VARIANT PARRAY

VARIANT PARRAY

• Edwin Jongsma

  I am not sure, but I think that VB is passing the value as "by reference" were as C# is passing the value "by value".
  
  I think it doesn't matter how you get the data. You can see it in the variant type, what you get. BTW: Can you tell us the type flags given in the type field of the VARIANT.
  
  AFAIK it depends also how you call the method from VB.
  
  method(array) ' passes the array by value
  method array ' passes the array by reference
  
  Just read the KB article
  Q142223 http://support.microsoft.com/kb/142223/en-us
  
  HTH
  
  

• GaltSalt

  Hi,
  Many thanks for your replies.
  
  Here is what i do,
  
  vbmethod
  
  Public Declare Function PassArraySample Lib "C:\MyWork\APPLICATIONS\TestSamples\Test1\Debug\Test1.dll" (ByVal Ser As String, ByVal Sym As String, ByRef varArray As Variant) As Integer
  
  lReturn = PassArraySample("a", "b", varray)
  
  
  c# ofcoure works fine.
  
  anyideas. Thanks  vi
  
  

• softwarejaeger

  Many thanks Martin,
  
  I tried the last parameter in the vb func as byvalue and I get the following error:
  
  "Unhandled exception in exe(Test1.dll):0xC0000005: Access Violation"
  
  Any ideas please
  
  fyi, when I pass the last parameter Byref I dont get any error but Array is assigned to pparray of the variant , but I want that to be assigned to parray of the variant.
  
  c++ method signature
  ---------------------
  
  long __declspec(dllexport) __stdcall PassArraySample( const char*  szSer, const  *szSym, VARIANT &pVariantArray)
  
  SAFEARRAY * pArrayVal = pVariantArray.parray;
  VARIANT *pArray = NULL;
  HRESULT hr = S_OK;
  long lRet = -1;

  hr = SafeArrayAccessData(pArrayVal, (void HUGEP * FAR *) &pArray);
  ........
  _______________________________________ 
  
  vb method
  
  Public Declare Function PassArraySample Lib "C:\MyWork\APPLICATIONS\TestSamples\Test1\Debug\Test1.dll" (ByVal Ser As String, ByVal Sym As String, ByVal varArray As Variant) As Integer

  best reg. Vi

  
  

• derek73

   

  Hi,

  I have a c++ method that accepts variant array as a parameter.

  when I pass the variant array from  c# client , the value is assigned to Variant.parray in c++ method but when pass the variant from vb client the value is assigned to Variant.pparray. I want vb to assign value to Variant.parray and not pparray,what do I do, any ideas please.

  Many thanks in advance.

  vi
  

  
  
  

• integrators

  Declare the last parameter in the VB function as by value!
  
  
• VARIANT PARRAY