MANAGE c++ System::Convert::ToDouble with TCHAR ARRAY

Linh Huynh 96

Hi,
I try convert TCHAR tcValues to double using the function below.

I use Manage C ++:

TCHAR tcValue[100] ;

//assume that tcValue = "0.1234" ;

                dblValue = System::Convert::ToDouble (tcValue) ;  // I always got dblValue = 1.0 for any value in tcValue
                dblValue = System::Convert::ToDouble (gcnew String(tcValue)) ; //I got correct value store in tcValue

My question is why this function (System::Convert::ToDouble (tcValue))
does not generate any error but does not return correct value stored in tcValue

Is this a bug in this System::Convert::ToDouble function?

Thanks

David Lowndes 4,721 Reputation points

2021-02-01T14:37:14.663+00:00

I think you're seeing a quirk - it appears to be calling the ToDouble( Boolean ) overload in that case.
Linh Huynh 96 Reputation points

2021-02-01T14:56:24.647+00:00

Thanks for replying to my question

Is that a bug in this overload that it would treat an array of TCHAR as boolean.

If it is then I would need to report to MS.

I
David Lowndes 4,721 Reputation points

2021-02-01T15:51:34.76+00:00
I don't understand why it's picking the Boolean overload in that situation, particularly when other similar ones work. For example, a String object is created from the literal in this case:

double dv1 = System::Convert::ToDouble( "0.1234" );

As to whether it's a bug, or just a quirk, I don't know, perhaps someone else more versed in that aspect could comment.

If you don't get a definitive answer in a few days, certainly consider reporting it to MS to see what they have to say about it - post a link to any bug report back here so we can follow up on it.

Accepted answer

Linh Huynh 96 Reputation points

2021-02-01T18:05:51.477+00:00

I confirmed that this is a MS bug with .NET Framework 4.0.

I checked my old version and I did have the same code but with .NET Framework 1.1 and it is working correctly.

Thanks
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David Lowndes 4,721 Reputation points

2021-02-01T19:42:56.867+00:00

Are you using the exact same compiler & settings?

Linh Huynh 96 Reputation points

2021-02-01T20:24:36.783+00:00

there are many changes from Managed C++ with .NET 1.1 to .NET 4.0 but my code for this conversion does not change at all.

I could not find where I can report this to MS to see what they think about this scenario

David Lowndes 4,721 Reputation points

2021-02-01T20:26:37.72+00:00

Use Help, Send Feedback, Report a Problem (in the latest VS 2019)
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