Create API allowing conversion of .NET standard numeric format strings to Excel/RadSpreadsheet's number formats.

For example, G3 .NET numeric format should be converted to scientific notation RadSpreadsheet mode - CellValueFormat("0.00E+00").

Introduce support for cell reference ranges which refer to whole columns. For example "=Sheet1$A:$A" refers to the whole column A.

A reference that refers to the same cell or range on multiple sheets. 

Example: =SUM(Den1:Den31!C10) will sum C10 from all sheets between Den1 and Den3.

When defaultThemeVersion is missing from the file, some styles are not shown when the document is opened in MS Excel.

The value of Worksheet.UsedCellRange could be calculated during the import of the workbook - as all cells are processed anyway. This will improve the performance of the first usage of this property, which is very common scenario. Also xlsx documents can have optional 'dimension' element which is used to specify the used cell range:

<dimension ref="A1:C2"/>.

Some functions are exported from Excel with the _xlfn. prefix as compatibility measure with older versions of MS Excel (future functions, see here https://msdn.microsoft.com/en-us/library/dd907480(v=office.12).aspx , https://support.office.com/en-ca/article/Issue-An-xlfn-prefix-is-displayed-in-front-of-a-formula-882f1ef7-68fb-4fcd-8d54-9fbb77fd5025 )

RadSpreadProcessing do not support these and the spreadsheet treats the function as not supported even when it is.

Example:

    <row r="1" spans="2:2" x14ac:dyDescent="0.25">
      <c r="B1" t="b">
        <f>_xlfn.ISFORMULA(C2)</f>
        <v>0</v>
      </c>
    </row>


This could be observed with the ISFORMULA function.

Now there is no public API that allows the users to check if a Worksheet is empty or not. The UsedCellRange property returns a cell range that is only the cell A1 even if it is empty too.

Possible solution is to expose IsEmpty property of the CellRange.

Workaround: Check if Worksheet.UsedCellRange contains only A1, and that additionally A1 is empty.

When I need to populate a cell that I find using a DefinedName  I should parse RefersTo to get Worksheet name. But DefinedName class contains Scope property which has  CurrentWorksheet and Workbook properties (internal). It would be very useful if these properties could be public.

Add API to get the list of ranges to which a defined name refers.

Example:
List<CellRange> ranges = workbook.Names["definedName"].Ranges;
CellSelection selection = worksheet.Cells[ranges];

The cell range referred by the defined name could be accessed using code similar to the following one:
foreach (var name in workbook.Names)
{
    if (name.Name == givenName)
    {
        string[] v = name.RefersTo.Split("!".ToCharArray());

        foreach (Worksheet sheet in workbook.Sheets)
        {
            if (sheet.Name.ToUpper() == v[0].Replace("=", String.Empty).ToUpper())
            {
                string rangeName = v[1];
                string firstIndexName = rangeName.Split(":".ToCharArray())[0];

                int rowIndex;
                int columnIndex;
                bool isRowAbsolute;
                bool isColumnAbsolute;
                bool nameRefersToIndex = NameConverter.TryConvertCellNameToIndex(firstIndexName, out isRowAbsolute, out rowIndex, out isColumnAbsolute, out columnIndex);

                if (nameRefersToIndex)
                {
                    sheet.Cells[rowIndex, columnIndex].SetValue(givenValue);
                }
            }
        }
    }
}

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

Add support for the SUBTOTAL function: https://support.office.com/en-us/article/SUBTOTAL-function-7b027003-f060-4ade-9040-e478765b9939

It computes the subtotal for some ranges, given the code for the subtotal function:

SUBTOTAL(function_num,ref1,[ref2],...)

where function_num is code referring to some of the functions: AVERAGE, COUNT, COUNTA, MAX, MIN, PRODUCT, STDEV, STDEVP, SUM, VAR, VARP.

Note that we should implement the support for all of the above functions. As of now, COUNTA, VAR, VARP are not supported.

Workaround: This could be implemented as a custom function: http://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formulas/custom-functions.html , but multiple functions (4 as of now) has to be additionally implemented.

Add support for ROW function: https://support.office.com/en-us/article/ROW-function-3a63b74a-c4d0-4093-b49a-e76eb49a6d8d?ui=en-US&rs=en-US&ad=US

Examples:

=ROW() returns the row in which the formula appears
=ROW(C10) returns the row of the reference - 10


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

Implement SMALL function (https://support.office.com/en-us/article/SMALL-function-17da8222-7c82-42b2-961b-14c45384df07 ), which returns k-th smallest value from a range:

SMALL(array, k)

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

The MATCH function searches for a specified item in a range of cells and returns the relative position of the item found in this range.

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 R3 2017 Official Release Version

An InvalidOperationException could be thrown in multi-threaded export to XLSX format. However, the problem is not verified.

Here is the stacktrace:

ERROR System.InvalidOperationException: isParsing must be true.
   at Telerik.Windows.Documents.Spreadsheet.Utilities.Guard.ThrowExceptionIfTrue(Boolean param, String paramName)
   at Telerik.Windows.Documents.Spreadsheet.Model.Printing.HeaderFooterSectionTextParser.OnBeforeParse(String headerFooterSectionText)
   at Telerik.Windows.Documents.Spreadsheet.Model.Printing.HeaderFooterSectionTextParser.Parse(String headerFooterSectionText)
   at Telerik.Windows.Documents.Spreadsheet.Model.Printing.HeaderFooterSectionTextSanitizer.Sanitize(String sectionText)
   at Telerik.Windows.Documents.Spreadsheet.Model.Printing.HeaderFooterContent.BuildContentText()
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.Model.Elements.Worksheets.HeaderFooterElement.WriteChild[T](OpenXmlChildElement`1 child, HeaderFooterContent content)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.Model.Elements.Worksheets.HeaderFooterElement.WriteChildren(HeaderFooterSettings settings)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.Model.Elements.Worksheets.HeaderFooterElement.OnBeforeWrite(IXlsxWorksheetExportContext context)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.Model.Elements.Worksheets.WorksheetElementBase.OnBeforeWrite(IXlsxWorkbookExportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase`3.OnBeforeWrite(IOpenXmlExportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Write(IOpenXmlWriter writer, IOpenXmlExportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Write(IOpenXmlWriter writer, IOpenXmlExportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Parts.OpenXmlPartBase.Export(IOpenXmlWriter writer, IOpenXmlExportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Export.OpenXmlExporter`2.ExportPart(OpenXmlPartBase part, TContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Export.OpenXmlExporter`2.Export(Stream output, TContext context, OpenXmlExportSettings settings)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider.ExportOverride(Workbook workbook, Stream output)
   at Telerik.Windows.Documents.Spreadsheet.FormatProviders.WorkbookFormatProviderBase.Export(Workbook workbook, Stream output)

Available in LIB Version 2017.2.828.

There are scenarios when the default value of the columns is changed and may be different from 65. However, RadSpreadprocessing always exports the non-custom column values as 65.

WORKAROUND: After importing the XLSX file you may make all columns to have custom values in order to preserve the column widths after the export. The following code snippet shows how this may be achieved for some Worksheet instance:

CellRange usedRange = worksheet.UsedCellRange;

for (int i = 0; i < usedRange.ColumnCount; i++)
{
    ColumnSelection column = worksheet.Columns[i];
    double width = column.GetWidth().Value.Value;
    column.SetWidth(new ColumnWidth(width, true));
}

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

Comparison operators (equal '=', not equal '<>') doesn't work as expected with references to empty cells. For example, expressions of type '=IF(A1="", TRUE, FALSE)' are evaluated to false when A1 cell is empty. 

In MS Excel, such expression is evaluated to TRUE if the cell is empty - i.e. empty cell value is considered equal to an empty string "".

Workaround: Use ISBLANK function if possible. Its results are consistent with MS Excel.