VB 控件使用问题,高手请进 30
通过引用的方式(dim withevents a as A),可以new出来对象,调用其中的方法,一般的方法是正常的,但是其中有个监听USB拔插的方法无法响应。
通过部件的方式调用,将部件拖到窗体里,则所有的方法都是正常的。但是这种方式有个问题:如果用户没有安装这个控件,打开程序的时候就会报错。
有没有一种方法可以实现拔插事件的响应:动态插入部件?或是其它的方法,请大神指点。 展开
用CreateObject方法创建控件,或者把对应的文件打包在同一目录,或者打包进程序里面待使用的时候再动态释放出来,还有两种动态调用的方法可供参考:
(1)VB使用未注册的ActiveX代码
''IDE下可以引用那个dll使用。编译后可以在未注册dll的计算机上正常工作了。
''使用方法:
''Dim pDll As Long ''记录Dll,用来最后完美释放
''Dim Update As Update.Handle ''要实例化的对象
''Set Update = LoadObjectByName(App.Path & "Update.dll", "Handle", pDll) '' New Update.Handle
''If Update Is Nothing Then Exit Sub
''Update.Test ''<--类中的方法
''Set Update = Nothing ''<-----这句不能少,否则会出现意外错误
''UnLoadDll pDll ''<----释放
''模块中:
Option Explicit
Private Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryW" (ByVal lpLibFileName As Long) As Long
Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Long, ByVal lpProcName As String) As Long
Private Declare Function FreeLibrary Lib "kernel32" (ByVal hLibModule As Long) As Long
Private Declare Function CallAsmCode Lib "user32" Alias "CallWindowProcW" (FirstAsmCode As Long, ByVal pA As Long, ByVal pB As Long, ByVal pC As Long, lpD As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private AsmCode(94) As Long
Function LoadObjectByName(ByVal DllPath As String, ByVal ClsName As String, pDll As Long) As Object
Dim pObj As Long, TLIAPP As Object, TLI As Object
Dim CLSID As String, IID As String, IIDName As String
On Error GoTo Err
Set TLIAPP = CreateObject("TLI.TLIApplication")
Set TLI = TLIAPP.TypeLibInfoFromFile(DllPath)
IIDName = "_" & Trim(ClsName)
CLSID = TLI.GetTypeInfo(Trim(ClsName)).GUID
IID = TLI.GetTypeInfo(Trim(IIDName)).GUID
Set LoadObjectByName = LoadObjectByID(DllPath, CLSID, IID, pDll)
Set TLI = Nothing
Err:
End Function
Function LoadObjectByID(ByVal DllPath As String, ByVal CLSID As String, ByVal IID As String, pDll As Long) As Object
Dim pObj As Long
Call InitAsmCode
pObj = CallAsmCode(AsmCode(20), StrPtr(DllPath), StrPtr(CLSID), StrPtr(IID), pDll)
CopyMemory LoadObjectByID, pObj&, 4&
End Function
Function UnLoadDll(pDll As Long) As Long
Call InitAsmCode
UnLoadDll = CallAsmCode(AsmCode(79), pDll, 0, 0, 0)
End Function
Private Sub InitAsmCode()
If AsmCode(4) Then Exit Sub
Dim pDll As Long
pDll = LoadLibrary(StrPtr("kernel32"))
AsmCode(0) = GetProcAddress(pDll, "LoadLibraryW")
AsmCode(1) = GetProcAddress(pDll, "GetProcAddress")
AsmCode(2) = GetProcAddress(pDll, "FreeLibrary")
Call FreeLibrary(pDll)
AsmCode(4) = &H476C6C44
AsmCode(5) = &H6C437465
AsmCode(6) = &H4F737361
AsmCode(7) = &H63656A62
AsmCode(8) = &H4C430074
AsmCode(9) = &H46444953
AsmCode(10) = &H536D6F72
AsmCode(11) = &H6E697274
AsmCode(12) = &H10067
AsmCode(13) = &H0&
AsmCode(14) = &HC00000
AsmCode(15) = &H0&
AsmCode(16) = &H6F4600
AsmCode(17) = &H65006C
AsmCode(18) = &H320033
AsmCode(19) = &H0&
AsmCode(20) = &H83EC8B55 ''创建对象函数入口
AsmCode(21) = &HE853D8C4
AsmCode(22) = &H0&
AsmCode(23) = &H6CEB815B
AsmCode(24) = &H8D100010
AsmCode(25) = &H105293
AsmCode(26) = &H93FF5210
AsmCode(27) = &H10001010
AsmCode(28) = &H32938D50
AsmCode(29) = &H52100010
AsmCode(30) = &H1493FF50
AsmCode(31) = &H8D100010
AsmCode(32) = &H101C93
AsmCode(33) = &HFF028910
AsmCode(34) = &H101893
AsmCode(35) = &H875FF10
AsmCode(36) = &H101093FF
AsmCode(37) = &HC00B1000
AsmCode(38) = &H86840F
AsmCode(39) = &H45890000
AsmCode(40) = &H20938DFC
AsmCode(41) = &H52100010
AsmCode(42) = &H1493FF50
AsmCode(43) = &HB100010
AsmCode(44) = &H506674C0
AsmCode(45) = &H52EC558D
AsmCode(46) = &HFF0C75FF
AsmCode(47) = &H101C93
AsmCode(48) = &H558D5810
AsmCode(49) = &H938D52D8
AsmCode(50) = &H10001042
AsmCode(51) = &HEC558D52
AsmCode(52) = &HBD0FF52
AsmCode(53) = &H8D3E75C0
AsmCode(54) = &HFF52DC55
AsmCode(55) = &H93FF1075
AsmCode(56) = &H1000101C
AsmCode(57) = &HD8558B50
AsmCode(58) = &H8D54128B
AsmCode(59) = &H6A50DC45
AsmCode(60) = &HD875FF00
AsmCode(61) = &HB0C52FF
AsmCode(62) = &H8B1575C0
AsmCode(63) = &H4D8BFC45
AsmCode(64) = &H59018914
AsmCode(65) = &H8BD18B51
AsmCode(66) = &H52FF5112
AsmCode(67) = &H14EB5804
AsmCode(68) = &HEB06EB58
AsmCode(69) = &HEB02EB0F
AsmCode(70) = &HFC75FF0B
AsmCode(71) = &H101893FF
AsmCode(72) = &HC0331000
AsmCode(73) = &H10C2C95B
AsmCode(74) = &H6C6C4400
AsmCode(75) = &H556E6143
AsmCode(76) = &H616F6C6E
AsmCode(77) = &H776F4E64
AsmCode(78) = &H0&
AsmCode(79) = &H53EC8B55 ''尝试卸载DLL函数入口
AsmCode(80) = &HE8&
AsmCode(81) = &HEB815B00
AsmCode(82) = &H10001155
AsmCode(83) = &H1139938D
AsmCode(84) = &HFF521000
AsmCode(85) = &H93FF0875
AsmCode(86) = &H10001014
AsmCode(87) = &H1374C00B
AsmCode(88) = &HC00BD0FF
AsmCode(89) = &H75FF0E74
AsmCode(90) = &H1893FF08
AsmCode(91) = &H33100010
AsmCode(92) = &H4801EBC0
AsmCode(93) = &H10C2C95B
AsmCode(94) = &H90909000
End Sub
(2)vb.net 通过类厂创建com对象的方法
vb.net中要创立com对象可以用new或者CreateObject,就像C++中的CoCreateInstance,一步调用就直接创建了com对象。在它们之中包括了对CoGetClassObject和CreateInstance的调用。默认使用的类厂是IClassFactory。
一般情况下,new或CreateObject已经够用了。但是如果我们的com组件增加了授权,也就是使用了IClassFactory2接口。那么在vb中继续用这种方法就不能创建我们所需要的组件了。我们必须使用IClassFactory2。
在C++中实现很简单。只需要通过CoGetClassObject获得IClassFactory2接口,然后调用它的CreateInstanceLic来创建组件。
因此,在vb.net中,我们就可以仿照c++中的方法。下面是相关代码:
首先声明IClassFactory2的接口。IClassFactory2.idl如下:
[
uuid(6ED6AF97-F279-4d57-A392-0B8ACF89426C),
version(1.0),
helpstring("INVENTOROCIDL Type Library 1.0")
]
library INVENTOROCIDL
{
interface IClassFactory2;
typedef enum enuCLSCTX
{
enuCLSCTX_INPROC_SERVER = 1,
enuCLSCTX_INPROC_HANDLER = 2,
enuCLSCTX_LOCAL_SERVER = 4,
enuCLSCTX_REMOTE_SERVER = 16,
enuCLSCTX_NO_CODE_DOWNLOAD = 400,
enuCLSCTX_NO_FAILURE_LOG = 4000,
enuCLSCTX_SERVER = (1 | 4 | 16),
enuCLSCTX_ALL = (2 | 1)
} CLSCTX;
[
object,
uuid(B196B28F-BAB4-101A-B69C-00AA00341D07),
pointer_default(unique)
]
interface IClassFactory2 : IClassFactory
{
typedef IClassFactory2 * LPCLASSFACTORY2;
typedef struct tagLICINFO {
LONG cbLicInfo;
BOOL fRuntimeKeyAvail;
BOOL fLicVerified;
} LICINFO;
typedef struct tagLICINFO * LPLICINFO;
HRESULT GetLicInfo(
[out, retval] LICINFO * pLicInfo
);
HRESULT RequestLicKey(
[in] LONG dwReserved,
[out, retval] BSTR * pBstrKey
);
[local]
HRESULT CreateInstanceLic(
[in] IUnknown * pUnkOuter,
[in] IUnknown * pUnkReserved,
[in] GUID* riid,
[in] BSTR bstrKey,
[out, retval, iid_is(riid)] PVOID * ppvObj
);
}
}
用midl编译成IClassFactory2.tlb,并导入到vb.net的工程当中。
声明如下api用于得到IClassFactory2接口:
Declare Function CoGetClassObject Lib "ole32.dll" (ByRef rclsid As Guid, ByVal context As Short, ByRef serverInfo As IntPtr, ByRef riid As Guid, ByRef ppv As IntPtr) As Integer
'添加如下代码:
Const bstrInventorApplication As String = "{B6B5DC40-96E3-11d2-B774-0060B0F159EF}"
Const bstrIClassFactory2 As String = "{B196B28F-BAB4-101A-B69C-00AA00341D07}"
Const bstrIDispatch As String = "{00020400-0000-0000-C000-000000000046}"
Private IClsFry2 As INVENTOROCIDL.IClassFactory2
Dim bstrLicence As String = "12345678" 'licence key
Dim guidInventorApplication As Guid = New Guid(bstrInventorApplication)
Dim guidIClassFactory2 As Guid = New Guid(bstrIClassFactory2)
Dim guidIDispatch As Guid = New Guid(bstrIDispatch)
Dim InventorGuid As INVENTOROCIDL.GUID 'used by CreateInstanceLic,defined in INVENTOROCIDL
'transform Guid of IDispatch to INVENTOROCIDL.GUID
Dim byteArry() As Byte = guidIDispatch.ToByteArray()
Dim MyGC As GCHandle = GCHandle.Alloc(byteArry, GCHandleType.Pinned)
InventorGuid = CType(Marshal.PtrToStructure(MyGC.AddrOfPinnedObject, InventorGuid.GetType()), INVENTOROCIDL.GUID)
'get the IClassFactory2 Interface
Dim obj As IntPtr
CoGetClassObject(guidInventorApplication, CInt(INVENTOROCIDL.enuCLSCTX.enuCLSCTX_LOCAL_SERVER), Nothing, guidIClassFactory2, obj)
IClsFry2 = CType(Marshal.GetTypedObjectForIUnknown(obj, System.Type.GetTypeFromCLSID(guidIClassFactory2)), INVENTOROCIDL.IClassFactory2)
'create Inventor Instance by using Licence
obj = IClsFry2.CreateInstanceLic(Nothing, Nothing, InventorGuid, bstrLicence)
InvApp = CType(Marshal.GetTypedObjectForIUnknown(obj, System.Type.GetTypeFromCLSID(guidInventorApplication)), Inventor.Application)
致此创建成功!