TValue is a Delphi data structure that can store different kinds of data types to ease the access to fields and method parameters. It is defined in the Rtti.pas unit.
Questions tagged [tvalue]
18 questions
10
votes
1 answer
Delphi XE: Where is my TValue.Equals()?
It seems that one, in my opinion mandatory method is missing from TValue; TValue.Equals(TValue).
So whats a fast and decent way of comparing 2 TValues, preferably without the use of TValue.ToString(), which allows false matches between variants,…
Marius
- 3,043
- 1
- 15
- 24
5
votes
4 answers
Converting an string to a enum type using TValue?
I want to convert an string to an enum type using TValue, I googled but I didn't find how to do that.
type
TEnumTest = (etFirst, etSecond);
var
D: TEnumTest;
begin
D := StrToENumTest('etFirst');
end;
function…
Fabricio Araujo
- 3,810
- 3
- 28
- 43
4
votes
1 answer
RTTI Delphi Create as TValue an n-dimensional matrix
Good day,
TValue is a Delphi-2010 and up RTTI feature.
Following on from my earlier question, I had tried to make recurrent function to return a TValue as a n-dimensional. matrix(2D, 3D, 4D...)
for example, this procedure will show a n-dimensional…
user558126
- 1,303
- 3
- 21
- 42
4
votes
1 answer
Delphi 2010 RTTI : Use TValue to store data
I would like to be able to use TValue to store Data in a TList<>. Like in :
type
TXmlBuilder = class
type
TXmlAttribute = class
Name: String;
Value: TValue; // TValue comes from Rtti
end;
TXmlNode = class
Name:…
ZeDalaye
- 689
- 7
- 17
3
votes
2 answers
Rtti data manipulation and consistency in Delphi 2010
Has anyone an idea, how I can make TValue using a reference to the original data? In my serialization project, I use (as suggested in XML-Serialization) a generic serializer which stores TValues in an internal tree-structure (similar to the…
Christian Metzler
- 2,971
- 5
- 24
- 30
3
votes
1 answer
Convert a TValue into TDateTime
How can I convert a TValue in TDateTime?
I see there are methods like AsInteger, AsDouble, etc. but nothing for TDateTime.
var
c : TRttiContext;
t : TRttiType;
f : TRttiField;
fieldValue : TValue;
fieldDateValue : TDateTime;
begin
c :=…
Alberto
- 2,881
- 7
- 35
- 66
2
votes
1 answer
TValue.AsType with enum types in Delphi
Writing this in Delphi
uses System.Classes;
...
var
A: TAlignment;
Value: TValue;
begin
Value := 0;
A := Value.AsType();
end;
raises EInvalidCast at AsType.
Is there a way to cast to any enumeration type from an integer value…
Jouni Aro
- 2,099
- 14
- 30
2
votes
1 answer
Delphi: different PTypeInfo for same type
I am a bit confused about PTypeInfo (and TypeInfo in general) in Delphi - Delphi 10 Seattle to be precise.
I ran into following problem:
We have an ORM framework (based on Spring4D). Now I want to extend it's abilities to map: Nullable integer…
Jan Drozen
- 894
- 2
- 12
- 28
2
votes
1 answer
TCheckBox.Data invalid typecast when using as TValue
Steps to reproduce:
-new firemonkey-application
-add TCheckBox to form
Now create a method with following code:
procedure TForm1.Foo;
var a,b:Integer; lVal:TValue;
begin
lVal:=TValue.From(42);
a:=lVal.AsInteger;
…
Art1st
- 123
- 2
- 11
1
vote
1 answer
Setting TValue record in Delphi from known type with RTTI
I have data that is being read in to a RESTful server in the form of name=value pairs.
The server code has a mapping of allowed "name" with a corresponding Delphi type and I wish to convert the "value" part (which is received in string format) to a…
David Moorhouse
- 1,573
- 3
- 14
- 19
1
vote
1 answer
TValue casting to other type
I have
uses
System.Rtti;
procedure TForm1.BitBtn1Click(Sender: TObject);
var
_UserString: string;
_CastedValue: TValue;
_IntExampleValue: TValue;
_DateTimeExampleValue: TValue;
begin
_UserString := '55';
_IntExampleValue :=…
Edijs Kolesnikovičs
- 1,627
- 3
- 18
- 34
0
votes
0 answers
get model.tvalues instead of model.bse from statsmodels summary2
I run a couple of regressions and I tabulate the results using summary2:
import statsmodels.api as sm
from statsmodels.iolib.summary2 import summary_col
mod1 = sm.OLS(df['y'], sm.add_constant(df['x']).fit()
mod2 = sm.OLS(df['y'],…
user9875321__
- 195
- 12
0
votes
1 answer
Blazor - FluentNumberField does not work unsigned types
I am not able to use an uint32, int16, ... when using the FluentNumberField.
Age
I cannot change the field type to int because this is what is expected in the Sql…
Coder6652
- 1
- 1
- 3
0
votes
1 answer
How to dynamically set TValue property of InputNumber component
We can assign and re-use the TValue with help of typeparam in the Blazor platform. But, how will we assign the TValue dynamically for Blazor InputNumber component?
code example:
[index.razor]
@*The below definiton is working*@
…
Berly Christopher
- 101
- 4
0
votes
0 answers
Embarcadero C++ Builder data structure that can store different complex data types
I am using C++ Builder 10.2.3.
I need to store from simple to complex data types, and restore them:
int
float
.
.
std::vector
std::vector() /* Transform is a user created class*/
etc...
I already tried Variant and TValue.…
Louis
- 75
- 6