Access MDI child controls in C++ Builder

Hi,
Yes if you try to access the form class directly it results in an access violation. Just need the code that allows me access to the controls of an existing child from the parent, instead of creating a new one.

Thanks for the comment

Use PostMessage

In what context?
Could you elaborate a bit more or give an example?

Use PostMessage when you need to notify the parent or child forms or even transmit a data. Any form can handle only one message at a time, so it will work without access violation errors.

Thanks for the reply. So what would the BCB code look like if I wanted to hide a panel on the MDI Child from a button on the MDI parent?

The code hiding the panel will be the child. The child is supposed to receive a message and hide the panel.
I do not have any BCB installed (for few years already) and cannot provide you with a code - I need to test the code I post.
Here is a not bad tutorial:
http://www.functionx.com/bcb/topics/introwindows.htm

http://www.functionx.com/bcb/index.htm

and you can find ShowWindow(Panel1->Handle, ... there.

Ive had a look and cant get it to do the things I require. When I create a client with

TMyForm* MyFrm = new TMyForm(this)

I can then access all the controls on that form calling MyFrm ->......
Only problem is I have to create a new child, using the above code, every time I want to do this.
I want to be able to declare the child once and then access it whenever I want, without using the 'new' command to recreate every time

http://bcbjournal.org/articles/vol2/9805/MDI_made_easy.htm

Actually all your forms have a parent/owner - so you can use GetChildren?

GetWindow with GW_CHILD will find all child windows (forms). These windows may have IDs, names, whatever to be identified.

MSDN: http://msdn.microsoft.com/en-us/library/ms633515(VS.85).aspx

Hi,

Thanks for the info. Have checked the links, couldnt find the exact code for what I wanted to do but I have worked it out now.

For anyone else wanting to do the same -

Declare the child form in the parents declarations area
TMyForm* MyFrm;

Then to create the child
MyFrm=new TMyForm(this);

To acces its controls from the parent
MyFrm->......

Cheers,
Kris

Right. :)
It is C++.
Actually I've said it here: ID:25601042

Thanks for the help with this, I split the points as I thought you both helped me out.

itsmeandnobodyelse:

Thanks for the extra info. Could you give me an example of how the header code would look?

Cheers,
Kris

// mymdipar.h
...
// forward declaration of form class
class MyForm;

class MyMDIParent : public T...  
{
     ....
public:
      // in all the constructors init the member pointer to NULL
      MyMDIParent(...)  :  myFrm(NULL) {}      
      ~MyMDIParent() { delete myFrm; }
private:
      MyForm * myFrm;    
};

// myform.h
...

class MyForm : public TForm
{
     ...
public:
     void doSomeWhatWithControls();
};