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我想將以下兩個接口從C頭文件轉換爲Delphi PAS單元，但在使用我自己做的那些時遇到了奇怪的問題。我需要幫助瞭解如何在Delphi中實現這些。從C頭文件將COM對象接口從C轉換爲Delphi
來源接口：
interface IParamConfig: IUnknown
{
HRESULT SetValue([in] const VARIANT* pValue, [in] BOOL bSetAndCommit);
HRESULT GetValue([out] VARIANT* pValue, [in] BOOL bGetCommitted);
HRESULT SetVisible(BOOL bVisible);
HRESULT GetVisible(BOOL* bVisible);
HRESULT GetParamID(GUID* pParamID);
HRESULT GetName([out] BSTR* pName);
HRESULT GetReadOnly(BOOL* bReadOnly);
HRESULT GetFullInfo([out] VARIANT* pValue, [out] BSTR* pMeaning, [out] BSTR* pName, [out] BOOL* bReadOnly, [out] BOOL* pVisible);
HRESULT GetDefValue([out] VARIANT* pValue);
HRESULT GetValidRange([out] VARIANT* pMinValue, [out] VARIANT* pMaxValue, [out] VARIANT* pDelta);
HRESULT EnumValidValues([in][out] long* pNumValidValues, [in][out] VARIANT* pValidValues,[in][out] BSTR* pValueNames);
HRESULT ValueToMeaning([in] const VARIANT* pValue, [out] BSTR* pMeaning);
HRESULT MeaningToValue([in] const BSTR pMeaning, [out] VARIANT* pValue);
}
interface IModuleConfig: IPersistStream
{
HRESULT SetValue([in] const GUID* pParamID, [in] const VARIANT* pValue);
HRESULT GetValue([in] const GUID* pParamID, [out] VARIANT* pValue);
HRESULT GetParamConfig([in] const GUID* pParamID, [out] IParamConfig** pValue);
HRESULT IsSupported([in] const GUID* pParamID);
HRESULT SetDefState();
HRESULT EnumParams([in][out] long* pNumParams, [in][out] GUID* pParamIDs);
HRESULT CommitChanges([out] VARIANT* pReason);
HRESULT DeclineChanges();
HRESULT SaveToRegistry([in] HKEY hKeyRoot, [in] const BSTR pszKeyName, [in] const BOOL bPreferReadable);
HRESULT LoadFromRegistry([in] HKEY hKeyRoot, [in] const BSTR pszKeyName, [in] const BOOL bPreferReadable);
HRESULT RegisterForNotifies([in] IModuleCallback* pModuleCallback);
HRESULT UnregisterFromNotifies([in] IModuleCallback* pModuleCallback);
}
這是我的「盡力而爲」到目前爲止：
type
TWideStringArray = array[0..1024] of WideString;
TOleVariantArray = array[0..1024] of OleVariant;
TGUIDArray = array[0..1024] of TGUID;
IParamConfig = interface(IUnknown)
['{486F726E-5043-49B9-8A0C-C22A2B0524E8}']
function SetValue(const pValue: OleVariant; bSetAndCommit: BOOL): HRESULT; stdcall;
function GetValue(out pValue: OleVariant; bGetCommitted: BOOL): HRESULT; stdcall;
function SetVisible(bVisible: BOOL): HRESULT; stdcall;
function GetVisible(bVisible: BOOL): HRESULT; stdcall;
function GetParamID(pParamID: PGUID): HRESULT; stdcall;
function GetName(out pName: WideString): HRESULT; stdcall;
function GetReadOnly(bReadOnly: BOOL): HRESULT; stdcall;
function GetFullInfo(out pValue: OleVariant; out pMeaning: WideString; out pName: WideString; out pReadOnly: BOOL; out pVisible: BOOL): HRESULT; stdcall;
function GetDefValue(out pValue: OleVariant): HRESULT; stdcall;
function GetValidRange(out pMinValue: OleVariant; out pMaxValue: OleVariant; out pDelta: OleVariant): HRESULT; stdcall;
function EnumValidValues(var pNumValidValues: Integer; var pValidValues: TOleVariantArray; var pValueNames: TWideStringArray): HRESULT; stdcall;
function ValueToMeading(const pValue: OleVariant; out pMeaning: WideString): HRESULT; stdcall;
function MeaningToValue(const pMeaning: WideString; out pValue: OleVariant): HRESULT; stdcall;
end;
IModuleConfig = interface(IPersistStream)
['{486F726E-4D43-49B9-8A0C-C22A2B0524E8}']
function SetValue(const pParamID: TGUID; const pValue: OleVariant): HRESULT; stdcall;
function GetValue(const pParamID: TGUID; out pValue: OleVariant): HRESULT; stdcall;
function GetParamConfig(const ParamID: TGUID; out pValue: IParamConfig): HRESULT; stdcall;
function IsSupported(const pParamID: TGUID): HRESULT; stdcall;
function SetDefState: HRESULT; stdcall;
function EnumParams(var pNumParams: Integer; var pParamIDs: TGUIDArray): HRESULT; stdcall;
function CommitChanges(out pReason: OleVariant): HRESULT; stdcall;
function DeclineChanges: HRESULT; stdcall;
function SaveToRegistry(hKeyRoot: HKEY; const pszKeyName: WideString; const bPreferReadable: BOOL): HRESULT; stdcall;
function LoadFromRegistry(hKeyRoot: HKEY; const pszKeyName: WideString; const bPreferReadable: BOOL): HRESULT; stdcall;
function RegisterForNotifies(pModuleCallback: IModuleCallback): HRESULT; stdcall;
function UnregisterFromNotifies(pModuleCallback: IModuleCallback): HRESULT; stdcall;
end;
下面是使用DirectShow過濾器，並試圖同時使用一些示例代碼該對象上的IModuleConfig和IParamConfig接口：
procedure TForm10.Button1Click(Sender: TObject);
const
CLSID_VideoDecoder: TGUID = '{C274FA78-1F05-4EBB-85A7-F89363B9B3EA}';
var
HR: HRESULT;
Intf: IUnknown;
NumParams: Long;
I: Integer;
ParamConfig: IParamConfig;
ParamName: WideString;
Value: OleVariant;
ValAsString: String;
Params: TGUIDArray;
begin
CoInitializeEx(nil, COINIT_MULTITHREADED);
try
HR := CoCreateInstance(CLSID_VideoDecoder, nil, CLSCTX_INPROC_SERVER or CLSCTX_LOCAL_SERVER, IUnknown, Intf);
if Succeeded(HR) then
begin
FVideoDecoder := Intf as IBaseFilter;
if Supports(FVideoDecoder, IID_IModuleConfig) then
begin
HR := (FVideoDecoder as IModuleConfig).EnumParams(NumParams, Params);
if HR = S_OK then
begin
for I := 0 to NumParams - 1 do
begin
HR := (FVideoDecoder as IModuleConfig).GetParamConfig(Params[I], ParamConfig);
if HR = S_OK then
begin
try
ParamConfig.GetName(ParamName);
ParamConfig.GetValue(Value, True);
try
ValAsString := VarToStrDef(Value, 'Error');
SL.Add(String(ParamName) + '=' + String(ValAsString)); // <-- ADDING THIS LINE WILL ALWAYS MAKE EnumParams call return S_FALSE = 1
except
end;
finally
ParamConfig := nil;
end;
end;
end;
end;
end;
end;
finally
CoUninitialize;
end;
end;
使用調試器I可以看到示例代碼都檢索到ParamName和Value變量的數據，但是，當我嘗試將代碼存儲到字符串列表（SL）時，對EnumParams的調用將始終返回S_FALSE（1）而不是S_OK（0）。如果我註釋掉SL.Add（...）和RECOMPILE行，它將再次起作用。如果我再次包含它，並且RECOMPILE它不會。這讓我相信，由於我錯誤地實現了這些接口，某些事情正在搞亂內存，並且包含額外的代碼使得它發生。
我非常確定我分配給變量的類型在某種程度上是這個的罪魁禍首，尤其是EnumParams的第二個參數，它應該返回一個GUID *數組。我也很不確定IParamConfig.EnumValidValues調用是否也返回值的數組。
我正在使用Delphi XE2。
在這個問題上的任何幫助是非常appreaciated。
謝謝大衛！使用您發佈的信息，我確實設法正確地實現了界面。我有這個對象的文檔，但不幸的是它的版權，所以我不能在這裏發佈。 – TomRay74 2012-03-18 16:47:39
很高興能幫助 – 2012-03-18 16:52:39