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Tommi Prami

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Posts posted by Tommi Prami

  2. Posted

    5 hours ago, Remy Lebeau said:

    By definition, a TryXXX() function does not raise an exception into user code.  TryISO8601ToDate() is no different.

     

    No it does not, that is OK, but debugger breaks to it anyhow, as it raised in the TryISO8601ToDate, and that is kind of exception I would not like to ignore. IF it would be TryISO8601ToDateException then yes. But generalm date conversion exception I would like to raise my attention.

     

    -tee- 

  4. Posted · Edited by Tommi Prami

    Yellow,

     

    Seems that Delphis own routines are bit flaky. There has been bugs over years. Last problem I had was that TryISO8601ToDate will raise exception on string it can't parse. Will handle/eat the exception but not most optimal solution I think.

     

    By good,m I mean that handle nicely error cases, maybe has more options that Delphi version. Obviously very well tested. If also fast, I wouldn't complain.


    -Tee-

  5. Posted

    On 4/12/2024 at 5:53 PM, Stefan Glienke said:

    TValue has no implicit casting rule for integer -> enum - thus it raises the invalid cast exception because you are passing an Integer to SetValue which gets implicit put into a TValue which gets transported further. It later does a type/cast check against the actual type of the property and fails.

    See TValue.Cast or TValue.TryCast and the Conversions matrix for more details.

    Have to try to remember that. Not used it too much.


    Thanks for helping!

     

    -Tee-

  6. Posted

    30 minutes ago, Lars Fosdal said:

    There also is https://docwiki.embarcadero.com/Libraries/Sydney/en/System.TypInfo.GetEnumProp

    which returns a PPropInfo, which again contains a PropType: PPTypeInfo, which you then can use with GetEnumValue?

    This lead me one step closer.

      

      var LEnumValue: Integer;
  LEnumValue := GetEnumValue(LProperty.PropertyType.Handle, AValue);

  if (LEnumValue <> -1) and LProperty.IsWritable then
    LProperty.SetValue(FInstance, LEnumValue);

    With this I get the actual value, but setting the value does not work (More than  less same code is used elsewhere and they work).

     

    It raises  EInvalidCast with message 'Invalid class typecast'.

    Integer is correct value for the Enum, it is in  between bounds. This slightly baffles me now.
     

  7. Posted · Edited by Tommi Prami

    7 minutes ago, msohn said:

    I've been using TypeInfo.SetEnumProp for that - works for all Enums that are published properties. It basically is SetOrdProp with GetEnumValue shown by Dalija, so saves you figuring out the enum size. 

    Oh, I forgot to mention that should work public properties also, I modify original, I still can... MAybe it is now more clear what I am after...

     

    -Tee-

  8. Posted

    10 minutes ago, Dalija Prasnikar said:

    I would use TypeInfo instead of RTTI as it will be faster. This requires System.TypInfo 

      

    
procedure TMyThingy.SetEnumPropertyValue(const AValue: string);
begin
  PByte(@FEnumProp)^ := GetEnumValue(TypeInfo(TMyEnum), AValue);
end;

     

    You should pay attention on enum type size and use appropriate sized pointer when casting PByte(@EnumProp)^. This will also raise out of range exception if passed string does not match to any value in TMyEnum. You can catch that and set it to some default value if needed.


    I think I explained myself poorly. That won't work because it depends on TypeInfo(TMyEnum)

    My code must not know/depend on the (hardcoded) type, it should be dynamic.  Work with any given property, that is any type of Enum (some limitations may apply, but if works simple enums like one in example, it is OK).

  9. Posted · Edited by Tommi Prami

    Yellow,

     

    I have about following situation.

    FInstance is any TObject descendant and enum property can be any public or published Enum property, code must not link to hard coded enum type.
      

    procedure TMyThingy.SetEnumPropertyValue(const AValue: string);
var
  LContext: TRttiContext;
  LRtttiType: TRttiType;
  LProperty: TRttiProperty;
begin
  LContext := TRttiContext.Create;
  LRtttiType := LContext.GetType(FInstance.ClassType);
  LProperty := LRtttiType.GetProperty(FPropertyName);
  
  // Here I should convert lets say TMyEnum = (A, B, C) from string into the property value
  // if I call SetEnumPropertyValue('B') property FPropertyName from FInstance-object should be set.
end;

    This should be quite simple, couple lines of code most likely.

     

    Could not find sample code that was good enough fit to get this to work, there usually was too much knowns, like enum type TMyEnum,

     

    This should be totally dynamic.

    Circled around this quite long time, just could not find the way to connect all the dots...

     

    -Tee-
     

  13. Posted · Edited by Tommi Prami

    13 hours ago, Lars Fosdal said:

    @Tommi Prami Yes, the installer barfs on restarting the installation due to Navigator, but it should be able to recover. Mine did.

     

    Mine did not.

    Restarting encountered into same dll-error, don't remember which dll it was. and did not take screnn shot etc. 😞


    Coworker cant open IDE even after clean install... Freezes at the Splash Screen...
     

    -Tee-

  14. Posted

    Remember to uninstall Parnassus-plugins before installing.

    Web Installer failed because forgot to uninstall them first. Had to make installer to clean all settings.  

    Takes some time to get all settings as needed because of that. 

     

    -Tee-

  15. Posted

    On 3/29/2024 at 9:00 PM, kuzduk said:

    i already wrote new site address with ssl setificate without antivirus damage!!!!!!!!!!!!!

     

     

    not use old site adress without ssl with h1n : https://kuzduk.h1n.ru

     

    Moderators, pleace edit first post link to  https://kuzduk.ru/delphi/kulibrary

     

    Could you instead of the site update all to the GitHUB, so it would be much easier and better place to public open source library. And keep it up there, and if needed link your own site to the GirHUB and maintain only that actyively.

     

    -Tee-

  18. Posted

    5 minutes ago, Lars Fosdal said:

    Which again makes me wonder why not 

    
SELECT SUM(Field1) AS Total FROM YourSourceView

    but as mentioned, I suspect the example differs from the real world need...

    True,

    Calculating the sum was just placeholder of some calculation going on in the loop

    But very true, if can get sum forehand, would be smart to get it.

     

    -Tee-

  21. Posted · Edited by Tommi Prami

    44 minutes ago, Lars Fosdal said:

      

    
procedure ConnectFields(Query: TDataSet; const Fields: TArray<TField>; const Names: TArray<string>);
begin
  Assert(Length(Fields) = Length(Names), 'Number of fields and number of names must match');
  for var ix := 0 to Length(Fields) - 1
  do begin
    Fields[ix] := Query.FieldByName(Names[ix]);
    if not Assigned(Fields[ix])
    then raise Exception.Create(Format('Field %s not found.', [Names[ix]]); 
  end;
end
  
// usage
var
  Field1, Field2, Field3, Field4: TField;
begin
  ConnectFields(Query,
   [ Field1,   Field2,   Field3,   Field4], 
   ['Field1', 'Field2', 'Field3', 'Field4']);
...

     which doesn't save you that much code, really.

    Does not work, know because I've tried that approach in the past, and retried your code and it does nothing. (outside of procedure, which is the important part),

      

    // usage
var
  Field1, Field2, Field3, Field4: TField;
begin
  Field1 := nil; // ...   Field2,   Field3,   Field4
  ConnectFields(Query,
   [ Field1,   Field2,   Field3,   Field4], 
   ['Field1', 'Field2', 'Field3', 'Field4']);
 // Fields star as they are in here, nil or not nil, doesnt matter... But eassy to check by nilling the fields becore and after call.

     

    Other problem in this tat compiler starts to complain about Fields are uninitialized. But that is separate issue...

  22. Posted · Edited by Tommi Prami

    15 minutes ago, uligerhardt said:

    Seems like an array should be the way: 

    
type
  TMyFields = array[1..4] of TField;

procedure TForm1.FormCreate(Sender: TObject);
var
  LFields: TMyFields;
  i: Integer;
begin
  for i := Low(TMyFields) to High(TMyFields) do
    LFields[i] := Query.FieldByName('FIELD' + IntToStr(i));
end;

     

    Nice could be done something like that,. but field names are not indexed, usually and after that it is just the same as the my original example I am trying to solve...

     

    But Not looking for workaround...
     

    -Tee-

  23. Posted · Edited by Tommi Prami

    13 minutes ago, Sinspin said:

    You have also access to the list of fields.  

    
Query.Fields[0..N]

    No need to address the fields always by their names.

    Yes...

    But totally different thing...

    And would have exact same problem. Would need to initialize variables for indexes by name. Constant magic number indexes leads to buggy code.

    I am looking for solution for getting fields, and also solution for other cases I could adapt it to.

    Getting fields is just one use case of this type of procedure I would like to use...

     

    -Tee-

  24. Posted · Edited by Tommi Prami

    1 hour ago, Lars Fosdal said:

    So it is not about visual use?

    If not, I need to understand more about how the TFields will be used. 

    var
  LTotal: Double;
  LField1: TField;
  LField2: TField;
  LField3: TField;  
  LField4: TField;  
begin
  LField1 := Query.FieldByName('FIELD1');
  LField2 := Query.FieldByName('FIELD1');
  LField3 := Query.FieldByName('FIELD1');
  LField4 := Query.FieldByName('FIELD1'); 

  Query.First;
  while not Query.Eof do
  begin
    LTotal := LTotal + LField1.AsFloat;
    // More stuff done with local field variables...
    Query.Next;
  end;

    In this case, TDataSet and TField are RTL stuff or their descendants...

    So implementation should be kind that works if I have no control over the API of the class..

     

    -Tee-

  25. Posted

    8 minutes ago, Lars Fosdal said:

    There are many ways to do this. Will you need to reference the TField components in any way, or are they just for display or editing? Will there be a need for different data format handing for different fields? Different titles, sizes, validation, etc?

    In this case I get the field usually when they are needed in the loop, or get rid of with-clause or something like that.

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