GetDeviceState() problems

    
#include <dinput.h>

class CDInput
{
public:
	int DI_Init(HINSTANCE h, HWND hwnd );
	int DI_Shutdown();
	int WINAPI  GetKey();	//key input

private:
	LPDIRECTINPUT7			DI;			
	LPDIRECTINPUTDEVICE7	DI_Key;						
	BYTE	buffer[256];
};						

int WINAPI CDInput::GetKey()
{
	HRESULT hr = DI_Key->GetDeviceState(sizeof(buffer), (LPVOID)&buffer);

	if(buffer[DIK_ESCAPE] & 0x80)
		return true;
	else
	return false;
}
CDInput::DI_Init(HINSTANCE h, HWND hwnd )
{
    // Create Direct Input

    if ( DirectInputCreateEx( h,			// Window Instance

        DIRECTINPUT_VERSION,						// Direct Input Version

        IID_IDirectInput7,							// Version 7

        (void**)&DI,								// Direct Input

        NULL ) )
    {
    return(false);									// Couldn''t Initialize Direct Input

    }

    // Create The Keyboard Device

    if ( DI->CreateDeviceEx( GUID_SysKeyboard,	// Define Which Device To Create (KeyBoard,Mouse Or Joystick)
        IID_IDirectInputDevice7,					// Version 7

        (void**)&DI_Key,							// KeyBoard Device

        NULL ) )
    {
		// Couldn''t Create The Keyboard Device

        return(false);								// Failed, Return False
    }

    if ( DI_Key->SetDataFormat(&c_dfDIKeyboard) )	// Set The Keyboard Data Format

    {
		// Couldn''t Set The Data Format

        return(false);								// Failed, Return False
    }

    // Set The Cooperative Level

    if ( DI_Key->SetCooperativeLevel(hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE) )
    {
		// Couldn''t Set The Cooperative Level

        return(false);								// Failed, Return False
    }

    if (DI_Key)									// Did We Create The Keyboard Device?

        DI_Key->Acquire();						// If So, Acquire It
    else
        return(false);								// If Not, Return False

	return true;
}

CDInput::DI_Shutdown()
{
    if (DI)
    {
        if (DI_Key)
        {
            DI_Key->Unacquire();
            DI_Key->Release();
            DI_Key = NULL;
        }
        DI->Release();
        DI = NULL;
    }
	return true;
}