无法从 DLL 中获取类/实例。您可以将接口交给类,而不是类。下面是一个简单的例子
// The Interface-Deklaration for Main and DLL
unit StringFunctions_IntfU;
interface
type
IStringFunctions = interface
['{240B567B-E619-48E4-8CDA-F6A722F44A71}']
function CopyStr( const AStr : WideString; Index, Count : Integer ) : WideString;
end;
implementation
end.
简单的DLL
library StringFunctions;
uses
StringFunctions_IntfU; // use Interface-Deklaration
{$R *.res}
type
TStringFunctions = class( TInterfacedObject, IStringFunctions )
protected
function CopyStr( const AStr : WideString; Index : Integer; Count : Integer ) : WideString;
end;
{ TStringFunctions }
function TStringFunctions.CopyStr( const AStr : WideString; Index, Count : Integer ) : WideString;
begin
Result := Copy( AStr, Index, Count );
end;
function GetStringFunctions : IStringFunctions; stdcall; export;
begin
Result := TStringFunctions.Create;
end;
exports
GetStringFunctions;
begin
end.
现在是简单的主程序
uses
StringFunctions_IntfU; // use Interface-Deklaration
// Static link to external function
function GetStringFunctions : IStringFunctions; stdcall; external 'StringFunctions.dll' name 'GetStringFunctions';
procedure TMainView.Button1Click( Sender : TObject );
begin
Label1.Caption := GetStringFunctions.CopyStr( Edit1.Text, 1, 5 );
end;