在程式中匯入了一個OCX控制元件，其中使用的引數為如下兩個：
function receiveMessage(var NetID: Smallint; var NodeID: Smallint; var UnitID: Smallint;
MessageType: OleVariant): OleVariant;
function sendFinsCommand(NetID: Smallint; NodeID: Smallint; UnitID: Smallint;
Message: OleVariant): Integer; overload;
撰寫程式為：
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, OleCtrls, DBOleCtl, FINSMSGCTLLib_TLB;
type
TForm1 = class(TForm)
fnsmsg1: TFinsMsg;
btn1: TButton;
edt1: TEdit;
procedure btn1Click(Sender: TObject);
procedure fnsmsg1Receive(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.btn1Click(Sender: TObject);
begin
fnsmsg1.sendFinsCommand(0,2,0,'0701');
end;
procedure TForm1.fnsmsg1Receive(Sender: TObject);
var
a,b,c:SmallInt;
messagefins:OleVariant;
s:string;
begin
a:=0;
b:=2;
c:=0;
s := fnsmsg1.receiveMessage(a,b,c,messagefins);
end;
end.
單擊“btn1",程式執行，發送指令：fnsmsg1.sendFinsCommand(0,2,0,'0701');順序執行。控制元件接收到指令后，開始自動運行fnsmsg1Receive函式，到 s := fnsmsg1.receiveMessage(a,b,c,messagefins);行，系統拋出如下錯誤：
Project Project1.exe raised exception class EOleException with message "Unsupported Variant Type on the Method argument".Process stopped.
我把messagefins變為String型別也是一樣的。
請大神給出較為詳細的分析，最好能給出點嗎，謝謝！
uj5u.com熱心網友回復：
messagefins的值是多少，從代碼上看，a,b,c都有賦值，messagefins沒有賦值？uj5u.com熱心網友回復：
試試 s := fnsmsg1.receiveMessage(0,2,0,'0701'); 可有錯誤！轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/88796.html
標籤：VCL組件開發及應用