文件拷贝时的进度表为什么不显示 (100分)

我在书上抄了一段程序，拷贝文件时显示进度条，可是进度条不显示进度，一直到拷贝结束
才显示直接到了100%，请指教

repeat
BlockRead(SrcFile, Buffer, SizeOf(Buffer), BytesRead);
if BytesRead > 0 then
begin
BlockWrite(DestFile, Buffer, BytesRead, BytesWritten);
if BytesRead <> BytesWritten then
raise Exception.Create('拷贝文件错误')
else begin
TotalRead := TotalRead + BytesRead;
//fcopy.prbCopy.Position := Trunc(TotalRead / Fsize) * 100;
//fcopy.prbCopy.Update;
prbCopy.Position := Trunc(TotalRead / Fsize) * 100;
Application.processmessage
end;
end
until BytesRead = 0;
還有prbCopy.Min和Max要先賦值好﹐特別是Max。

prbCopy.Position := Trunc(TotalRead / Fsize) * 100;
prbCopy.repaint;

主动刷新一下滚动条。

用CopyFileEx最好。

not Trunc(TotalRead / Fsize) * 100
should be Trunc(TotalRead / Fsize * 100)