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Uwe Raabe

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Posts posted by Uwe Raabe

  3. Posted

    Or you try a total different approach described in this article: Dataset Enumerator Reloaded

     

    The old repository can be found on GitHub: https://github.com/UweRaabe/DataSetEnumerator, although the current development happens in https://github.com/UweRaabe/CmonLib

     

    Taking your code example from above: 

    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;

    a corresponding solution based on my unit could look like this: 

    uses Cmon.DataSetHelper;

type
  [DBFields(mapAuto)]  // make sure record fields are named similar to DB fields!
  TMyFields = record
    Field1: Double;
    Field2: Double;
    Field3: Double;
    Field4: Double;
  end;

var
  LTotal: Double;
begin
  LTotal := 0;
  for var rec in Query.Records<TMyFields> do begin
    LTotal := LTotal + rec.Field1;
    // More stuff done with rec
  end;

     

  4. Posted

    6 minutes ago, dummzeuch said:

    I my opinion Delphi 12 + Update 1 is a bit little more stable

    There is no Delphi 12 Update 1 (yet), only Delphi 12 with Patch 1.

     

    During times a common rule had established to wait for the first Update after an initial release before starting to use a Delphi version in production. That doesn't imply not to install and start using it - just not for production. JM2C

    • Like 2

  5. Posted

    1 hour ago, Lars Fosdal said:

    Fields[ix] := Query.FieldByName(Names[ix]);

    This will only change the TField array item, but not the local variable FieldX as expected.

     

     A const or var array of TField is no replacement for a couple of var par: TField parameters. As soon as you construct that array parameter, the addresses of the local variables are gone, while their current content (which may be undefined here) is copied to the array item.

     

    Perhaps this may be a better approach (didn't try as I am too lazy to create a fake dataset with these fields): 

    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.FindField(Names[ix]);
    if not Assigned(Fields[ix]^) then
      raise Exception.Create(Format('Field %s not found.', [Names[ix]]));
  end;
end;

procedure Test;
var
  Field1, Field2, Field3, Field4: TField;
begin
  ConnectFields(Query,
   [ @Field1,   @Field2,   @Field3,   @Field4],
   ['Field1', 'Field2', 'Field3', 'Field4']);
   ...
end;

     

    • Like 1
    • Thanks 2

  9. Posted

    This is indeed very instable. One would need to extend the current internals significantly to make this work. Nevertheless one can achieve some results by setting AcceptExpressions to True and override these two methods: 

    type
  TNumberBox = class(Vcl.NumberBox.TNumberBox)
  protected
    function GetValidCharSet(AAcceptExpressions: Boolean): TSysCharSet; override;
    function IsNumericText(const AText: string): Boolean; overload; override;
  end;

function TNumberBox.GetValidCharSet(AAcceptExpressions: Boolean): TSysCharSet;
begin
  Result := inherited GetValidCharSet(AAcceptExpressions);
  if Mode = nbmFloat then
    Result := Result + ['e', 'E', '+', '-'];
end;

function TNumberBox.IsNumericText(const AText: string): Boolean;
begin
  Result := inherited;
  if AText.LastIndexOfAny(['e', 'E']) = AText.Length - 1 then
    Result := False;
end;

     

    • Like 1

  13. Posted

    SetThreadDpiAwarenessContext has to be wrapped around the creation of a top level window handle to work correctly. All child windows then inherit the context of the top level one. This rules out any docked forms or frames, which explains why it is not feasible for the Embedded Designer. (Fun fact: an undocked designer window would have worked with that.)

     

    A solution for this problem could be SetThreadDpiHostingBehavior and AFAIK that is something Embarcadero is investigating in.

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