Как изменить значение свойства компонента по имени?

Code:

function GetProperty(AControl: TPersistent; AProperty: String): PPropInfo;

var

i: Integer;

props: PPropList;

typeData: PTypeData;

begin

Result := nil;

if (AControl = nil) or (AControl.ClassInfo = nil) then

Exit;

typeData := GetTypeData(AControl.ClassInfo);

if (typeData = nil) or (typeData^.PropCount = 0) then

Exit;

GetMem(props, typeData^.PropCount * SizeOf(Pointer));

try

GetPropInfos(AControl.ClassInfo, props);

for i := 0to typeData^.PropCount - 1do

begin

with Props^[i]^ do

if (Name = AProperty) then

result := Props^[i];

end;

finally

FreeMem(props);

end;

procedure TForm1.Button1Click(Sender: TObject);

var

propInfo: PPropInfo;

begin

PropInfo := GetProperty(Button1.Font, 'Name');

if PropInfo <> nilthen

SetStrProp(Button1.Font, PropInfo, 'Arial');

end;

You can use RTTI to do this. Here is how to change a particular component:

Code:

procedure TForm1.BtnClick(Sender: TObject);

var

p: PPropInfo;

f: TFont;

begin

f := TFont.Create;

{Setup the font properties}

f.Name := 'Arial';

p := GetPropInfo(Sender.ClassInfo, 'Font');

if Assigned(p) then

SetOrdProp(Sender, p, Integer(f));

f.Free;

end;

To get at all the forms loop through the Screen global variable. For each form loop through its Components list calling the above procedure (or something close). If you only create your components at design time that is it. If you create some at runtime and the owner is not the form, then for each component loop through its Components list recursively to get at all the owned components.

I am building a routine that checks our forms for validity before deploying them. I would like to use some kind of structure that tests if a component type has access to a certain property, something like: " if (self.Controls[b] has Tag) then ...". Can anyone offer suggestions?

Here's an example of setting a string property for a component if it exists and another for an integer property:

Code:

{

}

procedure SetStringPropertyIfExists(AComp: TComponent; APropName: String;

AValue: String);

var

PropInfo: PPropInfo;

TK: TTypeKind;

begin

PropInfo := GetPropInfo(AComp.ClassInfo, APropName);

if PropInfo <> nilthen

begin

TK := PropInfo^.PropType^.Kind;

if (TK = tkString) or (TK = tkLString) or (TK = tkWString) then

SetStrProp(AComp, PropInfo, AValue);

end;

procedure SetIntegerPropertyIfExists(AComp: TComponent; APropName: String;

AValue: Integer);

var

PropInfo: PPropInfo;

begin

PropInfo := GetPropInfo(AComp.ClassInfo, APropName);

if PropInfo <> nilthen

begin

if PropInfo^.PropType^.Kind = tkInteger then

SetOrdProp(AComp, PropInfo, AValue);

end;

Tip by Xavier Pacheco

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