TxlDataSource Events

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The pseudo-code below describes the algorithm of data transfer for a given DataSource.

procedure TxlAbstractDataSource.Build;
begin

if Enabled then

try

Connect;
DoOnBeforeDataTransfer;
MacroProcessing(mtBefore, MacroBefore);
if Assigned(DataSet) then begin

// data from DataSet
if xrgoAutoOpen in Options then

DataSet.Open;

end
else begin

// unbound data
DoOnGetDataSourceInfo;
for i := 1 to FieldsCount do

DoOnGetFieldInfo;

end;
Parse;
if Assigned(DataSet) then

// data from DataSet
PutData

else begin

// unbound data
Eof := false;
while not Eof do

GetRecord(RecBuf, Eof);

end;
MacroProcessing(mtAfter, MacroAfter);
DoOnAfterDataTransfer;
OptionsProcessing;

finally

if Assigned(DataSet) and (xrgoAutoClose in Options) then

DataSet.Close;

Disconnect;

end;

When the process starts (Connect), pointers to all Excel interfaces are initialized. Then the OnBeforeDataTransfer event is triggered and the macro specified in the MacroBefore property is invoked. If the dataset isn't open and xrgoAutoOpen is on, the dataset is open. If the dataset isn't assigned, it is assumed that arbitrary data should be transferred to the report and the OnGetDataSourceInfo event is triggered. You use this event in order to define the structure of data and the number of fields. Each field causes triggering of the OnGetFieldInfo event where you supply XL Report with the field type. The template range is parsed and data are transferred In case of arbitrary data, each "record" is accompanied with triggering of the OnGetRecord event. The macro specified in the MacroBefore property is invoked and the OnAfterDataTransfer event is triggered. If the xrgoAutoClose option is on, the dataset is closed. All Excel interfaces are freed (Disconnect).

OnAfterDataTransfer

Is triggered after data transfer.

property OnAfterDataTransfer: TxlDataTransferHandleEvent;
type

TxlDataTransferHandleEvent = procedure (DataSource: TxlDataSource) of object;

Use this event to carry out any additional actions after data transfer. This also is the place where you can use the Excel interfaces described in corresponding sections of this Help. See also OnBeforeDataTransfer.

OnBeforeDataTransfer

Is triggered before data transfer.

property OnBeforeDataTransfer: TxlDataTransferHandleEvent;
type

TxlDataTransferHandleEvent = procedure (DataSource: TxlDataSource) of object;

Use this event to carry out any additional actions before data transfer. This also is the place where you can use the Excel interfaces described in corresponding sections of this Help. See also OnAfterDataTransfer.

OnGetDataSourceInfo

Allows describing the structure of arbitrary data.

property OnGetDataSourceInfo: TxlGetDataSourceInfo;
type

TxlGetDataSourceInfo = procedure (DataSource: TxlDataSource;

var FieldCount: integer) of object;

XL Report operates on tabular data so you have to define your data structure (even if you work with single record). If the DataSet property of the DataSources collection item is empty, this event is triggered. You define the number of fields in your by passing it in the FieldCount parameter. This causes triggering the OnGetFieldInfo event FieldCount times.

OnGetFieldInfo

Allows defining the field name and type for arbitrary data.

property OnGetFieldInfo: TxlGetFieldInfo;
type

TxlGetFieldInfo = procedure (DataSource: TxlDataSource;

const FieldIndex: integer;
var FieldName: string; var FieldType: TxlDataType) of object;

type

TxlDataType = (xdNotSupported, xdInteger, xdBoolean, xdFloat,

xdDateTime, xdString);

OnGetRecord

Is triggered for every "record" of an arbitrary data dataset.

property OnGetRecord: TxlGetRecord;
type

TxlGetRecord = procedure (DataSource: TxlDataSource;

const RecNo: integer;
var Values: OLEVariant; var EOF: boolean) of object;

OnMacro

Is triggered before invoking the VBA procedure specified in MacroBefore or MacroAfter properties.

property OnMacro: TxlOnMacro;
type

TxlOnMacro = procedure (Report: TxlReport; DataSource: TxlDataSource;

const AMacroType: TxlMacroType; const AMacroName: string;
var Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Arg9,
Arg10, Arg11, Arg12, Arg13, Arg14, Arg15, Arg16, Arg17, Arg18,
Arg19, Arg20, Arg21, Arg22, Arg23, Arg24, Arg25, Arg26, Arg27,
Arg28, Arg29, Arg30: OLEVariant) of object;

Use this event in order to pass parameters to the VBA procedure. Assign the parameters' values to ArgXX in strict order, otherwise you will get an exception. DataSource points to the instance of TxlDataSource corresponding to this event. If you make OnMacro event handler to be a common event handler for several instances of TxlDataSource class, you can use the Tag property of the class and AMacroName - the name of the VBA procedure to be invoked.

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