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how can we avoid readonly of the excel file during the writestream to excel from c# , if the excel file is open?

Posted by: admin April 23, 2020 Leave a comment


during writing values to an excel from c#, at the same time the excel file is open it shows the error that the file is in readonly , so how can we able to avoid that error during write stream from c# to the Excel

    //Get all the sheets in the workbook
 mWorkSheets = mWorkBook.Worksheets;
 //Get the allready exists sheet
 mWSheet1 = (Microsoft.Office.Interop.Excel.Worksheet)mWorkSheets.get_Item("Sheet1");
 Microsoft.Office.Interop.Excel.Range range = mWSheet1.UsedRange;

 int colCount = range.Columns.Count;

 int rowCount = range.Rows.Count+1;
 for (int index = 0; index < NoOfRecords; index++)
     for (int j = 0; j < colCount; j++)
         mWSheet1.Cells[(rowCount) + index, j + 1] ="'"+Convert.ToString(ResultsData.Rows[index][j].ToString());

 mWorkBook.SaveAs(path, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,
 Missing.Value, Missing.Value, Missing.Value, Missing.Value, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,
 Missing.Value, Missing.Value, Missing.Value,
 Missing.Value, Missing.Value);
mWorkBook.Close(Missing.Value, Missing.Value, Missing.Value);
How to&Answers:

The easiest way is to SAVEAS to a different file name, then delete the original file on successful save. Like open MySheet.XLSX and save MySheet_Updated.XLSX

 string newPath = path.Replace(Path.GetFileNameWithoutExtension(path),Path.GetFileNameWithoutExtension(path)+"_Updated)";
    mWorkBook.SaveAs(newPath,Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,Missing.Value,Missing.Value,Missing.Value,Missing.Value,Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,Missing.Value,Missing.Value,Missing.Value,Missing.Value, Missing.Value);
   mWorkBook.Close(Missing.Value, Missing.Value, Missing.Value);
 catch(Exception e){


    public System.Data.DataTable CorruptedExcel(string path, string savedFile) {
        Missing missing = Missing.Value;
       Excel.Application excel = new Excel.Application();

       Microsoft.Office.Interop.Excel.Workbook workbook = excel.Workbooks.Open(path, CorruptLoad: Microsoft.Office.Interop.Excel.XlCorruptLoad.xlRepairFile);

        var connectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=YES;TypeGuessRows=0;ImportMixedTypes=Text\"";
        //var connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;IMEX=1;HDR=NO;TypeGuessRows=0;ImportMixedTypes=Text\""; ;
        using (var conn = new OleDbConnection(connectionString))


            var sheets = conn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
            using (var cmd = conn.CreateCommand())
                cmd.CommandText = "SELECT * FROM [" + sheets.Rows[0]["TABLE_NAME"].ToString() + "] ";

                var adapter = new OleDbDataAdapter(cmd);


        return dt;
    catch (Exception e)
        throw new Exception("ReadingExcel: Excel file could not be read! Check filepath.\n"
            + e.Message + e.StackTrace);