如何在SetRange处于活动状态时获取FireDAC记录计数

Question

I'm slowly moving from ClientDataSet to FireDAC FDQuery components in my projects (Delphi 10 Seattle).

One trick I often use with CDS is to check record count on a range.

That is:

CDS.SetRange([Value1][Value2]);  
k := CDS.RecordCount;  
case k of  
  1 : DoSingleThing;  
  2 : DoDoubleThing;  
else  
  BailOnWrongCount;  
end;  

Because I need the entire set of data available at the same time, I use FetchOptions.Mode := fmAll when first opening the query.

Doing FDQuery.SetRange([Value1][Value2]); then calling FDQuery.RecordCount always returns the record count of the entire dataset (as per fmAll) - not the current range.

I'm having to loop through the range counting records manually.

Is there a simpler way to get the number of records in the current range?

Answer 1

将FetchOptions.RecordCountMode设置为cmVisible： http ：//docwiki.embarcadero.com/Libraries/Seattle/en/FireDAC.Stan.Option.TFDFetchOptions.RecordCountMode