Hi,
Can you try the following sample using ClosedXML?
Sample20230930-1aL_Windows.zip (11.6 KB)
Using wb As New ClosedXML.Excel.XLWorkbook(filename)
Dim sheet As ClosedXML.Excel.IXLWorksheet = wb.Worksheet(sheetName)
With sheet.Range(strRange).Style
.Border.SetTopBorder(CLosedXML.Excel.XLBorderStyleValues.Thin)
.Border.SetBottomBorder(CLosedXML.Excel.XLBorderStyleValues.Thin)
.Border.SetLeftBorder(CLosedXML.Excel.XLBorderStyleValues.Thin)
.Border.SetRightBorder(CLosedXML.Excel.XLBorderStyleValues.Thin)
End With
wb.Save()
End Using
Regards,