Fixes

• Workbook_Open — file branch left junk files and locked them.
  File.Open(path, FileMode.OpenOrCreate) silently created a 0-byte file on a typo'd path (then EPPlus failed with a cryptic "central directory not found"), and the FileStream was never disposed, so the file stayed locked by the app-pool process until GC.
  Now uses FileMode.Open / FileAccess.Read / FileShare.Read and disposes the stream via using.

• ConditionalFormatting_DeleteRule deleted the wrong rule.
  The guard requires index >= 1, but ExcelConditionalFormattingCollection.RemoveAt(...) is a standard 0-based collection. So the first rule could never be deleted (it would remove rule 2), and every other index was off by one. 

• Cell_WriteImageByIndex / Cell_WriteImageByName placed the image one cell down-right.
  EPPlus's ExcelPicture.SetPosition(row, …, col, …) takes a 0-based anchor. The wrapper passed the OutSystems 1-based row/column raw, so writing to A4 actually landed at B5. Image_Insert already converted correctly (range.Start.Row - 1); this brings the two image actions in line.

• Minor cleanup: stray double semicolon in Column_Hide_Show and a dead STDataSeriesStructure curr_series local in Chart_Create.

Fixes

• MssCell_WriteImageByIndex – leaked image handles. The Image and MemoryStream were never disposed (a leak on every call). They are now wrapped in using blocks.

• MssWorksheet_GetImages – images were always re-encoded as GIF. Util.ImageToByteArray saved every image as GIF regardless of the original format (lossy, wrong type). It now preserves the original format, falling back to PNG for formats that cannot be written directly.

Added the Chart_Create action which allows for creation of charts in a specific worksheet. 

Define the ranges of cells from which you want to feed your series into the chart and choose from a number of types by passing in the name of the type.

Check out an example here:

https://www.outsystems.com/forums/discussion/36870/advanced-excel-chart-creation-example/

A new action has been added to the "Advanced Excel" extension called “Workbook_AddOsDbSheet”.

This action will need a few input parameters, like the WorkbookInObj, the WorksheetName, the OsDbDataSet, the RowStart, the ColumStart and IncludingHeader.

When this action is used for the first time in a row, the WorkbookInObj  should be nullObject().

In that case the action will automatically open a workbook object, which reference will be returned via WorkbookOutObj afterwards.

The next time the action is used the WorkbookInObj will be populated with the previous WorkbookOutObj reference. The use of the other fields is clear, I guess.

• Fixed a bug in Cell_WriteByIndex function;
• Added function Worksheet_GetName that returns, as text, the name of the worksheet provided;
• Added function Worksheet_DeleteByIndex to delete sheets by index;
• Added function Worksheet_DeleteByName to delete sheets by name;
• Added function WorkBook_AddSheet to add new sheets by name;
• Added function Cell_MergeRange to merge multiple cells.

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