I've been reading through:

https://www.aspsnippets.com/Articles/Export-data-from-SQL-Server-to-CSV-file-in-ASPNet-using-C-and-VBNet.aspx

Rather than only have the option to download as csv as described there in:

                //Download the CSV file.
                Response.Clear();
                Response.Buffer = true;
                Response.AddHeader("content-disposition", "attachment;filename=SqlExport.csv");
                Response.Charset = "";
                Response.ContentType = "application/text";
                Response.Output.Write(csv);
                Response.Flush();
                Response.End();

is there a way using native asp.net to first zip the csv output from the csv variable in Response.Output.Write(csv); so that the user downloads SqlExport.zip rather than SqlExport.csv?

CodePudding user response：

Roughly based on this, you can create a zip file while streaming it to the client;

Response.ContentType = "application/octet-stream";
Response.Headers.Add("Content-Disposition", "attachment; filename=\"SqlExport.zip\"");

using var archive = new ZipArchive(Response.Body, ZipArchiveMode.Create);

var entry = archive.CreateEntry("SqlExport.csv");
using var entryStream = entry.Open();

entryStream.Write(csv); // write the actual content here

entryStream.Flush();

Though rather than appending to a single csv string, you should probably consider using a StreamWriter to write each snippet of text directly into the response stream. Substituting from your linked csv example;

using var sw = new StreamWriter(entryStream);

// TODO write header

foreach (DataRow row in dt.Rows)
{
    foreach (DataColumn column in dt.Columns)
    {
        //Add the Data rows.
        await sw.WriteAsync(row[column.ColumnName].ToString().Replace(",", ";")   ',');
    }
    //Add new line.
    await sw.WriteLineAsync();
}

Though that is a terrible example of a csv file. Rather than substituting ';' characters, the string should be quoted & all quotes escaped.

CodePudding user response：

Have a look at the ZipArchive Class

you can use public System.IO.Compression.ZipArchiveEntry CreateEntry (string entryName); to create an ZipEntry nd add it to an archive