From 4eaf806c4e64bcabc762517e07001886efde4611 Mon Sep 17 00:00:00 2001
From: HLWeil <hl.weil@t-online.de>
Date: Mon, 12 Feb 2024 12:31:00 +0100
Subject: [PATCH] add fail for writing empty workbook #38

---
 src/FsSpreadsheet.ExcelIO/FsExtensions.fs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/FsSpreadsheet.ExcelIO/FsExtensions.fs b/src/FsSpreadsheet.ExcelIO/FsExtensions.fs
index 70d3eaca..4c625679 100644
--- a/src/FsSpreadsheet.ExcelIO/FsExtensions.fs
+++ b/src/FsSpreadsheet.ExcelIO/FsExtensions.fs
@@ -335,8 +335,10 @@ module FsExtensions =
         /// Writes the FsWorkbook into a given MemoryStream.
         /// </summary>
         member self.ToStream(stream : MemoryStream) = 
+            if self.GetWorksheets() |> Seq.isEmpty then
+                failwith "Cannot write an empty workbook to a stream. Workbook did not contain any Worksheets."
             let doc = Spreadsheet.initEmptyOnStream stream 
-
+            
             self.ToEmptySpreadsheet(doc)
                 //Worksheet.setSheetData sheetData sheet |> ignore
                 //WorkbookPart.appendWorksheet worksheet.Name sheet workbookPart |> ignore