In this article I will explain with an example, how to download CSV file from Database in ASP.Net MVC.
Note: For beginners in ASP.Net MVC, please refer my article ASP.Net MVC Hello World Tutorial with Sample Program example.
 
 

Database

I have made use of the following table tblFiles with the schema as follow.
Download CSV file from Database in ASP.Net MVC
 
I have already inserted few records in the table.
Download CSV file from Database in ASP.Net MVC
 
Note: You can download the database table SQL by clicking the download link below.
            Download SQL file
 
 

Model

The Model class consists of the following properties.
public class FileModel
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string ContentType { get; set; }
    public byte[] Data { get; set; }
}
 
 

Namespaces

You will need to import the following namespaces.
using System.Data.SqlClient;
using System.Configuration;
 
 

Controller

The Controller consists of following Action methods.

Action method for handling GET operation

Inside this Action method, the GetFiles method is called.
Inside the GetFiles method, the records from the tblFiles table are fetched using DataReader and Generic List of FileModel class objects is populated.
Finally, the Generic List of FileModel class objects is returned to the View.
 

Action method for handling POST operation for downloading Files

When the Download link inside the HTML Table (Grid) is clicked, the Id of the particular file is sent to this Action method and using the File Id, the File’s binary data is fetched from the database using ADO.Net.
Note: The following Action method performs File Download and hence the return type is set to FileResult.
 
Finally, the File is downloaded using the File function.
public class HomeController : Controller
{
    // GET: Home
    public ActionResult Index()
    {
        return View(GetFiles());
    }
 
    [HttpPost]
    public FileResult DownloadFile(int? fileId)
    {
        byte[] bytes;
        string fileName, contentType;
        string sql = "SELECT Name, Data, ContentType FROM tblFiles WHERE Id=@Id";
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                cmd.Parameters.AddWithValue("@Id", fileId);
                con.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    sdr.Read();
                    bytes = (byte[])sdr["Data"];
                    contentType  = sdr["ContentType"].ToString();
                    fileName = sdr["Name"].ToString();
                }
                con.Close();
            }
        }
 
        return File(bytes, contentType, fileName);
    }
 
    private static List<FileModel>GetFiles()
    {
        List<FileModel> files = new List<FileModel>();
        string sql = "SELECT Id, Name FROM tblFiles";
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                con.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {
                        files.Add(new FileModel
                        {
                             Id = Convert.ToInt32(sdr["Id"]),
                             Name = sdr["Name"].ToString()
                        });
                    }
                }
                con.Close();
            }
        }
        return files;
    }
}
 
 

View

HTML Markup

Inside the View, in the very first line the FileModel class is declared as IEnumerable which specifies that it will be available as a Collection.
The View consists of a Form.

Displaying the Files

For displaying the records, an HTML Table is used. A FOR EACH loop will be executed over the Model which will generate the HTML Table rows with the tblFiles records.
 

Form for Downloading the File

The Form consists of an HTML HiddenField and a Hidden Submit Button.
When any Download Link inside the HTML Table (Grid) is clicked, then the DownloadFile JavaScript function is called, which sets the FileId into the HiddenField and calls the click event of the Submit button which submits the Form.
When the Form is submitted, the DownloadFile Action method is called, which performs the File download operation.
@model  IEnumerable<Download_CSV_Database_MVC.Models.FileModel>
 
@{
     Layout = null;
}
 
<!DOCTYPE html>
 
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    @using (Html.BeginForm("DownloadFile", "Home", FormMethod.Post))
    {
        <input type="hidden" id="hfFileId" name="FileId" />
        <input type="submit" id="btnDownload" value="Download" style="display:none" />
    }
    <hr />
    <table border="0" cellpadding="0" cellspacing="0">
        <tr>
            <th style="width:120px">File Name</th>
            <th style="width:80px"></th>
        </tr>
        @foreach (var file in Model)
        {
            <tr>
                <td>@file.Name</td>
                <td><a href="javascript:;" onclick="DownloadFile(@file.Id)">Download</a></td>
            </tr>
        }
    </table>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
    <script type="text/javascript">
        function DownloadFile(fileId) {
            $("#hfFileId").val(fileId);
            $("#btnDownload")[0].click();
        };
    </script>
</body>
</html>
 
 

Screenshot

Download CSV file from Database in ASP.Net MVC
 
 

Downloads

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