Add API for registering custom image decoders, e.g. for .emf and .wmf images.

Add support for the AVERAGEIF function:  https://support.office.com/en-us/article/AVERAGEIF-function-faec8e2e-0dec-4308-af69-f5576d8ac642

Returns the average (arithmetic mean) of all the cells in a range that meet a given criteria:

AVERAGEIF(range, criteria, [average_range])


Workaround: This could be implemented as a custom function: http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions.html

The exception is thrown when importing a document that contains an empty stylesheet tag in its styles.xml part.

For example, if a user wants to set a 5x5 array of values in the worksheet he has to iterate through all the values one by one and set it to the worksheet. With that API the user should be able to set the entire array with just one method call giving it the array.

When calling AutoFitWidth on single cell selections there is no issue. However, calling it on a multi-column selection the document is corrupted and repair error message is shown when opening it in Excel.

Workaround: The AutoFitWidth method may be called for each column separately. 

If Spreadsheet's history is not enabled, merged cells cannot be unmerged. 

Workaround: Enable the History before calling Unmerge():

workbook.History.IsEnabled = true;
worksheet.Cells[0, 0, 0, 4].Unmerge();
workbook.History.IsEnabled = false;

This would allow repeating header rows on every printed page. More information related to this functionality may be found on the following link:

https://support.office.com/en-us/article/Print-rows-with-column-headers-on-top-of-every-page-d3550133-f6a1-4c72-ad70-5309a2e8fe8c

Add support for TRIM function. TRIM removes all spaces from text except for single spaces between words.

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/CustomFunctions

Available in R2 2017 Official Release.

Add support for CHOOSE function. CHOOSE uses the number parameter to return a value from the list of value arguments. 

A list of the supported functions is available at http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/functions

This function can be implemented as a custom function. Check the following resources for more details on how to achieve that:

- http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions
- https://github.com/telerik/xaml-sdk/tree/master/Spreadsheet/CustomFunctions

Available in R2 2017 Official Release.

When the default number formats for Accounting and Currency are used and the current culture is Russian, the number format is not parsed correctly.

For instance, when exporting FLOOR.MATH function a #NAME error is displayed initially.

Workaround: Select the cell in Excel, click in the formula bar and press Enter without changing anything. This fixes the #NAME error and Excel manages to successfully display the function result.

When there are split panes in a workbook, the topLeftCell property can be omitted. In this case, the format provider throws NullReferenceException.

Add support for superscript and subscript font effects for cell formatting. Currently, this is not supported by the model and is omitted on import.

Excel exports shapes as TwoCellAnchor elements, which specifies the top left and the bottom right location of a shape. The size of the shape is recorded in the extents element (a:ext), cx and cy attributes. At the moment, the spreadsheet import first looks at the extents element and if it doesn't find the size there, calculates it from the TwoCellAnchor element. 

However, if an XLSX document has a shape with incorrect size indicated in the extents element, Excel will still be able to open it correctly, probably because it looks at the TwoCellAnchor element. RadSpreadsheet/SpreadProcessing, on the other hand, will show the image with an incorrect size.

The ADDRESS function is used to obtain the address of a cell in a worksheet, given specified row and column numbers. For example, ADDRESS(2,3) returns $C$2.

KeyNotFoundException is thrown on import. The number formats with id 5, 6, 7 and 8 are missing in the built-in number formats.

Available in R2 2018 Official Release version.

When the values that were copied have formatting both on the cell and on the column, the pasted values get the formatting of the column, instead of that of the cell. The same applies to rows.

The named ranges need to be translated when used in a certain cell just like the data validation rules.

WORKAROUND: When you use RowSelection.Insert() method, for instance, after the row insertion you may iterate all defined names in the document. Parse their RefersTo property and if it is affected by the insertion, delete and recreate the DefinedName in the corresponding NameCollection by updating the RefersTo text value. Sample code for parsing the RefersTo property may be seen in the description of this feedback item: 

https://feedback.telerik.com/Project/184/Feedback/Details/190061-spreadprocessing-add-api-to-get-the-list-of-ranges-to-which-a-defined-name-refer

When the worksheet contains many formulas which use large ranges (e.g. covering 50000 cells) as arguments and these formulas have to be calculated, this causes OutOfMemoryException. 

The format string for dates should be in lowercase so they can work as expected. Ensure this in the internal logic.