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  4. _variant_t to CString

_variant_t to CString

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  • R rdop

    Hi All How can i convert _variant_t to CString?

    L Offline
    L Offline
    Lost User
    wrote on last edited by
    #7

    Hi rdop, The following snippit will work on all Microsoft compilers:_variant_t v; v = 3.141; ::VariantChangeType(&v, &v, 0, VT_BSTR); CString s = (LPTSTR)(_bstr_t)v.bstrVal;
    Best Wishes, -David Delaune

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    • R rdop

      Plz help me some one

      S Offline
      S Offline
      Stuart Dootson
      wrote on last edited by
      #8

      I (and Microsoft, who wrote the _variant_t and CString code) have helped you - you just assign the _variant_t to the CString - what more do you want?!?!?!?!?

      Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

      R 1 Reply Last reply
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      • S Stuart Dootson

        Noooooo - you don't need to bother with that - there's a VariantChangeType function that'll do that for you when you convert a VARIANT to a BSTR. And even more conveniently, the combination of _variant_t extractor operators and CString constructors will do all that for you. A simple assignment of _variant_t to CString is all that's needed...

        Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

        C Offline
        C Offline
        CPallini
        wrote on last edited by
        #9

        Nice to know :thumbsup:. What about _variant_t containing arrays? :)

        If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
        This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
        [My articles]

        S 1 Reply Last reply
        0
        • S Stuart Dootson

          I (and Microsoft, who wrote the _variant_t and CString code) have helped you - you just assign the _variant_t to the CString - what more do you want?!?!?!?!?

          Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

          R Offline
          R Offline
          rdop
          wrote on last edited by
          #10

          See what happen.

          _variant_t vtValue;
          vtValue = m_pRset->Fields->GetItem("Bianry")->GetValue();
          CString b=vtValue;
          output is b = "??4"
          when i copy the vtValues at the time of debug then i got values
          safearray of UI1 = [20](54 '6',53 '5',52 '4',54 '6',52 '4',0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)

          Any more information if you nedd then i will give you.

          S 1 Reply Last reply
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          • R rdop

            Thanks for responce.I hava a biray type data in _variant_t. _variant_t v1; v1=(54 '6',53 '5',52 '4',54 '6',52 '4',0,0,0,0,0,0,0,0,0,0,0,0,0,0,0); Can i convert these values in CString or not. Origal values is"65464". Plz help me

            C Offline
            C Offline
            CPallini
            wrote on last edited by
            #11

            What is v1.vt value? :)

            If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
            This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
            [My articles]

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            • R rdop

              See what happen.

              _variant_t vtValue;
              vtValue = m_pRset->Fields->GetItem("Bianry")->GetValue();
              CString b=vtValue;
              output is b = "??4"
              when i copy the vtValues at the time of debug then i got values
              safearray of UI1 = [20](54 '6',53 '5',52 '4',54 '6',52 '4',0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)

              Any more information if you nedd then i will give you.

              S Offline
              S Offline
              Stuart Dootson
              wrote on last edited by
              #12

              As it's an array, VariantChangeType's not going to work. So, I'd suggest the code below. I'm assuming you want to access the non-null characters of the array and make them into a string?

              CComSafeArray<char, VT_UI1> sa(V_ARRAY(&v));
              CString s;
              for(int index=sa.GetLowerBound();index<=sa.GetUpperBound()&&sa[index];++index)
              {
              s+=sa[index];
              }

              [edit] You'll also need to #include atlsafe.h and oleauto.h [/edit]

              Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

              L R 2 Replies Last reply
              0
              • C CPallini

                Nice to know :thumbsup:. What about _variant_t containing arrays? :)

                If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                [My articles]

                S Offline
                S Offline
                Stuart Dootson
                wrote on last edited by
                #13

                CPallini wrote:

                What about _variant_t containing arrays?

                Use CComSafeArray[^].

                _variant_t v;
                // Assign a SAFEARRAY value to v
                CComSafeArray<char, VT_UI1> sa(V_ARRAY(&v));
                // Now we can access the SAFEARRAY using sa.

                Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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                • S Stuart Dootson

                  As it's an array, VariantChangeType's not going to work. So, I'd suggest the code below. I'm assuming you want to access the non-null characters of the array and make them into a string?

                  CComSafeArray<char, VT_UI1> sa(V_ARRAY(&v));
                  CString s;
                  for(int index=sa.GetLowerBound();index<=sa.GetUpperBound()&&sa[index];++index)
                  {
                  s+=sa[index];
                  }

                  [edit] You'll also need to #include atlsafe.h and oleauto.h [/edit]

                  Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

                  L Offline
                  L Offline
                  Lost User
                  wrote on last edited by
                  #14

                  Hi Stuart, What do you think about this VT_UI1 SAFEARRAY to CStringA conversion method?BSTR b; BstrFromVector(pSA,&b); CStringA s = (LPCSTR)b;
                  Best Wishes, -David Delaune

                  S 1 Reply Last reply
                  0
                  • L Lost User

                    Hi Stuart, What do you think about this VT_UI1 SAFEARRAY to CStringA conversion method?BSTR b; BstrFromVector(pSA,&b); CStringA s = (LPCSTR)b;
                    Best Wishes, -David Delaune

                    S Offline
                    S Offline
                    Stuart Dootson
                    wrote on last edited by
                    #15

                    New to me - that'll teach me to do what I've told many other people to do and read the documentation :laugh: And of course it'll work with wide CStrings as well.

                    Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

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                    0
                    • S Stuart Dootson

                      As it's an array, VariantChangeType's not going to work. So, I'd suggest the code below. I'm assuming you want to access the non-null characters of the array and make them into a string?

                      CComSafeArray<char, VT_UI1> sa(V_ARRAY(&v));
                      CString s;
                      for(int index=sa.GetLowerBound();index<=sa.GetUpperBound()&&sa[index];++index)
                      {
                      s+=sa[index];
                      }

                      [edit] You'll also need to #include atlsafe.h and oleauto.h [/edit]

                      Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

                      R Offline
                      R Offline
                      rdop
                      wrote on last edited by
                      #16

                      thanks it's working for me.

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