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copied!<p>It depends on your Item.SomeProperty type. If it is Variant, or if there is a variant to be evaluated before it, it will be evaluated and cause AV.</p> <p>Edit : Forget to mention the workaround : If the SomeProperty is Variant type, you can use </p> <pre><code> if Assigned(Item) and StrToBool(Item.SomeProperty) then </code></pre> <p>It do spend some time to convert the variable to String then back to boolean but at lease it can satisfy all cases of being true / false / non-existence. </p> <p>Below is a test case for you to see :</p> <pre><code>unit Unit4; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Generics.Collections; type TTestObj = class public V : Variant; I : Integer; end; TForm4 = class(TForm) btn1: TButton; btn2: TButton; btn3: TButton; procedure btn1Click(Sender: TObject); procedure btn2Click(Sender: TObject); procedure btn3Click(Sender: TObject); private { Private declarations } public { Public declarations } TOV : TTestObj; end; var Form4: TForm4; implementation {$R *.dfm} procedure TForm4.btn1Click(Sender: TObject); begin if Assigned(TOV) and (TOV.I = 10) then ShowMessage('You will never see this though no AV!'); end; procedure TForm4.btn2Click(Sender: TObject); begin if Assigned(TOV) and StrToBool(TOV.V) then ShowMessage('You will not see AV with StrToBool!'); if Assigned(TOV) and TOV.V then ShowMessage('You will never see this but AVed!'); end; procedure TForm4.btn3Click(Sender: TObject); var V : Variant; begin V := False; if Assigned(TOV) and V and (TOV.I = 10) then ShowMessage('You will see AV!'); end; end. </code></pre>

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