我正在尝试在Delphi中为Excel构建一个RTD服务器,我无法使这部分代码工作:
function TRtdServer.RefreshData(var TopicCount: Integer): PSafeArray;
//Called when Excel is requesting a refresh on topics. RefreshData will be called
//after an UpdateNotify has been issued by the server. This event should:
//- supply a value for TopicCount (number of topics to update)
//- The data returned to Excel is an Object containing a two-dimensional array.
// The first dimension represents the list of topic IDs.
// The second dimension represents the values associated with the topic IDs.
var
Data : OleVariant;
begin
//Create an array to return the topics and their values
//note:The Bounds parameter must contain an even number of values, where each pair of values specifies the upper and lower bounds of one dimension of the array.
Data:=VarArrayCreate([0, 1, 0, 0], VT_VARIANT);
Data[0,0]:=MyTopicId;
Data[1,0]:=GetTime();
if Main.Form1.CheckBoxExtraInfo.Checked then Main.Form1.ListBoxInfo.Items.Add('Excel called RefreshData. Returning TopicId: '+IntToStr(Data[0,0])+' and Value: '+Data[1,0]);
TopicCount:=1;
// RefreshTimer.Enabled:=true;
//Result:=PSafeArray(VarArrayAsPSafeArray(Data));
Result:=PSafeArray(TVarData(Data).VArray);
end;
我不确定这部分:
Result:=PSafeArray(TVarData(Data).VArray);
但它可能是代码的任何部分。 Excel只是在包含rtd()函数调用的单元格中没有显示任何结果。我确实设法在第一次Excel调用我的“ConnectData”函数时将结果输入到单元格中,simple函数返回一个字符串而不是PSafeArray(尽管第一次调用该函数时无法产生结果(N / A)。更改RTD()调用中的主题后,它显示结果(仅一次))
我将代码基于来自https://blog.learningtree.com/excel-creating-rtd-server-c/的C#中的示例
谁能指出我正确的方向?
OleVariant
拥有它拥有的数据,并在其超出范围时释放该数据。所以你返回一个无效的PSafeArray
指针到Excel。你需要:
function TRtdServer.RefreshData(var TopicCount: Integer): PSafeArray;
var
Data : OleVariant;
begin
...
Result := PSafeArray(TVarData(Data).VArray);
TVarData(Data).VArray = nil; // <-- add this
end;
SafeArrayCopy()
制作数组的副本,然后返回副本:
uses
..., ActiveX;
function TRtdServer.RefreshData(var TopicCount: Integer): PSafeArray;
var
Data : OleVariant;
begin
...
OleCheck(
SafeArrayCopy(
PSafeArray(TVarData(Data).VArray),
Result
)
);
end;