Mega Code Archive
How to change properties of objects just by name
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Title: How to change properties of objects just by name?
Question: How can i access properties of classes that are not implemented via the uses-clause, just knowing their names ( by string)?
Answer:
You have to use the TypInfo unit.
Simple properties, like strings and integer, can be accessed in the
following manner:
-------------------------------------------------------------
Uses TypInfo;
procedure AlterProp(AName, APropName, AValue:string);
var i : integer;
C : TComponent;
begin
// Run through all Components to find the right Component
for i:=0 to Form1.Componentcount-1 do
begin
C := Form1.Components[i];
if (C.Name = AName) then
begin
SetPropValue(C,APropName, AValue);
end;
end;
end;
-------------------------------------------------------------
Now there are also some Properties like Font. How do i reach those
sub-properties?
Here is a solution to that:
-------------------------------------------------------------
Uses TypInfo;
procedure AlterFontColor(AName:string; AColor:TColor);
var i : integer;
C : TComponent;
AObj : TObject;
begin
// Run through all Components to find the right Component
for i:=0 to Form1.Componentcount-1 do
begin
C := Form1.Components[i];
if (C.Name = AName) then
begin
AObj := GetObjectProp(C,'Font');
SetPropValue(AObj,'Color',AColor);
end;
end;
end;
-------------------------------------------------------------
And finally you have many indexed properties like TStrings or stuff.
Now how do i reach those indexed properties?
All indexed properties are stored in TCollection-Objects. So you
have to Typecast them like in the following function:
-------------------------------------------------------------
Uses TypInfo;
procedure AlterIndexObject(ACompName, APropName:string; ACaption: string);
var i : integer;
C : TComponent;
ACollectionItem, AObj : TObject;
begin
// Run through all Components to find the right Component
for i:=0 to Form1.Componentcount-1 do
begin
C := Form1.Components[i];
if (C.Name = ACompName) then
begin
AObj:= GetObjectProp(C,APropName);
ACollectionItem := TCollection(AObj).Items[0];
SetPropValue(ACollectionItem, 'Caption', ACaption);
end;
end;
end;
-------------------------------------------------------------
There are many possibilities for this functions to use in your projects.
Mainly there are usefull for language-changings or skin-components.
The possibilities are endless.
I hope my article was somewhat usefull for you.
I like to share knowledge with other developers.
keep on coding :-)
Jrgen Sommer
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