I have a FDQuery that feeds data to a grid.
When the user clicks on a column I want the grid to order on that column.
Because I want to be able to sort on multiple columns, I cannot use the autosort option of the grid.
I tried the following code in my proof of concept.
However it does not work.
procedure TForm31.JvDBGrid1TitleBtnClick(Sender: TObject; ACol: Integer;
Field: TField);
const
sDesc = 1;
sASC = 2;
sNone = 0;
var
i: integer;
SortClause: string;
AField: TField;
AIndex: TFDIndex;
begin
case Field.Tag of
sDesc: Field.Tag:= sASC;
sASC: Field.Tag:= sNone;
sNone: Field.Tag:= sDesc;
end;
SortClause:= '';
FDQuery1.Indexes.BeginUpdate;
try
FDQuery1.Indexes.Clear;
for i:= 0 to JvDBGrid1.Columns.Count - 1 do begin
AField:= JvDBGrid1.Columns[i].Field;
if AField.Tag <> sNone then begin
AIndex:= FDQuery1.Indexes.Add;
AIndex.Name:= AField.FieldName;
AIndex.Fields:= AField.FieldName;
//AIndex.Options:= [soNoCase, soNullFirst, soDescNullLast, soDescending, soUnique, soPrimary, soNoSymbols]
case AField.Tag of
sDESC: AIndex.Options:= [soDescNullLast];
sASC: AIndex.Options:= [];
end;
AIndex.Active:= true;
end;
end;
finally
FDQuery1.Indexes.EndUpdate;
FDQuery1.Refresh;
end;
end;
It does not matter whether the Query already has an order by clause or not.
What am I doing wrong?
P.S. I'd rather not resort to constructing a custom order by clause but I know that's an option.
I think you may be missing a step, namely setting the FDQuery's IndexName to the name of the added index. Apparently. setting the added index's Active property is insufficient.
The following works fine for me against the MS Sql Server pubs database Authors table:
procedure TForm1.AddFDIndex;
var
AIndex : TFDIndex;
begin
AIndex := FDQuery1.Indexes.Add;
AIndex.Name := 'ByCityThenlname';
AIndex.Fields := 'city;au_lname';
AIndex.Active := True;
FDQuery1.IndexName := AIndex.Name;
end;
Btw, I'm not sure what your code is supposed to do if more than one column is tagged to be included in the index, but I'll leave that to you ;=)
Related
I am writing which component will run through the array like ['form1.Button1', 'form1.memo1', 'form1'] - like
And put the showms2 handler on it (form1.Button1.onclick: = showms2)
var
comp: array of Tcomponent;
met: Tmethod;
start off
setlength (comp, Lines.Count);
for i: = 0 to Lines.Count-1 do
start off
comp [i]: = (FindComponent (Lines.Names [i]) as TControl);
met: = GetMethodProp (comp [i], 'OnClick');
meth.Code: = form1.MethodAddress ('showms2');
met.Data: = 0;
// When splitting into elements, nothing happens, is there an alternative?
FindComponent() does not work the way you are using it. You need to specify only the name of a component that is directly owned by the component being searched, you can't specify a chain of components, ie Form1.FindComponent('Form1.Button1') won't ever work, but Form1.FindComponent('Button1') will work, if Form1 owns Button1.
Also, if you are going to set both TMethod.Code and TMethod.Data then calling GetMethodProp() is completely redundant and should be removed.
Also, you need to use SetMethodProp() to actually assign the TMethod to the target event.
Try this instead:
var
comp: TComponent;
met: TMethod;
i: Integer;
begin
for i := 0 to Lines.Count-1 do
begin
comp := FindComponent(Lines.Names[i]);
if comp <> nil then
begin
if IsPublishedProp(comp, 'OnClick') then
begin
meth.Code := Form1.MethodAddress('showms2');
meth.Data := Form1;
SetMethodProp(comp, 'OnClick', met);
end;
end;
end;
end;
I would like to ask some help on displaying my datasource’s clientname at the bottom of my stacked bar chart. It seems from all the examples that I researched, the bottom chart axis label is set "automatically" by TeeChart looking at the datasource. However I cant seem to get it to work. Below is a picture of what I am trying to achieve.
Picture of what I am trying to achieve
I have three series' which I use to build the stacked chart. I have included a picture of each datasource I use for each query.
Datasources for three series' queries
From my research it seems I can also use the DBChart1GetAxisLabel() to custom set the labels. But I am struggling to understand how to ensure that the correct custom label name is associated with the correct "clientname" from my queries.
Here is a code sample of how I build the charts:
procedure TfrmSupplierAnalytics.btnOKClick(Sender: TObject);
var
S,NewTypeStr, test, clientSql : string;
var seriasNormalOrders:TBarSeries;
var seriasCreditNoteOrders:TBarSeries;
var seriasPartialOrders:TBarSeries;
N, i : integer;
begin
qCreditNoteOrders.Close;
qNormalOrders.Close;
qPartialOrders.Close;
qGetClientIdFromName.Close;
qClients.Close;
DBChart1.CleanupInstance;
DBChart1.ClearChart;
try
for N := 0 to clbClients.Items.Count-1 do
if clbClients.State[N] = cbChecked then begin
test := string(clbClients.Items[N]);
NewTypeStr := NewTypeStr + '(E.clientid = '+
IntToStr(FindClientID(test)) + ')';
clientSql := clientSql + NewTypeStr;
NewTypeStr := ' or ';
end;
except
on E : Exception do
ShowMessage(E.ClassName+' error raised, with message :
'+E.Message);
end;
OpenQueryCreditNoteOrders(clientSql);
OpenQueryPartialOrders(clientSql);
OpenQueryNormalOrders(clientSql);
seriasNormalOrders :=TBarSeries.Create(self);
DBChart1.AddSeries(seriasNormalOrders);
seriasCreditNoteOrders :=TBarSeries.Create(self);
DBChart1.AddSeries(seriasCreditNoteOrders);
seriasPartialOrders :=TBarSeries.Create(self);
DBChart1.AddSeries(seriasPartialOrders);
seriasNormalOrders.MultiBar := mbStacked;
seriasCreditNoteOrders.MultiBar := mbStacked;
seriasPartialOrders.MultiBar := mbStacked;
seriasNormalOrders.Marks.Visible := true;
seriasNormalOrders.MarksLocation:= mlCenter;
seriasNormalOrders.MarksOnBar := True;
seriasNormalOrders.YValues.ValueSource := 'NormalOrders';
seriasNormalOrders.DataSource := qNormalOrders;
seriasNormalOrders.Title := 'Correct Orders';
seriasNormalOrders.Marks.Visible := True;
seriasNormalOrders.Marks.AutoPosition := true;
seriasCreditNoteOrders.YValues.ValueSource := 'CreditNoteOrders';
seriasCreditNoteOrders.DataSource := qCreditNoteOrders;
seriasCreditNoteOrders.Title := 'Credit Note Orders';
seriasPartialOrders.YValues.ValueSource := 'PartialOrders';
seriasPartialOrders.DataSource := qPartialOrders;
seriasPartialOrders.Title := 'Short Orders';
seriasNormalOrders.CheckDataSource;
seriasCreditNoteOrders.CheckDataSource;
seriasPartialOrders.CheckDataSource;
end;
So, just to sum up, is there some setting in my code which I am missing that would show the "clientname" below each stacked bar, or must I use custom labels?
If I must use custom labels, I would appreciate some direction on how to ensure that I replace the correct "clientname" from the datasource to the correct ValueIndex in the DBChart1GetAxisLabel?
Thanks in advance.
I managed to get an answer.
You could set the XLabelsSource to show the text from the DataSource and then set the series Marks.Style to smsValue to force it showing values instead of showing the labels. Ie:
<pre>
procedure TForm1.FormCreate(Sender: TObject);
var ADOQuery1: TADOQuery;
i: Integer;
begin
ADOQuery1:=TADOQuery.Create(Self);
with ADOQuery1 do
begin
ConnectionString:='Provider=MSDASQL.1;Persist Security Info=False;Data
Source=TeeChart Pro Database';
SQL.Add('SELECT SALARY, LASTNAME from Employee WHERE LASTNAME='#39'Smith'#39);
end;
for i:=0 to 1 do
with DBChart1.AddSeries(TBarSeries) as TBarSeries do
begin
XLabelsSource:='LASTNAME';
DataSource:=ADOQuery1;
MultiBar:=mbStacked;
YValues.ValueSource:='SALARY';
Marks.Style:=smsValue;
end;
ADOQuery1.Open;
end;
</pre>
I tested it in my project and it works.
I'm kinda a Delphi-newbie and I don't get how the Sort method of a TList of Records is called in order to sort the records by ascending integer value.
I have a record like the following:
type
TMyRecord = record
str1: string;
str2: string;
intVal: integer;
end;
And a generic list of such records:
TListMyRecord = TList<TMyRecord>;
Have tried to find a code-example in the help files and found this one:
MyList.Sort(#CompareNames);
Which I can't use, since it uses classes. So I tried to write my own compare function with a little different parameters:
function CompareIntVal(i1, i2: TMyRecord): Integer;
begin
Result := i1.intVal - i2.intVal;
end;
But the compiler always throws a 'not enough parameters' - error when I call it with open.Sort(CompareIntVal);, which seems obvious; so I tried to stay closer to the help file:
function SortKB(Item1, Item2: Pointer): Integer;
begin
Result:=PMyRecord(Item1)^.intVal - PMyRecord(Item2)^.intVal;
end;
with PMyRecord as PMyRecord = ^TMyRecord;
I have tried different ways of calling a function, always getting some error...
The Sort overload you should be using is this one:
procedure Sort(const AComparer: IComparer<TMyRecord>);
Now, you can create an IComparer<TMyRecord> by calling TComparer<TMyRecord>.Construct. Like this:
var
Comparison: TComparison<TMyRecord>;
....
Comparison :=
function(const Left, Right: TMyRecord): Integer
begin
Result := Left.intVal-Right.intVal;
end;
List.Sort(TComparer<TMyRecord>.Construct(Comparison));
I've written the Comparison function as an anonymous method, but you could also use a plain old style non-OOP function, or a method of an object.
One potential problem with your comparison function is that you may suffer from integer overflow. So you could instead use the default integer comparer.
Comparison :=
function(const Left, Right: TMyRecord): Integer
begin
Result := TComparer<Integer>.Default.Compare(Left.intVal, Right.intVal);
end;
It might be expensive to call TComparer<Integer>.Default repeatedly so you could store it away in a global variable:
var
IntegerComparer: IComparer<Integer>;
....
initialization
IntegerComparer := TComparer<Integer>.Default;
Another option to consider is to pass in the comparer when you create the list. If you only ever sort the list using this ordering then that's more convenient.
List := TList<TMyRecord>.Create(TComparer<TMyRecord>.Construct(Comparison));
And then you can sort the list with
List.Sort;
The concise answer:
uses
.. System.Generics.Defaults // Contains TComparer
myList.Sort(
TComparer<TMyRecord>.Construct(
function(const Left, Right: TMyRecord): Integer
begin
Result := Left.intVal - Right.intVal;
end
)
);
I want to share my solution (based on the input I have gathered here).
It's a standard setup. A filedata class that holds data of a single file in a generic TObjectList. The list has the two private attributes fCurrentSortedColumn and fCurrentSortAscending to control the sort order. The AsString-method is the path and filename combined.
function TFileList.SortByColumn(aColumn: TSortByColums): boolean;
var
Comparison: TComparison<TFileData>;
begin
result := false;
Comparison := nil;
case aColumn of
sbcUnsorted : ;
sbcPathAndName: begin
Comparison := function(const Left, Right: TFileData): integer
begin
Result := TComparer<string>.Default.Compare(Left.AsString,Right.AsString);
end;
end;
sbcSize : begin
Comparison := function(const Left, Right: TFileData): integer
begin
Result := TComparer<int64>.Default.Compare(Left.Size,Right.Size);
if Result = 0 then
Result := TComparer<string>.Default.Compare(Left.AsString,Right.AsString);
end;
end;
sbcDate : begin
Comparison := function(const Left, Right: TFileData): integer
begin
Result := TComparer<TDateTime>.Default.Compare(Left.Date,Right.Date);
if Result = 0 then
Result := TComparer<string>.Default.Compare(Left.AsString,Right.AsString);
end;
end;
sbcState : begin
Comparison := function(const Left, Right: TFileData): integer
begin
Result := TComparer<TFileDataTestResults>.Default.Compare(Left.FileDataResult,Right.FileDataResult);
if Result = 0 then
Result := TComparer<string>.Default.Compare(Left.AsString,Right.AsString);
end;
end;
end;
if assigned(Comparison) then
begin
Sort(TComparer<TFileData>.Construct(Comparison));
// Control the sort order
if fCurrentSortedColumn = aColumn then
fCurrentSortAscending := not fCurrentSortAscending
else begin
fCurrentSortedColumn := aColumn;
fCurrentSortAscending := true;
end;
if not fCurrentSortAscending then
Reverse;
result := true;
end;
end;
I found a much simpler modified sort function to alphabetize a TList of records or nonstandard list of items.
Example
PList = ^TContact;
TContact = record //Record for database of user contact records
firstname1 : string[20];
lastname1 : string[20];
phonemobile : Integer; //Fields in the database for contact info
phonehome : Integer;
street1 : string;
street2 : string;
type
TListSortCompare = function (Item1,
Item2: TContact): Integer;
var
Form1: TForm1;
Contact : PList; //declare record database for contacts
arecord : TContact;
Contacts : TList; //List for the Array of Contacts
function CompareNames(i1, i2: TContact): Integer;
begin
Result := CompareText(i1.lastname1, i2.lastname1) ;
end;
and the function to call to sort your list
Contacts.Sort(#CompareNames);
What I'm trying to do is to get the list of fields in a class without an instance... for example:
TAClass=class
a_: Integer;
b_: Integer;
constructor (a,b Integer);
end;
I'm not being able to get the fieldTable from the VMT:
ovmt: PVmt;
ftable: PVmtFieldTable;
finfo: PVmtFieldEntry;
ovmt:=PVmt(TAClass);
ftable := ovmt^.vfieldtable
finfo := ftable^.fields[0]
this way I'm not gettig the list of fields
any help is welcome,
thanks in advance
Afaik the field tables in classic delphi and FPC only work for published fields. Published fields must be class fields (value types like integer must go via properties). Newer Delphi's also allow RTTI for non published fields, but that works differently (different untis), and FPC doesn't support that yet.
I hacked together a small demonstration example since the help for typinfo seems to be light on examples. Note the tpersistent derivation.
{$mode delphi}
uses typinfo,classes;
type
TAClass=class(Tpersistent)
a: tstringlist;
b: tlist;
end;
var
ovmt: PVmt;
FieldTable: PVMTFieldTable;
PVMTFieldEntry;
i: longint;
begin
ovmt := PVmt(TAClass);
while ovmt <> nil do
begin
FieldTable := PVMTFieldTable(ovmt^.vFieldTable);
if FieldTable <> nil then
begin
FieldInfo := #FieldTable^.Fields[0];
for i := 0 to FieldTable^.Count - 1 do
begin
writeln(fieldinfo^.name);
FieldInfo := PvmtFieldEntry(PByte(#FieldInfo^.Name) + 1 + Length(FieldInfo^.Name));
end;
end;
{ Try again with the parent class type }
ovmt:=ovmt^.vParent;
end;
end.
I have a record that looks similar to:
type
TNote = record
Title : string;
Note : string;
Index : integer;
end;
Simple. The reason I chose to set the variables as string (as opposed to an array of chars) is that I have no idea how long those strings are going to be. They can be 1 char long, 200 or 2000.
Of course when I try to save the record to a type file (file of...) the compiler complains that I have to give a size to string.
Is there a way to overcome this? or a way to save those records to an untyped file and still maintain a sort of searchable way?
Please do not point me to possible solutions, if you know the solution please post code.
Thank you
You can't do it with a typed file. Try something like this, with a TFileStream:
type
TStreamEx = class helper for TStream
public
procedure writeString(const data: string);
function readString: string;
procedure writeInt(data: integer);
function readInt: integer;
end;
function TStreamEx.readString: string;
var
len: integer;
iString: UTF8String;
begin
self.readBuffer(len, 4);
if len > 0 then
begin
setLength(iString, len);
self.ReadBuffer(iString[1], len);
result := string(iString);
end;
end;
procedure TStreamEx.writeString(const data: string);
var
len: cardinal;
oString: UTF8String;
begin
oString := UTF8String(data);
len := length(oString);
self.WriteBuffer(len, 4);
if len > 0 then
self.WriteBuffer(oString[1], len);
end;
function TStreamEx.readInt: integer;
begin
self.readBuffer(result, 4);
end;
procedure TStreamEx.writeInt(data: integer);
begin
self.WriteBuffer(data, 4);
end;
type
TNote = record
Title : string;
Note : string;
Index : integer;
procedure Save(stream: TStream);
end;
procedure TNote.Save(stream: TStream);
var
temp: TMemoryStream;
begin
temp := TMemoryStream.Create;
try
temp.writeString(Title);
temp.writeString(Note);
temp.writeInt(Index);
temp.seek(0, soFromBeginning);
stream.writeInt(temp.size);
stream.copyFrom(temp, temp.size);
finally
temp.Free;
end;
end;
I'll leave the Load procedure to you. Same basic idea, but it shouldn't need a temp stream. With the record size in front of each entry, you can read it and know how far to skip if you're looking for a certain record # instead of reading the whole thing.
EDIT: This was written specifically for versions of Delphi that use Unicode strings. On older versions, you could simplify it quite a bit.
Why not write this out as XML? See my session "Practical XML with Delphi" on how to get started with this.
Another possibility would be to make your records into classes descending form TComponent and store/retreive your data in DFM files.
This Stackoverflow entry shows you how to do that.
--jeroen
PS: Sorry my XML answer was a bit dense; I'm actually on the road for two conferences (BASTA! and DelphiLive! Germany).
Basically what you need to do is very simple: create a sample XML file, then start the Delphi XML Data Binding Wizard (available in Delphi since version 6).
This wizard will generate a unit for you that has the interfaces and classes mapping XML to Delphi objects, and a few helper functions for reading them from file, creating a new object, etc. My session (see the first link above) actually contains most of the details for this process.
The above link is a video demonstrating the usage of the Delphi XML Data Binding Wizard.
You could work with two different files, one that just stores the strings in some convenient way, the other stores the records with a reference to the strings. That way you will still have a file of records for easy access even though you don't know the size of the actual content.
(Sorry no code.)
TNote = record
Title : string;
Note : string;
Index : integer;
end;
could be translated as
TNote = record
Title : string[255];
Note : string[255];
Index : integer;
end;
and use Stream.writebuffer(ANodeVariable, sizeof(TNode), but you said that strings get go over 255 chars in this case IF a string goes over 65535 chars then change WORD to INTEGER
type
TNodeHeader=Record
TitleLen,
NoteLen: Word;
end;
(* this is for writing a TNode *)
procedure saveNodetoStream(theNode: TNode; AStream: TStream);
var
header: TNodeHeader;
pStr: PChar;
begin
...
(* writing to AStream which should be initialized before this *)
Header.TitleLen := Length(theNode.Title);
header.NodeLen := Length(theNode.Note);
AStream.WriteBuffer(Header, sizeof(TNodeHeader);
(* save strings *)
PStr := PChar(theNode.Title);
AStream.writeBuffer(PStr^, Header.TitleLen);
PStr := PChar(theNode.Note);
AStream.writebuffer(PStr^, Header.NoteLen);
(* save index *)
AStream.writebuffer(theNode.Index, sizeof(Integer));
end;
(* this is for reading a TNode *)
function readNode(AStream: TStream): TNode;
var
header: THeader
PStr: PChar;
begin
AStream.ReadBuffer(Header, sizeof(TNodeHeader);
SetLength(Result.Title, Header.TitleLen);
PStr := PChar(Result.Title);
AStream.ReadBuffer(PStr^, Header.TitleLen);
SetLength(Result.Note, Header.NoteLen);
PStr := PChar(Result.Note);
AStream.ReadBuffer(PStr^, Header.NoteLen);
AStream.ReadBuffer(REsult.Index, sizeof(Integer)(* 4 bytes *);
end;
You can use the functions available in this Open Source unit.
It allows you to serialize any record content into binary, including even dynamic arrays within:
type
TNote = record
Title : string;
Note : string;
Index : integer;
end;
var
aSave: TRawByteString;
aNote, aNew: TNote;
begin
// create some content
aNote.Title := 'Title';
aNote.Note := 'Note';
aNote.Index := 10;
// serialize the content
aSave := RecordSave(aNote,TypeInfo(TNote));
// unserialize the content
RecordLoad(aNew,pointer(aSave),TypeInfo(TNote));
// check the content
assert(aNew.Title = 'Title');
assert(aNew.Note = 'Note');
assert(aNew.Index = 10);
end;