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Bug 832
| Summary: | Trouble writing chart and restoring it when simple functions are used | ||
|---|---|---|---|
| Product: | VCL TeeChart | Reporter: | h.hasenack <hans> |
| Component: | Chart | Assignee: | Steema Issue Manager <issuemanager> |
| Status: | RESOLVED FIXED | ||
| Severity: | critical | CC: | david, marc, sandra |
| Priority: | High | ||
| Version: | unspecified | ||
| Target Milestone: | --- | ||
| Hardware: | PC | ||
| OS: | Windows | ||
| Chart Series: | --- | Delphi / C++ Builder RAD IDE Version: | |
| Attachments: | Reproduceable Test case | ||
Many thanks for your fix. We will review it for inclusion in our source code for future maintenance releases. Created attachment 268 [details]
Reproduceable Test case
Small project to reproduce stream writing/reading a Chart with Series/TeeFunction and DataSource.
One solution to this problem is using a TWriter object.
In the attached project, the "Stream" button does not work, and the "Writer" button works.
Setting TWriter Root property to the owner of the datasource (the Form1), stores the datasource component name without the Form prefix, so it can be reloaded correctly:
s:=TMemoryStream.Create;
try
w:=TWriter.Create(s,8192);
try
w.WriteSignature;
w.Root:=Self; <----------------- Form1
w.WriteComponent(Chart1);
finally
w.Free;
end;
I believe my solution using the component name and the afterwards resolver is a better solution. If the code soent break anything, could you please add it to the next teechart release? Thx slow to get here but code added. Thx for the feedback. |
simple functions with single datasources lose their datasource when the chart is written using TStream.WriteObjectResource and later reloading it. This is because of the 'Datasources' defineproiperties implementation and the IsDataSourceStored implementation. When only 1 datasource is present, it is stored using a component link instead of a component name (like de datasources list). When the chart is reloaded later on, the series get to be owned by the chart rather than the form containg the chart causing the single datsource link not be resolved. I have created a solution and verified that it works in my case. It is not likely to break any existing code, so here it is. IMHO it could be even fixed a bit better if the .Loaded routine that resolves the FTempDatasourcesList would be a bit more intelligent. To me the issue is critical since it blocks storing and restoring charts defined /adjusted by my users. Here are my patches for teengine.pas: procedure TChartSeries.DefineProperties(Filer: TFiler); begin inherited; Filer.DefineProperty('DataSources',ReadDataSources,WriteDataSources, Assigned(FDataSources) {$ifdef HH_PATCH_TC_DATASOURCEPERSISTANCE} and (FDataSources.Count>0) and not IsDataSourceStored {$else} and (FDataSources.Count>1) {$endif} ); { <-- don't translate } Filer.DefineProperty('CustomHorizAxis', ReadCustomHorizAxis, WriteCustomHorizAxis,Assigned(FCustomHorizAxis)); { <-- don't translate } Filer.DefineProperty('CustomVertAxis', ReadCustomVertAxis, WriteCustomVertAxis,Assigned(FCustomVertAxis)); { <-- don't translate } Filer.DefineBinaryProperty('Data',ReadData,WriteData,IsDataStored); end; Function TChartSeries.IsDataSourceStored:Boolean; Begin {$ifdef HH_PATCH_TC_DATASOURCEPERSISTANCE} // chart custom elements always through Datasources property (linked by component name) result:=(DataSources.Count=1) and not (Datasources[0] is TCustomChartElement); {$else} result:=DataSources.Count=1;; {$endif} end;