How can I send an Excel file by email?

Question

I have an excel file (Excel 2003 / xls format) and I want to send it by email with c#. My code send it successfully, but when I try to open the response file, it seems to encoded wrongly.

For example here is the response filename:

=_utf-8_B_RWxzesOhbW9sw6FzXzIwMTJfMTBfMTZf.dat

And here is the response file itself:

=?utf-8?B?VEdWdmJIWmhjMkZ1Wk1Pelh6UXlYekZmPz0NCiA9P3V0Zi04P0I/VGtW?=\ \ =?utf-8?B?TlgwZFRXaTU0YkhNPT89?=" Content-Transfer-Encoding: base64 Content-Disposition: attachment

0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAAAAAABAAAA AQAAAAAAAAAAEAAAIwAAAAEAAAD+////AAAAAAAAAAD///////////////////// //////////////////////////////////////////////////////////////// ////////////////////////////// ....

Here is my code fragment:

...
var attachment = new Attachment(WriteFileToMemory("fileFullPath"), "fileName.xls");
attachment.ContentType = new ContentType("application/vnd.ms-excel");
attachmentCollection.Add(attachment);
...


private Stream WriteFileToMemory(string filePath)
{
    var memoryStream = new MemoryStream();
    _openedStreams.Add(memoryStream);
    using (var file = new FileStream(filePath, FileMode.Open, FileAccess.Read))
    {
        var bytes = new byte[file.Length];
        file.Read(bytes, 0, (int) file.Length);
        memoryStream.Write(bytes, 0, (int) file.Length);
        file.Close();
    }
    memoryStream.Position = 0;
    return memoryStream;
}

How can I set the attachment encoding type, and which encoding should I use with Excel files?

Please help me solve this problem. Thanks in advance.

Answer 1

You are making it too complex, as @Magnus points out, new Attachment() can handle FileStreams so just pass a new filestream to the constructor.

...
var attachment = new Attachment(File.Open("fileFullPath", FileMode.Open), "fileName.xls");
attachment.ContentType = new ContentType("application/vnd.ms-excel");
attachmentCollection.Add(attachment);
...

A word of warning though, kind is off topic, you cannot send a mail like that multiple times since the stream will not always reset itself properly.

Answer 2

In case you want to generate Excel from a DataTable, and send it by mail, you can attach the excel file as follows:

Workbook theWorkbook = new Workbook();
theWorkbook.SetCurrentFormat(WorkbookFormat.Excel2007);
Worksheet theWorkSheet = theWorkbook.Worksheets.Add("Sheet1");

int iRow = 0;
int iColumn = 0;
theWorkSheet.Rows[0].CellFormat.Font.Bold = ExcelDefaultableBoolean.True;

//Titles
foreach (DataColumn column in DataTable.Columns)
{
    theWorkSheet.Rows[iRow].Cells[iColumn].Value = column.ColumnName;
    iColumn++;
}

//Values
foreach (DataRow row in DataTable.Rows)
{
    iColumn = 0;
    iRow++;

    foreach (var item in row.ItemArray)
    {
        theWorkSheet.Rows[iRow].Cells[iColumn].Value = item.ToString();
        iColumn++;
    }                    
}
System.IO.MemoryStream theStream = new System.IO.MemoryStream();
theWorkbook.Save(theStream);
byte[] byteArr = theStream.ToArray();
System.IO.MemoryStream stream1 = new System.IO.MemoryStream(byteArr, true);
stream1.Write(byteArr, 0, byteArr.Length);
stream1.Position = 0;
message.Attachments.Add(new Attachment(stream1, "filename.xlsx"));

It worked for me at least with .NET framework 4 and Excel 2016.

Regards.