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Hi,
Thanks Luc. Yes, I'm aware that it is probably not a great idea to keep creating and disposing of the pens/brushes. I found in a previous application I'd written (in unmanaged C++) that it seemed to recreate the pen every time for some reason, even though I wasn't specifically telling it to do so. It kept crashing. Finally I gave up and simply created and deleted everything on each iteration. But I'll work on that again.
Mostly I'm just trying to understand the syntax/object model of managed C++ well enough to actually do some basic examples. My big goal at this point is to control where the drawing is done, which unfortunately you didn't mention in your reply.
The code examples I'm drawing from are from Msft VisualC++.Net by Templeman/Olsen (for anyone who is interested) and they are using the "Graphics" class to invoke the DrawLine method as you can see in the code. But how does this class know where to draw the line? Somehow it's assuming I want it drawn on the Form. What if I want it drawn somewhere else?
Thanks,
Jeff
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Hi Jeffrey,
I suggest you read points 1 and 3 once more.
The Paint handler must be wired to the Control you want to paint on.
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Hi,
Unfortunately I just can't find enough documentation on this subject to proceed at this point. I'll do some more digging...
Thanks,
Jeff
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what is wrong with myControl.Paint+=myPaintHandler; except for the fact that you want C++ syntax, mine is C#?
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Hi,
To me - and this may just reveal my ignorance - whether or not this is handled as a Paint event or simply placed within the timer sub doesn't really affect the central question which is how to get the brushes/pens to draw on the pictureBox and not the Form.
To get some idea I simply used the Designer code generator to create MouseDown and MouseUp events on the pictureBox.
This is what the code looked like:
this->pictureBox1->MouseUp += new System::Windows::Forms::MouseEventHandler(this, pictureBox1_MouseUp);
this->pictureBox1->MouseDown += new System::Windows::Forms::MouseEventHandler(this, pictureBox1_MouseDown);
then for the drawing I used this
private: System::Void pictureBox1_MouseDown(System::Object * sender, System::Windows::Forms::MouseEventArgs * e)
{
p1.X = e->X;
p1.Y = e->Y;
}
private: System::Void pictureBox1_MouseUp(System::Object * sender, System::Windows::Forms::MouseEventArgs * e)
{
p2.X = e->X;
p2.Y = e->Y;
Graphics* gr= CreateGraphics();
Pen* pen1 = new Pen(Color::Black);
gr->DrawLine(pen1, p1.X,p1.Y,p2.X,p2.Y);
gr->Dispose();
}
But this is still drawing on the Form, not the pictureBox. Puzzling.
Jeff
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Jeffrey Webster wrote: Graphics* gr= CreateGraphics();
is completely wrong:
1. you are getting a Graphics associated with your Form, not your PictureBox (how is the Graphics to know you want to paint on the PictureBox??)
2. you don't need to create a Graphics at all, you get one for free in any Paint handler.
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Okay then send me some code, an example, something I can work with. I think by now we know that simply admonishing me for not using a Paint handler is not helping me.
Thanks,
Jeff
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C# example (not tested):
private Panel panel;
private bool paintRectFlag=true;
private Rectangle rect=new Rectangle(20, 20, 300, 200);
private Pen rectPen=Pens.Black;
…
public Form1() {
InitializeComponents();
panel=new Panel();
panel.Paint+=panelPaintHandler;
Controls.Add(panel);
}
…
protected void panelPaintHandler(object sender, PaintEventArgs e) {
Graphics g=e.Graphics;
if (paintRectFlag) g.DrawRectangle(rectPen, rect);
}
protected void buttonClickHandler(object sender, EventArgs e) {
paintRectFlag=!paintRectFlag;
panel.Invalidate();
}
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Thanks for the code.
As I understand it, the actual drawing occurs here:
protected void panelPaintHandler(object sender, PaintEventArgs e) {
Graphics g=e.Graphics;
if (paintRectFlag) g.DrawRectangle(rectPen, rect);
Which draws to a panel, which I'm assuming is a sort of generalized/abstract screen object. Presumably this would be rendered according to the needs of some Form (or other) object when invoked?
So if you (were to) run this, would it draw a rectangle? Or do you need additional code to make it "work"?
Thanks,
Jeff
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Hello All,
I am trying to convert a list of Strings in LPWSTR* array. I am using the following way to convert it. But here the problem occurs in the returning array items. It contains all the elements same in the array. I found the problme is due to memset() which updates the memory address everytime same as earlier. Please help me out----
for(DWORD i = 0; i < itemIds->Count; i++)
{
ATL::CComBSTR itemWChar;
itemWChar = ::GetAtlBstr(itemIds[i]);
WCHAR _itemWChar[_MAX_PATH];
memset(_itemWChar, 0, sizeof(_itemWChar) / sizeof(_itemWChar[0]));
memcpy(_itemWChar, static_cast(itemWChar), itemWChar.ByteLength());
items[i] = _itemWChar;
}
ANURAG VISHNOI,
Sr. Software Engineer,
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The memset() should have no effect here (nor is it necessary).
Plus, you've calculated the number of bytes to set incorrectly...
it should be sizeof(_itemWChar), not sizeof(_itemWChar) / sizeof(_itemWChar[0])
What are "itemIds" and "items" (what are their declared types)?
This is the part that looks fishy to me:
memcpy(_itemWChar, static_cast(itemWChar), itemWChar.ByteLength());
items[i] = _itemWChar;
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.freetls.fastly.net/script/Forums/Images/coffee.gif)
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I'm writing a diagnostic tool in Visual C++. It's a GUI. I need to be able to have the program determine whether or not it needs to be loaded with admin privileges on Vista. The diagnostic tool works flawlessly in XP 32 bit, and it would work flawlessly on 64 bit if I could determine how to verify whether the system is 32 bit or 64 bit by redirecting the directory the batch files are automatically written to. Could anyone help me with figuring out the code used to first verify the OS and whether it's 32 or 64 bit? After that, possibly how to bypass UAC on Vista so it has the administrator rights when running batch files?
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Thanks for that first link, that will help tremendously. What I meant by bypass UAC on Vista is to allow the program to execute batch files as the administrator. Some commands, such as resetting tcp/ip, require the "elevated" command prompt.
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Something like this?
System::Diagnostics::Process ^process = gcnew System::Diagnostics::Process();
process->StartInfo->FileName = "cmd.exe";
process->StartInfo->Arguments = "/c c:\\mybatchfile.bat";
process->StartInfo->Verb = "runas";
process->Start();
Mark Salsbery
Microsoft MVP - Visual C++
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I'll have to try this, would this be Vista only or would it work on XP as well? With the runas verb, would that prompt the user or have it automatically do it?
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turkmeistr1 wrote: With the runas verb, would that prompt the user
The way I showed it, yes, it will prompt.
System::Diagnostics::Process::StartInfo, as well as another System::Diagnostics::Process::Start() overload,
also have user name and password properties if you know an administrative user/password in advance.
turkmeistr1 wrote: I'll have to try this, would this be Vista only or would it work on XP as well?
As far as I know it should work on XP...try it - you can always just test with notepad or
something...
System::Diagnostics::Process ^process = gcnew System::Diagnostics::Process();
process->StartInfo->FileName = "c:\\windows\\system32\\notepad.exe";
process->StartInfo->Verb = "runas";
process->Start();
Mark Salsbery
Microsoft MVP - Visual C++
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Awesome, that works beautifully, final question, is there a way to verify if it's running on XP or Vista? I only want it to pull up the Run As prompt if it's Vista, otherwise it's not entirely necessary.
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turkmeistr1 wrote: is there a way to verify if it's running on XP or Vista?
I use something like this:
static public bool OsIsAtLeastVista
{
get
{
bool ret = false;
System.OperatingSystem osInfo = System.Environment.OSVersion;
if (osInfo.Platform == System.PlatformID.Win32NT)
{
if (osInfo.Version.Major > 5)
{
ret = true;
}
break;
}
return ret;
}
}
Mark Salsbery
Microsoft MVP - Visual C++
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I get a lot of errors when using System.OperatingSystem, if I change it to System::OperatingSystem it works up unto the point of System::Environment.OSVersion, what should I use for that last dot there? The :: doesn't work for that, Platform, or Win32NT or Version.Major.
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The code I posted was C#, sorry.
Use :: and -> where necessary to convert to C++/CLI.
Mark Salsbery
Microsoft MVP - Visual C++
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I ripped the code from a larger property implementation and left some
artifacts. Here's fixed, in C++/CLI:
bool ret = false;
System::OperatingSystem ^osInfo = System::Environment::OSVersion;
if (osInfo->Platform == System::PlatformID::Win32NT)
{
if (osInfo->Version->Major > 5)
{
ret = true;
}
}
return ret;
Mark Salsbery
Microsoft MVP - Visual C++
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YES! You are the greatest. Thank you so much for all of your help!
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Grr, I keep hitting speed bumps! How would I be able to do file stream from within the app to write the batch file to a directory within the program files? It's saying that access was denied on Vista, it works perfectly fine in XP. I can force the program to run as administrator, but it still doesn't work when trying to do file stream to write to a file.
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Hi,
My current project is to make wrapper classes of legacy mfc codes. I could easily marshal the String^ to CString like this:
bool LoadFile(String^ strPath)
{
// from managed to unmanaged using C++ Interop marshaling
pin_ptr<const wchar_t> pstrPath = PtrToStringChars(strPath);
// unmanaged declaration: bool LoadFile(CString path);
return m_pLegacyClass->LoadFile(pstrPath);
}
But string array is not a simple case. I marshaled all array members then copied the members to unmanaged memory. Here is the code.
bool LoadFiles(array<String^>^ arrayAviFilePath, int nAviFile)
{
// Array to marshal String^
array<IntPtr>^ arrayMarshalString = gcnew array<IntPtr>(nAviFile);
// Initialize unmanaged array
IntPtr arrayUnmanagedString = Marshal::AllocHGlobal(IntPtr::Size * nAviFile);
for (int i = 0; i < nAviFile; i++)
{
// Marshaling String^ to IntPtr
arrayMarshalString[i] = Marshal::StringToHGlobalUni(arrayAviFilePath[i]);
// Write to unmanaged memory
Marshal::WriteIntPtr(arrayUnmanagedString, i * IntPtr::Size, arrayMarshalString[i]);
}
// Use unmanaged array here
CString *pArrayAvi = static_cast<CString *>(arrayUnmanagedString.ToPointer());
bool bReturn = m_pLegacyClass->LoadFiles(pArrayAvi, nAviFile);
// Free unmanaged memory now
for (int i = 0; i < nAviFile; i++)
Marshal::FreeHGlobal(arrayMarshalString[i]);
Marshal::FreeHGlobal(arrayUnmanagedString);
return bReturn;
}
// legacy declaration
bool LoadFiles(CString arrayAviFilePath[], int nAviFile);
It works well anyway but is this best way?
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