我在delphi中调用excel vb api函数copy sheets("sheet1").copy复制工作表 我想复制到最后但是定义说明是： expression.Copy([Before],[After]) Before 语法 3： Variant 类型，可选。复制工作表放到此工作表之前。如果已经指定了 After，则不能指定 Before。 After Variant 类型，可选。复制工作表放到此工作表之后。如果已经指定了 Before，则不能指定 After。 所以我要设置第2个参数after，忽略第一个参数before

EmptyParam is what you need. 

引言: EmptyParam is what you need. >< face="Verdana, Arial, Helvetica"> 我很认真的做....... procedure a(x:string='10';y:string='20'); begin showmessage(x y); end; procedure TForm1.Button1Click(Sender: TObject); begin a(EmptyParam,'f'); end; "Invalid variant type conversion." EmptyParam variable Specifies that an optional parameter on a dual interface is not used. Unit System Category COM utilities var EmptyParam: OleVariant; Description When marshaling interface calls that include optional parameters, COM still requires a value for those parameters even when they are not used. Pass EmptyParam as that value to indicate that the parameter is not used. 哎，人生无趣啊

引言: expression.Copy([Before],[After])

使用 vba 可以這樣下: expression.Copy(Before:=xxxxxx); 或 expression.Copy(After:=xxxxxxx); 這樣就可以了. 直接指明是那個傳入參數和值即可!

引言:

procedure a(x:string='10';y:string='20');
begin
    showmessage(x y);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
    a(EmptyParam,'f');
end;

EmptyParam can only be used as variant. For example ExcelWorkSheet1.Copy(EmptyParam,EmptyParam) but in your case x wants a string and of course EmptyParam cannot be converted into a string.

引言:

引言:

procedure a(x:string='10';y:string='20');
begin
    showmessage(x y);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
    a(EmptyParam,'f');
end;

EmptyParam can only be used as variant. For example ExcelWorkSheet1.Copy(EmptyParam,EmptyParam) but in your case x wants a string and of course EmptyParam cannot be converted into a string.

yes ,you r rignt,i passed the test thanks

引言:

引言: expression.Copy([Before],[After])

使用 vba 可以這樣下: expression.Copy(Before:=xxxxxx); 或 expression.Copy(After:=xxxxxxx); 這樣就可以了. 直接指明是那個傳入參數和值即可!

感谢各位相助，不知简体有否影响各位阅读？是否有乱码