I am using the latest Microsoft.Office.Interop.Excel dll
The system currently saves the file in .xls format.
I have used the following code but I am getting an error.
App = CreateObject("Excel.Application")
xlsTemplate= App.Workbooks.Open(TemplateFile) ' template is in .xls format
TargetPath = Some target path.xlsx
Excel.Workbook.SaveCopyAs(TargetPath)
Excel.Workbook = App.Workbooks.Open(TargetPath) ' code breaks here
SomeFunction(Excel.Workbook)
ExcelBook.SaveAs(ExcelBook.FullName, Microsoft.Office.Interop.Excel.XlFileFormat.xlOpenXMLWorkbook, System.Reflection.Missing.Value, System.Reflection.Missing.Value, False, False, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange, Microsoft.Office.Interop.Excel.XlSaveConflictResolution.xlUserResolution, True, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value)
ExcelBook.Saved = True
Error:Excel cannot open the file '.xlsx' because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.
I am responding to this thread as current answers were unclear to me - which forced me to do more research.
Changing the extension in the name does not change the file format. To save the excel document in your desired format use the below parameters within your Microsoft.Office.Interop.Excel to save your workbook (VB.NET):
wb.SaveAs("C:\MyFolder\MyWorkbook.xlsx",XlFileFormat.xlOpenXMLWorkbook)
You can modify the second parameter (File Format) to specify what version you want to save the document.