Incorrect parameter for custom event handler

c++ builder

    Sponsored Links

    Next

  • 1. why does Image1->Picture->Bitmap->Width and Height not following the Image1->Width and Height?
    bryan wong wrote: > Image1 is TImage, Please do not cross-post. There is a reply in the other group. Hans.
  • 2. Modify TValueListEditor to expose edit window property
    Hi All, This would be the first time I am creating a component. I've done a bit of research, but don't understand everything I am reading. Anyway, I want to control the color of the cell in a TValueListEditor when it is in edit mode. As best as I can figure, this property would be controlled by InPlaceEditor->Brush->Color would declaring this in my derived component be somehting like: __published: __property TColor cEditColor = {read=InPlaceEditor->Brush->Color, write =InPlaceEditor->Brush->Color, default=clWindow}; or am I so far off base I'm on a golf course? Thanks Stephan
  • 3. How could I put a global variable in a dll ?
    Hello, I need to declare a global var inside dll: namespace ZQuery { static AnsiString sSGBD = ""; extern "C" void _stdcall zDLLInit(char * szSGDB) { sSGBD = AnsiString(szSGDB); } } in app call: ZQuery::zDLLInit("ORACLE"); It compile but the global var sSGBD is blank !!! regards
  • 4. Save property
    I found that there is some bug in C++builder sometime my new property cannot be saved so simple __published: __property bool NewPageActive={read=FNewPageActive,write=FNewPageActive}; Would you tell me how to force to save the property NewPageActive Value? Thank you
  • 5. Message Processing...
    I am currently setting flags in a timed loop to notify my software that it is time to process certain data. I have read extensively to find the best way to do this and have been using a Windows message handling routine and a user WM message. Here is my routine... void __fastcall TForm1::Loop(TMessage &Msg) { while(!WantToQuit) { ProcessData(); Application->ProcessMessages(); } } ProcessData() uses these flags set inside the message loop to process the data. Now for my question: If I use an open file dialogue, all of my processing in side my message handler stops, while my timing loop still continues to fire. This causes me to miss data that I receive within my timing loop, since the data is never processed. Does anyone have an idea of how I may be able to fix this? I have thought about spawing threads to handle the background data handling that the flags currently notify the processData() function to handle, instead. Is the thread route a better idea? All I am trying to do is process data that is received via an RS232 port outside of the timed loop and not within the loop. Any suggestions would be very appreciated.

Incorrect parameter for custom event handler

Postby Myles Rippenhagen » Wed, 26 Oct 2005 02:43:50 GMT

Hi,

I have created several custom components and generally have had great 
success with them, but I am currently running into a problem where when I 
double-click on a published custom event (on the "Events" tab of the "Object 
Inspector" in the IDE), the inserted method declaration contains the wrong 
variable name.  The signature matches another, similar custom event, and it 
seems to be picking up the parameter name from this other definition.  I 
have double-checked that I am referencing the correct typedef in the 
definition of my custom component and I didn't see any problem.  I am using 
BCB6 Enterprise on WinXP.  Following are the important bits of the code.

...
typedef void __fastcall (__closure *BeforePostEvent) (TObject* Sender, bool 
&CanPost);
typedef void __fastcall (__closure *OnPutToDatabaseEvent) (TObject* Sender, 
bool &DoDefault);
...
private:
   OnPutToDatabaseEvent FOnPutToDatabaseEvent;
...
__published:
   __property OnPutToDatabaseEvent OnPutToDatabase = 
{read=FOnPutToDatabaseEvent, write=FOnPutToDatabaseEvent};
...

When I double-click on the "OnPutToDatabase" event in the IDE, the inserted 
code labels the bool parameter "CanPost" instead of "DoDefault".  It appears 
to just pick up the first typedef with a matching signature instead of using 
the typdef that I specified.

Any suggestions??



Re: Incorrect parameter for custom event handler

Postby Remy Lebeau (TeamB) » Wed, 26 Oct 2005 03:12:24 GMT







That is a long-standing known issue.  The OI matches events by signatures
only, not names.  You have two different events that have the exact same
signature (return value, calling convention, parameter data types, and
parameter ordering).  The OI always generates code using the first event
type that matches the required signature.


That is exactly why you are seeing what you have described.  There is
nothing you can do to prevent the OI from behaving that way.  You will just
have to change the signature of one of your events so that they no longer
match each other.


The OI does not care about typedefs.  It only cares about signatures.


Gambit



Similar Threads:

1.Why event handler first parameters are incorrect

I noticed that DataGridView CellValidated() and other event handler first 
parameter is object:

        Grid.CellValidated+=new 
DataGridViewCellEventHandler(Grid_CellValidated);
...

        void Grid_CellValidated(object sender, DataGridViewCellEventArgs e) 
{
....
}

Why ? Correct signature must be

void Grid_CellValidated(DataGridView sender, DataGridViewCellEventArgs e) {

Andrus. 

2.Custom event handler

Hello, all.  I am trying to develop my first component and I am trying to
figure something out.  I created a MouseMove event handler for my component
(TMyComponent::MouseMove) and it works fine.  I added my component to a new
project (TMyComponent *MyComponent1) and I want perform a task in the
MyComponent1MouseMove event.  My problem is that the TMyComponent::MouseMove
function is executing, but the TForm1::MyComponent1MouseMove function is
not.  I set the OnMouseMove event to MouseMove for the MyComponent1
instance, but it still only calls the component handler, not the custom
handler.  Why won't it call my custom handler?  Actually, I will need both
functions to execute.  Will I need to explicitly call
TMyComponent::MouseMove() from within the TForm1::MyComponent1MouseMove
function to get both to execute?  Any feedback will be greatly appreciated.

Thanks,

Mark


3.Custom event handlers in .NET Winforms

4.Custom Event Handler

I am getting an error down below, this same code works in VB, what gives?

private void Form1_Load(object sender, System.EventArgs e)

{




System.Windows.Forms.LinkLabel l = new System.Windows.Forms.LinkLabel();

FileSystemWatcher watcher = new FileSystemWatcher();

watcher.Path = @"C:\TempFolder";

watcher.Filter = "*.txt";

//error here: Cannot implicitly convert type System.EventHandler to
FileSystemWatcher,

watcher.Created += new System.EventHandler(OnCreated);

watcher.EnableRaisingEvents = true;





}

private void OnCreated(object sender, System.EventArgs e)

{

MessageBox.Show("yo");











}


5.Custom event handlers and searching a listview

6. Passing in a OnMouseDown/OnMouseUp event handler as a parameter of a function

7. How to pass more than two parameters in the event handler

8. TADODataset.Parameters.Refresh results in incorrect parameter names



Return to c++ builder

 

Who is online

Users browsing this forum: No registered users and 91 guest