通过

PWINBIO_CAPTURE_CALLBACK回调函数 (winbio.h)

  • 项目

由 Windows 生物识别框架调用，以从异步 WinBioCaptureSampleWithCallback 函数返回结果。 客户端应用程序必须实现此函数。

重要建议从 Windows 8 开始，不再使用 PWINBIO_CAPTURE_CALLBACK/WinBioCaptureSampleWithCallback 组合。 请改为执行以下操作：
 

语法

PWINBIO_CAPTURE_CALLBACK PwinbioCaptureCallback;

void PwinbioCaptureCallback(
  [in, optional] PVOID CaptureCallbackContext,
  [in]           HRESULT OperationStatus,
  [in]           WINBIO_UNIT_ID UnitId,
  [in]           PWINBIO_BIR Sample,
  [in]           SIZE_T SampleSize,
  [in]           WINBIO_REJECT_DETAIL RejectDetail
)
{...}

参数

[in, optional] CaptureCallbackContext

指向由应用程序定义并传递给 WinBioCaptureSampleWithCallback 函数的 CaptureCallbackContext 参数的缓冲区的指针。 该缓冲区不会由框架或生物识别单元修改。 应用程序可以使用数据来帮助它确定要执行的操作或维护有关生物识别捕获的其他信息。

[in] OperationStatus

捕获操作返回的错误代码。

[in] UnitId

生物识别单元 ID 号。

[in] Sample

指向示例数据的指针。

[in] SampleSize

Sample 参数指向的示例数据的大小（以字节 为单位 ）。

[in] RejectDetail

有关执行操作失败（如果有）的其他信息。 有关详细信息，请参阅“备注”。

返回值

无

备注

目前，Windows 生物识别框架仅支持指纹读取器。 因此，如果操作失败并在 WINBIO_REJECT_DETAIL 常量中返回其他信息，则它将是以下值之一：

  • WINBIO_FP_TOO_HIGH
  • WINBIO_FP_TOO_LOW
  • WINBIO_FP_TOO_LEFT
  • WINBIO_FP_TOO_RIGHT
  • WINBIO_FP_TOO_FAST
  • WINBIO_FP_TOO_SLOW
  • WINBIO_FP_POOR_QUALITY
  • WINBIO_FP_TOO_SKEWED
  • WINBIO_FP_TOO_SHORT
  • WINBIO_FP_MERGE_FAILURE

示例

下面的代码示例通过调用 WinBioCaptureSampleWithCallback 并将指针传递给自定义回调函数 CaptureSampleCallback 来异步捕获示例。 链接到 Winbio.lib 静态库并包含以下头文件：

  • Windows.h
  • Stdio.h
  • Conio.h
  • Winbio.h
HRESULT CaptureSampleWithCallback(BOOL bCancel)
{
    HRESULT hr = S_OK;
    WINBIO_SESSION_HANDLE sessionHandle = NULL;

    // Connect to the system pool. 
    hr = WinBioOpenSession( 
            WINBIO_TYPE_FINGERPRINT,    // Service provider
            WINBIO_POOL_SYSTEM,         // Pool type
            WINBIO_FLAG_RAW,            // Raw access
            NULL,                       // Array of biometric unit IDs
            0,                          // Count of biometric unit IDs
            WINBIO_DB_DEFAULT,          // Default database
            &sessionHandle              // [out] Session handle
            );
    if (FAILED(hr))
    {
        wprintf_s(L"\n WinBioOpenSession failed. hr = 0x%x\n", hr);
        goto e_Exit;
    }

    // Capture a biometric sample asynchronously.
    wprintf_s(L"\n Calling WinBioCaptureSampleWithCallback ");
    hr = WinBioCaptureSampleWithCallback(
            sessionHandle,                  // Open session handle
            WINBIO_NO_PURPOSE_AVAILABLE,    // Intended use of the sample
            WINBIO_DATA_FLAG_RAW,           // Sample format
            CaptureSampleCallback,          // Callback function
            NULL                            // Optional context
            );
    if (FAILED(hr))
    {
        wprintf_s(L"\n WinBioCaptureSampleWithCallback failed. ");
        wprintf_s(L"hr = 0x%x\n", hr);
        goto e_Exit;
    }
    wprintf_s(L"\n Swipe the sensor ...\n");

    // Cancel the capture process if the bCancel flag is set.
    if (bCancel)
    {
        wprintf_s(L"\n Starting CANCEL timer...");
        Sleep( 7000 );

        wprintf_s(L"\n Calling WinBioCancel\n");
        hr = WinBioCancel( sessionHandle );
        if (FAILED(hr))
        {
            wprintf_s(L"\n WinBioCancel failed. hr = 0x%x\n", hr);
            goto e_Exit;
        }
    }

    // Wait for the asynchronous capture process to complete 
    // or be canceled.
    hr = WinBioWait( sessionHandle );
    if (FAILED(hr))
    {
        wprintf_s(L"\n WinBioWait failed. hr = 0x%x\n", hr);
    }

e_Exit:

    if (sessionHandle != NULL)
    {
        WinBioCloseSession(sessionHandle);
        sessionHandle = NULL;
    }

    wprintf_s(L"\n Press any key to exit...");
    _getch();

    return hr;
}

//------------------------------------------------------------------------
// The following function is the callback for WinBioCaptureSampleWithCallback.
// The function filters the response from the biometric subsystem and 
// writes a result to the console window.
//
VOID CALLBACK CaptureSampleCallback(
    __in_opt PVOID CaptureCallbackContext,
    __in HRESULT OperationStatus,
    __in WINBIO_UNIT_ID UnitId,
    __in_bcount(SampleSize) PWINBIO_BIR Sample,
    __in SIZE_T SampleSize,
    __in WINBIO_REJECT_DETAIL RejectDetail
    )
{
    UNREFERENCED_PARAMETER(CaptureCallbackContext);

    wprintf_s(L"\n CaptureSampleCallback executing");
    wprintf_s(L"\n Swipe processed - Unit ID: %d", UnitId);

    if (FAILED(OperationStatus))
    {
        if (OperationStatus == WINBIO_E_BAD_CAPTURE)
        {
            wprintf_s(L"\n Bad capture; reason: %d\n", RejectDetail);
         }
        else
        {
            wprintf_s(L"\n WinBioCaptureSampleWithCallback failed. ");
            wprintf_s(L" OperationStatus = 0x%x\n", OperationStatus);
        }
        goto e_Exit;
    }

    wprintf_s(L"\n Captured %d bytes.\n", SampleSize);

e_Exit:

    if (Sample != NULL)
    {
        WinBioFree(Sample);
        Sample = NULL;
    }
}

要求

要求 值
最低受支持的客户端 Windows 7 [仅限桌面应用]
最低受支持的服务器 Windows Server 2008 R2 [仅限桌面应用]
目标平台 Windows
标头 winbio.h

另请参阅

WINBIO_REJECT_DETAIL常量

WinBioCaptureSampleWithCallback