using VARIANT or converting to CString

I'v been searching the whole Internet for the following problem :

how to convert a CString to a Variant

my problem :
I'm working on an ADO database and I want to use the filter of the _recordsetPtr
like this :

_RecordsetPtr m_pRS ;
CString strFilter = "Name LIKE 'a*'" ;

m_pRS.Filter = strFilter ;

only problem : the Filter only takes a variant :(

or maybe can someone explain to me how I must use the VARIANT type?
I already searched MSDN and the web, but nowhere any good explanation on VARIANT :(

TIA

Quote:

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Originally Posted by da_cobra

how to convert a CString to a Variant

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CString to VARIANT Conversion: Method I

Code:

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  // Your CString
    CString strInput (_T ("Test String"));
 
    VARIANT varString;
 
    // Create a BSTR, assign it.
    varString.bstrVal = strInput.AllocSysString ();
 
    // Set Variant Type
    varString.vt = VT_BSTR;
 
    // Use the VARIANT
 
    // De-Allocate it: Don't forget this step if you are using Raw Variants
    ::VariantClear (&varString);

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CString to VARIANT Conversion: Method II

Code:

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  // Using the CComVariant: Smart Wrapper Class for VARIANT
        CComVariant varSmartVariantString (strInput);
 
    // Use varSmartVariantString...

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Quote:

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Originally Posted by da_cobra

or maybe can someone explain to me how I must use the VARIANT type?

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Q. What is a VARIANT?
A. A VARIANT is a structure.

Code:

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typedef struct tagVARIANT VARIANT;
  typedef struct tagVARIANT VARIANTARG;
  struct tagVARIANT
  {
    // ... variant members...
  };

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It can support many data-types because it (the structure) contains a UNION as a member.
The Variant Type is identified by the member VARIANT::vt

Quote:

---

Originally Posted by da_cobra

I already searched MSDN and the web, but nowhere any good explanation on VARIANT

---

The link above contains detailed information.

Let me know if your query is solved.

thx alot! this really helped me!!!

You are welcome.

Ciao,
Sid! :thumb: