Troubles with UnicodeString

Detlef Meyer-Eltz

I'm new to the LMD components and I'm confused about UnicodeStrings. I had troubles to insert an UnicodeString into a cell of a grid.

Grid->Cells[PathCol->Position][i] = L"testpath";

produced some additonal garbage characters. Then I found the following link:

http://wiki.lmd.de/index.php/LMD_VCL_-_Unicode_Support

Do I really have to use LMDUnicodeStrings? If yes, then please give me a code snippet, how to convert beween Delphi UnicodeString and LMDUnicodeStrings and back. Or do I have to recompile the packages with special definitions. At the moment I'm working with the lib files that were installed with setupvcl17d25.exe. I'm using C++Builder 10.2 Tokyo.

Detlef Meyer-Eltz

I should make my error example more clear: the grid component, that I used was a TLMDGrid. I expected that there were a function to insert a new row. Because there is no, I tried to create my own. The following worked well:

void xxx::AddRow()
{
 int i = gv_Sources->DataRowCount;
 Grid->DataRowCount++;
 Grid->Cells[IncrCol->Position][i] = i;
 Grid->Cells[PathCol->Position][i] = "testpath";
  ...
 
 
But as soon as I changed "testpath" to L"testpath", I got a lot of troubles.

Detlef Meyer-Eltz

P.S.: there is no DataSource. The gid shall work in Memory.

Eugene Balabuev (LMD)

C++ prefix L represents wide-character strings, not UnicodeStrings. Please read:

http://docwiki.embarcadero.com/RADStudio/Tokyo/de/String-Typen_(Delphi) or

http://docwiki.embarcadero.com/RADStudio/Tokyo/de/Unicode_in_RAD_Studio

Since Delphi/C++Builder 2009 standard string type is UnicodeString (which is supported by TLMDGrid as default conversion from/to Variant data type).

 

If you need explicitely WideString support, write your own custom datasource (small example is in Grid demo included, can be certainly in-memory as well).

Rafael Maricca (LMD)

C++ prefix L represents wide-character strings (UTF-16), not UnicodeString (UTF-8). Please read:

http://docwiki.embarcadero.com/RADStudio/Tokyo/de/Unicode_in_RAD_Studio

Since Delphi/C++Builder 2009 standard VCL string type is UnicodeString (which is supported by TLMDGrid as default conversion from/to internal Variant data type in text columns). So if your string data is in UTF-16 format, make sure to convert it beforehand.

LMD Code can be recompiled to support WideStrings natively (see lmdcmps.inc compiler switches for options, that's the way Unicode was supported before VCL Unicode support in Delphi/C++Builder 2009+), but this not something we advise or test for new compilers and which is certainly slower than the built-in Unicode string.

Detlef Meyer-Eltz

Of course, I like to use UnicodeStrings. It was your wike page, that confused me:

http://wiki.lmd.de/index.php/LMD_VCL_-_Unicode_Support

and in addition my whole IDE crashed, when I was degugging the code. Therefore I couldn't continue my experiments.

Now I have reinstalled everything and the following works:

Grid->Cells[PathCol->Position][i] = UnicodeString(L"testpath");

or simply

Grid->Cells[PathCol->Position][i] = String(L"testpath");

BTW: wchar_t arrays can be assigned as well to WideString's as to UnicodeString's.

 WideString ws = L"testpath";
 UnicodeString s = L"testpath";

Because my PathCol is a TLMDGridTextColumn, I assumed that the correct constructor would be invoked automatically.

Thank you!