changng object properties in C

[Bad5887]

how do you change a object's properties in 32 bit C? i haev the lcc win32 compiler, it's awesome but i'm still kinda new, please give me an examople how to dothis:

How do you enable/disable a button in C?

I have Visual C++ and here is how you disable a button. Right-click the Button, select properties, and click on the Disabled Checkbox.

[parksie]

What do you mean, enable/disable. Is that a button in a dialogue box? If you are using anything like MFC/OWL then it's different. If you are using 'bare-foot' API, then look up the SendDlgItemMessage function, and send the WM_ENABLE message. Disabling is slightly strange, and you'll need to check MSDN for that. http://msdn.microsoft.com/library

--- one edit later ---
sorry meg, was writing my reply at the same time as you!
...oh well. If he's not using MSVC then that won't work.


[Edited by parksie on 07-01-2000 at 10:47 PM]

[Bad5887]

megatron... i ment at runtime, yeah i'm using bare API, cas my compiler is LCC win32 C compiler. i also have vc++ 6 prof edition but lcc makes nice small fast exe's and does all the same things.


i know that is the api call but can u give me and example pleaseeeeeeeee, thanks

Use the EnableWindow API. I can tell you to do it in VC++. First, when you create your Button, you must add a Member Variable using the Class Wizard. Call it m_bTest.

Put this code in another Button.

void CDialogtestDlg::MyButton() 
{
	// Disable the Button
	m_bTest.EnableWindow(FALSE);
}

[Bad5887]

i don't know VC++, i don't even knwo what the heck were thoughs :: for?

[parksie]

In C++, when you create an object, by definition it has its own 'namespace'. For example:

namespace A {
    int i;
    string mystr;
}

namespace B {
    int i;
    string anotherstring;
}

void function() {
    int j;
    string x;
    j = i;             // WRONG: which namespace?
    j = A::i;          // RIGHT: select from namespace A
    j = B::i;          // RIGHT: select from namespace B
    x = mystr;         // RIGHT: no need to select namespace
    x = anotherstring; // RIGHT: no need to select namespace
}

So, when you define your class:

class MyClass {
public:
    MyClass();
    virtual ~MyClass();

    void MyFunction(int iParam);
    int m_iMyMemberVariable;
}

They are now under the namespace 'MyClass'.

So, to define the functions:

MyClass::MyFunction(int iParam) {
    m_iMyMemberVariable = iParam;
}

The '::' selects the namespace, so the compiler knows that you are defining the 'MyFunction' function under namespace 'MyClass'. There is no need to select the namespace for m_iMyMemberVariable because that is the default namespace for that function now.

Back to your original question, though, Megatron was using MFC (Microsoft Foundation Classes) which make Windows programming a lot easier. The CWnd::EnableWindow function is a wrapper for the API EnableWindow function, which can be accessed by ::EnableWindow (::XX means select XX out of the default namespace, which everything which is not already in a namespace ends up in). This is defined as:

    void EnableWindow(HWND hWindow, BOOL bEnableFlag);

You need to pass the HWND of the button, and either 1 or 0 for bEnableFlag to enable or disable respectively.



[Edited by parksie on 07-02-2000 at 05:30 AM]