How can I convert excel file to pdf using C# winforms?

Question

Microsoft.Office.Interop.Excel.Application execl =
    new Microsoft.Office.Interop.Excel.Application();
       
        object oMissing = System.Reflection.Missing.Value;
        FileInfo execlFile = new FileInfo(txtNameFile.Text);
        execl.Visible = false;
        execl.ScreenUpdating = false;
        object filename = (object)execlFile.FullName;
        Workbook doc = execl.Workbooks.Open(ref filename, ref oMissing
            , ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing
            , ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing
            , ref oMissing, ref oMissing, ref oMissing, ref oMissing);
        doc.Activate();
        object outputFileName = execlFile.FullName.Replace(".Xls", ".pdf");
        object fileformat = WdSaveFormat.wdFormatPDF;
        doc.SaveAs2(ref outputFileName,
           ref fileformat, ref oMissing, ref oMissing
           , ref oMissing, ref oMissing, ref oMissing, ref oMissing
           , ref oMissing, ref oMissing, ref oMissing, ref oMissing
           , ref oMissing, ref oMissing, ref oMissing, ref oMissing);
        object savechanges = WdSaveOptions.wdSaveChanges;
        ((Workbooks)doc).Close(ref savechanges, ref oMissing, ref oMissing);
        doc = null;
        ((_Application)execl).Quit(ref oMissing, ref oMissing, ref oMissing);
        execl = null;
        MessageBox.Show("The File has been converted to PDF ");

Answer 1

Instead of saving with the SaveAs method, use the ExportAsFixedFormat method on the workbook for exporting to PDF format:

doc.ExportAsFixedFormat(Microsoft.Office.Interop.Excel.XlFixedFormatType.xlTypePDF, outputFileName);

Also, I would recommend against over-utilizing the object data type, which is a rather broad type. For instance, object outputFileName should be string outputFileName . It is easier for both the compiler and for other people reviewing your code if more specific data types are being used.