Export and Download multiple DataTables to CSV (Text) file in ASP.Net using C# and VB.Net

Hi Kani,

Check this example. Now please take its reference and correct your code.

For this i example i have refered the below articles. To create zip file you need DotNetZip Library which you can download from the below article.

1. Download multiple files as Zip Archive File in ASP.Net using C# and VB.Net
2. Export DataSet or DataTable to Word Excel PDF and CSV Formats

Namespaces

C#

using System;
using System.Collections.Generic;
using System.Data;
using System.Text;
using Ionic.Zip;

VB.Net

Imports System.Data
Imports Ionic.Zip

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    DataSet ds = new DataSet();
    DataTable dt1 = new DataTable();
    dt1.TableName = "Table1";
    dt1.Columns.AddRange(new DataColumn[3] { 
        new DataColumn("Id", typeof(int)),
        new DataColumn("Name", typeof(string)),
        new DataColumn("Country",typeof(string)) });
    dt1.Rows.Add(1, "John Hammond", "United States");
    dt1.Rows.Add(2, "Mudassar Khan", "India");
    dt1.Rows.Add(3, "Suzanne Mathews", "France");
    dt1.Rows.Add(4, "Robert Schidner", "Russia");

    DataTable dt2 = new DataTable();
    dt2.TableName = "Table2";
    dt2.Columns.AddRange(new DataColumn[3] { 
        new DataColumn("Id", typeof(int)),
        new DataColumn("Name", typeof(string)),
        new DataColumn("Country",typeof(string)) });
    dt2.Rows.Add(1, "Maria", "Austria");
    dt2.Rows.Add(2, "Thomas Hardy", "Ireland");
    dt2.Rows.Add(3, "Laurence Lebihan", "USA");
    dt2.Rows.Add(4, "Victoria Ashworth", "UK");

    ds.Tables.Add(dt1);
    ds.Tables.Add(dt2);
    List<Files> txtDatas = new List<Files>();
    foreach (DataTable dt in ds.Tables)
    {
        byte[] bytes = Encoding.ASCII.GetBytes(ConvertDataTableToString(dt));
        txtDatas.Add(new Files() { TableName = dt.TableName, Bytes = bytes });
    }

    using (ZipFile zip = new ZipFile())
    {
        zip.AlternateEncodingUsage = ZipOption.AsNecessary;
        foreach (Files txtData in txtDatas)
        {
            zip.AddEntry(txtData.TableName + ".csv", txtData.Bytes);
        }

        Response.Clear();
        Response.BufferOutput = false;
        string zipName = String.Format("Zip_{0}.zip", DateTime.Now.ToString("yyyy-MMM-dd-HHmmss"));
        Response.ContentType = "application/zip";
        Response.AddHeader("content-disposition", "attachment; filename=" + zipName);
        zip.Save(Response.OutputStream);
        Response.End();
    }
}

public static string ConvertDataTableToString(DataTable dt)
{
    StringBuilder sb = new StringBuilder();
    for (int k = 0; k < dt.Columns.Count; k++)
    {
        sb.Append(dt.Columns[k].ColumnName + ',');
    }
    sb.Append("\r\n");
    for (int i = 0; i < dt.Rows.Count; i++)
    {
        for (int k = 0; k < dt.Columns.Count; k++)
        {
            sb.Append(dt.Rows[i][k].ToString().Replace(",", ";") + ',');
        }
        sb.Append("\r\n");
    }

    return sb.ToString();
}

public class Files
{
    public string TableName { get; set; }
    public byte[] Bytes { get; set; }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    Dim ds As DataSet = New DataSet()
    Dim dt1 As DataTable = New DataTable()
    dt1.TableName = "Table1"
    dt1.Columns.AddRange(New DataColumn(2) {New DataColumn("Id", GetType(Integer)), _
                                            New DataColumn("Name", GetType(String)), _
                                            New DataColumn("Country", GetType(String))})
    dt1.Rows.Add(1, "John Hammond", "United States")
    dt1.Rows.Add(2, "Mudassar Khan", "India")
    dt1.Rows.Add(3, "Suzanne Mathews", "France")
    dt1.Rows.Add(4, "Robert Schidner", "Russia")
    Dim dt2 As DataTable = New DataTable()
    dt2.TableName = "Table2"
    dt2.Columns.AddRange(New DataColumn(2) {New DataColumn("Id", GetType(Integer)), _
                                            New DataColumn("Name", GetType(String)), _
                                            New DataColumn("Country", GetType(String))})
    dt2.Rows.Add(1, "Maria", "Austria")
    dt2.Rows.Add(2, "Thomas Hardy", "Ireland")
    dt2.Rows.Add(3, "Laurence Lebihan", "USA")
    dt2.Rows.Add(4, "Victoria Ashworth", "UK")
    ds.Tables.Add(dt1)
    ds.Tables.Add(dt2)
    Dim txtDatas As List(Of Files) = New List(Of Files)()
    For Each dt As DataTable In ds.Tables
        Dim bytes As Byte() = Encoding.ASCII.GetBytes(ConvertDataTableToString(dt))
        txtDatas.Add(New Files() With {.TableName = dt.TableName, .Bytes = bytes})
    Next

    Using zip As ZipFile = New ZipFile()
        zip.AlternateEncodingUsage = ZipOption.AsNecessary
        For Each txtData As Files In txtDatas
            zip.AddEntry(txtData.TableName & ".csv", txtData.Bytes)
        Next

        Response.Clear()
        Response.BufferOutput = False
        Dim zipName As String = String.Format("Zip_{0}.zip", DateTime.Now.ToString("yyyy-MMM-dd-HHmmss"))
        Response.ContentType = "application/zip"
        Response.AddHeader("content-disposition", "attachment; filename=" & zipName)
        zip.Save(Response.OutputStream)
        Response.[End]()
    End Using
End Sub

Public Shared Function ConvertDataTableToString(ByVal dt As DataTable) As String
    Dim sb As StringBuilder = New StringBuilder()
    For k As Integer = 0 To dt.Columns.Count - 1
        sb.Append(dt.Columns(k).ColumnName + ","c)
    Next

    sb.Append(vbCrLf)
    For i As Integer = 0 To dt.Rows.Count - 1
        For k As Integer = 0 To dt.Columns.Count - 1
            sb.Append(dt.Rows(i)(k).ToString().Replace(",", ";") + ","c)
        Next

        sb.Append(vbCrLf)
    Next

    Return sb.ToString()
End Function

Public Class Files
    Public Property TableName As String
    Public Property Bytes As Byte()
End Class

Output

Each DataTable will be saved with .csv extension inside the zip file.