The title pretty much says it all. I\'m using a TClientDataset to store an array of objects, and one of the objects has a member defined as a set of an enumerat
You can convert them to Byte, like this:
var
States : TUpdateStatusSet; // Can be any set, I took this one from DB.pas unit
SetAsAInteger: Integer;
dbs: Pointer; // Here's the trick
begin
States := [usModified, usInserted]; // Putting some content in that set
dbs := @States;
SetAsAInteger := PByte(dbs)^;
//Once you got it, SetAsAInteger is just another ordinary integer variable.
//Use it the way you like.
end;
To recover from anywhere:
var
MSG: string;
Inserted, Modified: string;
States: TUpdateStatusSet;
MySet: Byte;
begin
while not ClientDataSet.Eof do
begin
//That's the part that interest us
//Convert that integer you stored in the database or whatever
//place to a Byte and, in the sequence, to your set type.
iSet := Byte(ClientDatasetMyIntegerField);// Sets are one byte, so they
// fit on a byte variable
States := TUpdateStatusSet(iSet);
//Conversion finished, below is just interface stuff
if usInserted in States then
Inserted := 'Yes';
if usModified in States then
Modified := 'Yes';
MSG := Format('Register Num: %d. Inserted: %s. Modified:%s',
[ClientDataSet.RecNo, Inserted, Alterted]);
ShowMessage( MSG );
ClientDataset.Next;
end;
end;
You could use a TBytesField or a TBlobField
ClientDataSet1MySet: TBytesField, Size=32
var
MySet: set of Byte;
Bytes: array of Byte;
begin
MySet := [1, 2, 4, 8, 16];
// Write
Assert(ClientDataSet1MySet.DataSize >= SizeOf(MySet), 'Data field is too small');
SetLength(Bytes, ClientDataSet1MySet.DataSize);
Move(MySet, Bytes[0], SizeOf(MySet));
ClientDataSet1.Edit;
ClientDataSet1MySet.SetData(@Bytes[0]);
ClientDataSet1.Post;
// Read
SetLength(Bytes, ClientDataSet1MySet.DataSize);
if ClientDataSet1MySet.GetData(@Bytes[0]) then
Move(Bytes[0], MySet, SizeOf(MySet))
else
MySet := []; // NULL
end;
Based on the example of Andreas, but made somewhat simpler and clearer IMHO.
Tested on XE2
You could use a TBytesField or a TBlobField
ClientDataSet1MySet: TBytesField, Size=32
1) Writing
var
MySet: set of Byte;
Bytes: TBytes;
begin
MySet := [0];
// Write
Assert(ClientDataSet1Test.DataSize >= SizeOf(MySet), 'Data field is too small');
SetLength(Bytes, ClientDataSet1Test.DataSize);
Move(MySet, Bytes[0], SizeOf(MySet));
ClientDataSet1.Edit;
ClientDataSet1Test.AsBytes := Bytes;
ClientDataSet1.Post;
end;
2) Reading
var
MyResultSet: set of Byte;
begin
Move(ClientDataSet1Test.AsBytes[0], MyResultSet, ClientDataSet1Test.DataSize);
end;