Question

I am writing a procedure to close all adoquery created and open on a (any) form, the problem is I need to do a cast on the form to identify the components. how can I make a dynamic cast like shown in the example?

I need something like this

Procedure OpenADODataSets(Form:TForm;FormType:TClass);
...
...
(Form as FormType).ComponentCount

or

Procedure OpenADODataSets(Form:TForm;FormType:TClass);
...
...
FormType(Form).ComponentCount

this is the code.

Procedure OpenADODataSets(Form:TForm;FormType:TClass);
var
  i: integer;
begin

    for i:=0 to (Form as FormType).ComponentCount-1 do
     if (Form as FormType).Components[i].ClassType=TADOQuery then
       if not TADOQuery((Form as FormType).Components[i]).Active then
        TADOQuery((Form as FormType).Components[i]).Open;

end;

UPDATE

problem solved with the answer of @Edelcom

Procedure OpenADODataSets(Form:TForm);
var
  i: integer;
begin

    for i:=0 to Form.ComponentCount-1 do
     if Form.Components[i].ClassType=TADOQuery then
       if not TADOQuery(Form.Components[i]).Active then
        TADOQuery(Form.Components[i]).Open;

end;

Answer 1

Why do you need the (Form as FormType) (as I commented).
Looked up some of my own code, which works fine :

procedure TProgSettingsVisual.FillStandardSaveFilesForForm( const pForm: TForm;);
var i : integer;
    x : string;
    thisComponent : TComponent;
begin
   With pForm do
   begin
      for i := 0 to ComponentCount-1 do
      begin
         thisComponent := Components[i];

         x := LowerCase(Components[i].ClassName);


         if x = 'tovcinifilestore'
         then begin
            TOvcIniFileStore(Components[i]).IniFileName := FormSaveFile(pForm);
         end;

         if x = 'tovdformstate'
         then begin
             ...
         end;

         if x = 'tovccomponentstate'
         then begin
              ...