在 Office 中使用存储在 CustomXMLPart 中的 base64 数据作为图像 [英] Using base64 data stored in CustomXMLPart as image in Office

问题描述

作为这个问题的后续，关于在功能区的按钮上使用存储在 Excel 文件中的图像:>

是否可以使用 base64 编码字符串中存储在 CustomXMLPart/CustomXMLNode 中的图像作为 Office 文档中的图像，而无需先将其保存到磁盘并重新加载?

我想使用图像的地方需要一个 IPictureDisp 对象作为参数(就像 LoadPicture 函数返回一样，但它只会从磁盘加载文件).

解决方案

首先需要将 base_64 数据转换为字节数组:

私有函数decodeBase64(ByVal strData As String) As Byte()Dim objXML As MSXML2.DOMDocumentDim objNode 作为 MSXML2.IXMLDOMElement设置 objXML = 新建 MSXML2.DOMDocument设置 objNode = objXML.createElement("b64")objNode.DataType = "bin.base64"objNode.Text = strDatadecodeBase64 = objNode.nodeTypedValue设置 objNode = 无设置 objXML = 无结束函数

来自:http://thydzik.com/vb6vba-functions-to-convert-binary-string-to-base64-string/

然后您可以将其加载到内存中并使用有关此主题的信息创建您的 IPictureDisp:http://www.xtremevbtalk.com/showthread.php?t=137857

输入 GUID数据1只要Data2 作为整数Data3 作为整数Data4(7) 作为字节结束类型私有声明函数 CreateStreamOnHGlobal Lib "ole32.dll" (ByRef hGlobal As Any, ByVal fDeleteOnResume As Long, ByRef ppstr As Any) As Long私有声明函数 OleLoadPicture Lib "olepro32.dll" (ByVal lpStream As IUnknown, ByVal lSize As Long, ByVal fRunMode As Long, ByRef riid As GUID, ByRef lplpObj As Any) As Long私有声明函数 CLSIDFromString Lib "ole32.dll" (ByVal lpsz As Long, ByRef pclsid As GUID) As LongPrivate Const SIPICTURE As String = "{7BF80980-BF32-101A-8BBB-00AA00300CAB}"公共函数 PictureFromArray(ByRef b() As Byte) As IPicture出错时转到错误处理程序Dim istrm As IUnknownDim tGuid 作为 GUID如果不是 CreateStreamOnHGlobal(b(LBound(b)), False, istrm) 然后CLSIDFromString StrPtr(SIPICTURE), tGuidOleLoadPicture istrm, UBound(b) - LBound(b) + 1, False, tGuid, PictureFromArray万一设置 istrm = 无退出函数错误处理程序:Debug.Print 无法转换为 IPicture！"结束函数

As a followup to this question about using images stored in an Excel file on a button in the ribbon:

Is it possible to use an image stored in a CustomXMLPart/CustomXMLNode in base64-encoded string as an image in an Office document without first saving it to disk and loading it back?

The place where I want to use the image takes an IPictureDisp object as a parameter (like the LoadPicture function returns, but that will only load files from disk).

解决方案

First you need to convert your base_64 data to byte array:

Private Function decodeBase64(ByVal strData As String) As Byte()
    Dim objXML As MSXML2.DOMDocument
    Dim objNode As MSXML2.IXMLDOMElement

    Set objXML = New MSXML2.DOMDocument
    Set objNode = objXML.createElement("b64")
    objNode.DataType = "bin.base64"
    objNode.Text = strData
    decodeBase64 = objNode.nodeTypedValue

    Set objNode = Nothing
    Set objXML = Nothing
End Function

from: http://thydzik.com/vb6vba-functions-to-convert-binary-string-to-base64-string/

then you can load it in memory and create your IPictureDisp using information on this topic: http://www.xtremevbtalk.com/showthread.php?t=137857

Type GUID
  Data1 As Long
  Data2 As Integer
  Data3 As Integer
  Data4(7) As Byte
End Type

Private Declare Function CreateStreamOnHGlobal Lib "ole32.dll" (ByRef hGlobal As Any,     ByVal fDeleteOnResume As Long, ByRef ppstr As Any) As Long
Private Declare Function OleLoadPicture Lib "olepro32.dll" (ByVal lpStream As IUnknown, ByVal lSize As Long, ByVal fRunMode As Long, ByRef riid As GUID, ByRef lplpObj As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32.dll" (ByVal lpsz As Long, ByRef pclsid As GUID) As Long

Private Const SIPICTURE As String = "{7BF80980-BF32-101A-8BBB-00AA00300CAB}"

Public Function PictureFromArray(ByRef b() As Byte) As IPicture
  On Error GoTo errorhandler

  Dim istrm As IUnknown
  Dim tGuid As GUID

  If Not CreateStreamOnHGlobal(b(LBound(b)), False, istrm) Then
    CLSIDFromString StrPtr(SIPICTURE), tGuid
    OleLoadPicture istrm, UBound(b) - LBound(b) + 1, False, tGuid, PictureFromArray
  End If

  Set istrm = Nothing
  Exit Function
errorhandler:
  Debug.Print "Could not convert to IPicture!"
End Function

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