This is my code in order to get the name of the item which has been selected in my CListViewCtrl:
LVITEM item = { LVIF_PARAM };
CString itemText;
clistViewCtrl.GetSelectedItem(&item);
clistViewCtrl.GetItemText(item.iItem, item.iSubItem, itemText);
Note that this code is working. I recently did another project, where I grabbed the name in exactly this way, however, I had no problems there with any assertion fails.
When I execute this with my current project, I always get a debug assertion:
"File: ... atlctrls.h"
Line: 3242
Expression: (GetStyle() & 0x0004) != 0
Even though the expression already states it pretty much, here is the line causing the failure:
ATLASSERT((GetStyle() & LVS_SINGLESEL) != 0);
I have barely any idea what the problem is. As I said, the exact same code worked on my other project, and I just went through both, trying to find any differences which could cause this behaviour, but nothing caught my eye.
Honestly, I don't even know if this is related to my code at all, considering the two compared elements seem to be predefined.
My first guess would have been that this part is being called before the items are created, but all items in the listview are created at the point I try to call this code passage.
Can anyone point me to a solution?
Your control is not created with style flag LVS_SINGLESEL. So calling GetSelectedItem is causing an assert. In case of multi selection use GetFirstSelectedItem and GetNextSelectedItem instead of GetSelectedItem. For single selection you can continue useing GetSelectedItem, but you have to add LVS_SINGLESEL style flag to your control.
Related
This is my first question ever posted, so please let me know if there is anything that needs changes in my post :)
I am currently working on a dialog that is supposed to let the user change the background-color for some signal plotting. The "wxColourPickerCtrl" seems to do exactly what I need. Since there are multiple plots/pictures to be manipulated, the ColourPickerCtrls are initialized in a loop with the chosen background color as the default value:
for (const auto& [signalName, signalProperties] : properties)
{
wxColourPickerCtrl* selectBackgroundColor = new wxColourPickerCtrl(this, signalProperties.first, signalProperties.second.backgroundColor, wxDefaultPosition, wxDefaultSize);
}
"this" is an object of type SignalPropertiesDialog, which is directly inherited from wxDialog.
I have left out all the necessary sizer stuff, since it's not relevant for the problem (at least imo). "properties" is structured as follows:
std::map<std::string, std::pair<int, GraphPicture::Properties>> signalProperties_;
where GraphPicture::Properties contains the properties I want to manipulate:
struct Properties
{
wxColour backgroundColor{ *wxWHITE };
wxColour lineColor{ *wxBLACK };
int linewidth_px{ 1 };
bool isShown{ true };
};
The application successfully builds but immediately crashes on startup while generating those color picker objects.
wxIshiko has uploaded multiple tutorials and code snippets as examples for various wxWidgets controls, including the wxColourPickerCtrl. So I downloaded the sample code and tried to run it. Surprisingly, it worked.
While running through the code step by step I noticed the following difference:
The wxColourPickerCtrl is based on wxPickerBase. The wxPickerBase is created by calling the constructor of wxColourPickerCtrl (what I am actually doing in my code). During the construction of the wxPickerBase, the desired color is called by the name wxColourDataBase::FindName(const wxColour& color) const where the wxColourBase itself is instantiated. This is where the difference is:
When running the code snippet by wxIshiko, wxColourDataBase is instantiated correctly including the member m_map of type wxStringToColourHashMap* which is set to be NULL.
When running the code written by myself, wxColourDataBase is not correctly instantiated, and thus the member m_map is not set to be NULL, which leads to to the crash.
I have the feeling that there is nothing wrong with the way I set up the wxColourPickerCtrls. I somehow think there is a difference in the solution properties of the projects. I checked those but was not able to find any relevant differences.
I would really appreciate any hint or help since I am completely stuck on that problem.
Thank you very much in advance and have a good one,
Alex
EDIT:
I attached a screeny of the call stack.
Call stack
When does this code run exactly? If it is done after the library initialization (which would be the case, for example, for any code executed in your overridden wxApp::OnInit()), then wxTheColourDatabase really should be already initialized and what you observe should be impossible, i.e. if it happens it means that something is seriously wrong with your library build (e.g. it doesn't match the compiler options used when compiling your applications).
As always with such "impossible" bugs, starting with a known working code and doing bisection by copying parts of your code into the working version until it stops working will usually end up by finding a bug in your code.
New to Go and building a simple LRU cache in Go to get used to syntax and Go development.
Having an issue with the MoveToFront list method, it fails on the following check in the MoveToFront body
if e.list != l || l.root.next == e
I want to move the element (e) to the front of the list when I retrieve it from cache , like this
if elem, ok := lc.entries[k]; ok {
lc.list.MoveToFront(elem) // needs fixing
return elem
}
return nil
The Code can be seen here on line 32 the issue occurs
https://github.com/hajjboy95/golrucache/blob/master/lru_cache/lrucache.go#L32
There seem to be two problems, to me. First, this isn't how the List data type is meant to be used: lc.list.PushFront() will create a List.Element and return a pointer to it. That's not fatal, but at the least, it is kind of annoying—the caller has to dig through the returned List.Element when using Get, instead of just getting the value.
Meanwhile, presumably the failure you see is because you remove elements in Put when the LRU-list runs out of space, but you don't remove them from the corresponding map. Hence a later Put of the just-removed key will try to re-use the element in place, even though the element was removed from the list. To fix this, you'll need to hold both key and value. (In my simple experiment I did not see any failures here, but the problem became clear enough.)
I restructured the code somewhat and turned it into a working example on the Go Playground. I make no promises as to suitability, etc.
I am trying to use the Google geocoder to do a reverse-geocoder lookup. I am running the exact same command on 8 values, and I am only having an error on two of them, which has me confused as one of the failing values is identical to one of the working values. (The 'working' values aren't really working- they still return a value of undefined from the 'formatted_address' field, but they aren't throwing errors). The command that I am running is as follows:
geocoder.geocode({latLng: new google.maps.LatLng(machineList[i].y, machineList[i].x)}, function(results, status) { address = results[0]; });
I am receiving a type error from Javascript, claiming that results is null. I'm not sure why this is happening. Any ideas?
Well, it turns out this was a timing issue. The geocode() command was taking longer to complete for certain locations than for others, which caused the value to show up as null. I ended up eliminating the problem by moving all the subsequent code into the callback function (I hadn't done this earlier because the whole thing is running inside of a loop, and I was having some difficulty getting it to pass in the iterator as a parameter). Now everything seems to be working well and the locations are showing up as they should.
So I'm trying to make use of a GtkSourceView in C++ using GtkSourceViewmm, whose documentation and level of support give me the impression that it hasn't been very carefully looked at in a long time. But I'm always an optimist :)
I'm trying to add a SourceView using some code similar to the following:
Glib::RefPtr<gtksourceview::SourceLanguageManager> source_language_manager = gtksourceview::SourceLanguageManager::create();
Glib::RefPtr<gtksourceview::SourceLanguage> source_language = Glib::wrap(gtk_source_language_manager_guess_language(source_language_manager->gobj(), file, NULL));
Glib::RefPtr<gtksourceview::SourceBuffer> source_buffer = gtksourceview::SourceBuffer::create(source_language);
gtksourceview::SourceView* = m_source_view = new gtksourceview::SourceView(source_buffer);
m_vbox.pack_start(*m_source_view);
Unfortunately, it spits out the warning
(algoviz:4992): glibmm-WARNING **:
Failed to wrap object of type
'GtkSourceLanguage'. Hint: this error
is commonly caused by failing to call
a library init() function.
and when I look at it in a debugger, indeed the second line above (the one with the Glib::wrap()) is returning NULL. I have no idea why this is, but I tried to heed the warning by adding Glib::init() to the begining of the program, but that didn't seem to help at all either.
I've tried Google'ing around, but have been unsuccessful. Does anyone know what Glib wants me to init in order to be able to make that wrap call? Or, even better, does anyone know of any working sample code that uses GtkSourceViewmm (not just regular GtkSourceView)? I haven't been able to find any actual sample code, not even on Google Code Search.
Thanks!
It turns out, perhaps not surprisingly, that what I needed to init was:
gtksourceview::init();
After this, I ran into another problem with one of the parameter to gtksourceview::SourceLanguageManager, but this was caused by a genuine bug which I subsequently reported and was promptly fixed. So everything's working great now!
I use gtkmm. Typically you have to initialize things with something like :
_GTKMain = new Gtk::Main(0, 0, false);
Of course do not forget :
delete _GTKMain;
Check here for details :
http://library.gnome.org/devel/gtkmm/2.19/classGtk_1_1Main.html
(Sorry but the link option does not work ...)
Hi I have just started using C++ today, and I am working on checkboxes. I have tried using CheckBox1->Checked in an if statement or whatever, but it isn't working.
The error is:
Error 2 error C2227: left of '->Checked' must point to class/struct/union/generic type
EDIT: The Code is:
void function ()
{
if (1001->Checked)
{
Sleep(2000);
}
}
Without seeing some of your code, it's very difficult to offer targeted assistance.
However, that error message usually comes about because the item you're de-referencing is not a pointer.
Check to ensure it's of the correct type. It should be something along the lines of:
tCheckBox *CheckBox1;
One possibility is that you've declared it not as a pointer to the checkbox but as a checkbox itself:
tCheckBox CheckBox1;
Note the lack of the asterisk there that would otherwise mark it as a pointer. In that case, you would use CheckBox1.Checked rather than CheckBox1->Checked, if it's allowed by the framework (this isn't standard C++ since that beast has no concept of GUI libraries).
If that doesn't help, please post the code so we can offer better suggestions.
Update:
if (1001->Checked) ?????
1001 is not a pointer - it's not a variable of any description, it's an integer constant.
You need to declare and use a variable of some description. First step is, I think, to read up on the documentation for your framework and/or get some sample code that does compile and work, basing your initial work of that.
Use CButton::GetCheck() to determine the state of the checkbox - like so...
CButton* pButton = (CButton*) GetDlgItem(IDC_CHECKBOX_RESOURCE_ID);
if ( BST_CHECKED == pButton->GetCheck() )
{
// button is checked
}