fool's run away,where angle's fear to tread"

Re: MVPs

Giorgi Dalakishvili25-Jun-07 20:35

Giorgi Dalakishvili

25-Jun-07 20:35

It means Microsoft Most Valuable Professional[^]

#region signature
my articles
#endregion

Re: MVPs

Mark Salsbery25-Jun-07 20:45

Re: Image GDI+ from a buffer

25-Jun-07 20:45

...and in sports, it's a Most Valuable Player.

I wonder if that's the same for Code Project MVPs?
Or is it Most Valuable Person, Professional,... Smile | :)

"Go that way, really fast. If something gets in your way, turn."

Image GDI+ from a buffer

Ahmed_Barakat25-Jun-07 5:56

Ahmed_Barakat

25-Jun-07 5:56

hi,
how can i construct an Image ( to be passed to a Graphics object later ) from a memory a buffer ?
lets say a loaded GIF file in a char * buffer

Thanks in advance

A.Barakat

led mike25-Jun-07 6:04

led mike

25-Jun-07 6:04

A.Barakat wrote:
lets say a loaded GIF file in a char * buffer

Don't do that. Load it into an Image type.

Re: Image GDI+ from a buffer

Mark Salsbery25-Jun-07 8:56

problem with unmanaged pointers

25-Jun-07 8:56

If you choose to ignore led mike's advice...

I think you could store in a MemoryStream and use Image.FromStream() to create the object later.
I'm not sure why though Smile | :)

Mark

"Go that way, really fast. If something gets in your way, turn."

Arris7425-Jun-07 5:46

Arris74

25-Jun-07 5:46

Hello,

I have an MFC application that i would like to mix with Managed C++.
I changed the compiler settings and everything compiles fine.
For the moment I did not write any managed code but I have the message as follows at execution:

"An unhandled exception of type 'System.TypeLoadException' occurred in ApplicationName.exe
Additional information: Could not load type _TREEITEM from assembly ApplicationName, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null."

This message occurs before execution of the function that returns a pointer.
I have put a breakpoint in it but it is never called.
I think it is unmanaged pointer problem because I have modified the function to return a reference to CWnd and everything was Ok.

below is the code snipped, Could please help me because I am 100% newbee with C++/CLI Confused | :confused:

Declaration

// Attributes
private:
CWnd* m_pView;

//Declaration of the function
CWnd* CreateTreeView();

Definition

//Constructor definition
BnBPaneView::BnBPaneView():m_pView(NULL){}


//definition of the function
int BnBPaneView::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
	if (CWnd::OnCreate(lpCreateStruct) == -1)
		return -1;
	
	
	m_pView = CreateTreeView();// error message here. The function is not called at all.
//Create view is a function that creates a treeview and uses a CTreeCtrl object.
	
etc..
.
.
.
}

Re: problem with unmanaged pointers

Mark Salsbery25-Jun-07 9:00