In Excel formulas, the double minus (--) is known as the "double unary operator." Its main purpose is to convert Boolean values (TRUE/FALSE) into numeric values (1/0).
How it works:
• TRUE becomes 1
• FALSE becomes 0
Example: Suppose you have an array formula like:
=SUM(--(B2:B20="Gamma"))
• (B2:B20="Gamma") produces an array of TRUE/FALSE.
• --(B2:B20="Gamma") converts that array to 1/0.
• SUM(...) then adds up the number of matches.
Some Excel functions (like SUM, SUMPRODUCT) require numbers, not Booleans.
The double unary is a concise way to force this conversion.
SEARCH function with the following format is valid only in Excel 365/2021 or later (with dynamic array support).
"=SEARCH({"Alpha","Beta","Gamma","Delta","Omega","Sigma","Zeta"}, "Omega")"
• It returns an array of numbers or errors, showing the position of each substring in "Omega".
• If a substring is found, you get its position (e.g., 1 for "Omega"); if not, you get #VALUE!.
Cached formula values are not respected for the AdditionExpression type.
GetResultValueAsString returns "#NAME?".
Here are the steps:
1. Copy some basic content from Excel (two text cells)
2. Paste the content to the Telerik Blazor Spreadsheet component and save the XLSX file
3. Try importing this file with RadSpreadProcessing
at System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument) at System.Collections.Generic.Dictionary`2.FindValue(TKey key) at System.Collections.Generic.Dictionary`2.ContainsKey(TKey key) at Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.Model.Elements.Worksheets.ConditionalFormattingRuleElementX14.OnAfterRead(IXlsxWorksheetImportContext context) in C:\Work\document-processing\Documents\Spreadsheet\FormatProviders\OpenXml\Xlsx\Model\Elements\Worksheets\ConditionalFormatting\x14\ConditionalFormattingRuleElementX14.cs:line 62
The COUNTA function counts cells containing any type of information, including error values and empty text ("")
https://support.microsoft.com/en-us/office/counta-function-7dc98875-d5c1-46f1-9a82-53f3219e2509
string inputFileName = "input.xlsx";
if (!File.Exists(inputFileName))
{
throw new FileNotFoundException(String.Format("File {0} was not found!", inputFileName));
}
Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook;
IWorkbookFormatProvider formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider();
using (Stream input = new FileStream(inputFileName, FileMode.Open))
{
workbook = formatProvider.Import(input, TimeSpan.MaxValue);
}
string outputFilePath = "output.xlsx";
using (Stream output = new FileStream(outputFilePath, FileMode.Create))
{
formatProvider.Export(workbook, output, TimeSpan.MaxValue);
}
Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });
Incorrect timestamp of a DateTime with custom number format.
Expected:
Actual:
Apply Note style:
Set None Fill:
trying to open the attached workbook with this code:
Telerik.Windows.Documents.Spreadsheet.Model.Workbook workbook;
using (Stream input = File.OpenRead("sample.xlsx"))
{
var provider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider();
// The import method enables you to also pass a byte[] with the XLSX document data
workbook = provider.Import(input, TimeSpan.FromSeconds(30));
}
I get an unhandled exception:
An unhandled exception of type 'System.ArgumentNullException' occurred in Telerik.Documents.Spreadsheet.dll
Value cannot be null.
Any idea what's going on?
Thank you for your time,
Phil