Is there way to check whether a Form has a Form Border? (by handle)

Question

I want to check whether a form has a Form Border by its handle. And, the handle is from the another Application.

How can I handle this? Please help me.. Thanks!

Windows Forms? Native Win32? Something else? -- Please note that C# as a *language* doesn't know anything about handles and windows etc. so your question must be about a particular UI framework. Please tag accordingly. — stakx - no longer contributing, Jul 16 '12 at 21:22
P.S. Win32 does not even distinguish between windows and controls. Technically, they are all "windows", albeit ones with differing attributes. — stakx - no longer contributing, Jul 16 '12 at 21:24
hmm.. i Just want to know whether it has a FormBorder or not. And the handle is from another Application. — jn4kim, Jul 16 '12 at 21:27
@jn4kim: Then that should be your question. As stakx said, controls themselves are windows. — Ed S., Jul 16 '12 at 21:32
@jn4kim: My question still stands. It seems you're talking about Winforms. But what if that other application is native code, or WPF? The notion of a `FormBorder` *might* be meaningless with these... — stakx - no longer contributing, Jul 16 '12 at 21:35

Tergiver · Accepted Answer · 2012-07-17T17:40:58.747

2

[DllImport("user32.dll")]
extern static int GetWindowLong(IntPtr hWnd, int nIndex);

const int GWL_STYLE = -16;
const int WS_BORDER = 0x00800000;  // thin border
const int WS_THICKFRAME = 0x00040000;  // sizing (thick) border

public static bool NativeWindowHasBorder(IntPtr hWnd)
{
     return (GetWindowLong(hWnd, GWL_STYLE) & (WS_BORDER | WS_THICKFRAME)) != 0;
}

edited Jul 17 '12 at 17:40

answered Jul 16 '12 at 22:20

Tergiver

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Shouldn't it be `GetWindowLongPtr` if you use `IntPtr`? Or `GetWindowLong` if you use `Int32`? Or: Why the `.ToInt64()` conversion? – stakx - no longer contributing Jul 17 '12 at 16:58
@stakx Yes. I couldn't remember how to get window styles off the top of my head and pasted that from someone who did it wrong. I've corrected it. – Tergiver Jul 17 '12 at 17:42
1

`GetWindowLongPtr` is not necessary as the WS_BORDER and WS_THICKFRAME bits are both within the first 32. – Tergiver Jul 17 '12 at 17:46

Jonathon Reinhart · Answer 2 · 2012-07-16T21:52:55.330

0

Controls themselves don't actually have a handle. Control.Handle actually returns it's parent window's .Handle.

From MSDN for Control.Handle:

Gets the window handle that the control is bound to.

If you look at the decompiled source for Control, you'll see:

internal IntPtr HandleInternal
{
  get
  {
    return this.window.Handle;
  }
}

Edit

What I've stated above is completely incorrect. I'm leaving it for historical sake.

One can prove this very easily by putting a Button on a Form, and looking at the IntPtr Handle value for them. They are different.

edited Jul 16 '12 at 21:52

answered Jul 16 '12 at 21:23

Jonathon Reinhart

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Uhm, is it a good idea / legal to post decompiled framework code...? I don't want to FUD you but this might be worth a thought. PS: That decompiled code is almost meaningless without more knowledge about what `this.window` mean. – stakx - no longer contributing Jul 16 '12 at 21:30
Thankyou for your answer but this is not what i want to know, i think i did not write the question correctly – jn4kim Jul 16 '12 at 21:32
@stakx I think it's pretty clear that the Control itself doesn't have a handle, and instead, it's returning it's parent window's handle. Just as the MSDN text describes. – Jonathon Reinhart Jul 16 '12 at 21:34
1

@Jonathon: -1. I believe your answer is incorrect, and I am certain that controls have a handle, too. Your answer actually supports this: Controls are technically also "windows" in Win32 API parlance (and Winforms is based on Win32), so I think you're mistaken when you assume that "window handle" means "parent window handle". Instead the `Control.Handle` "window handle" refers to the internal `HWND` of the control. – stakx - no longer contributing Jul 16 '12 at 21:40
@stakx You are absolutely correct. I just did a quick test, and indeed, the values of `IntPtr Handle` are different between a `Form` and a `Button` on that `Form`. Having used Spy++ 100's of times before, I should have thought of this. – Jonathon Reinhart Jul 16 '12 at 21:51

Is there way to check whether a Form has a Form Border? (by handle)

2 Answers2