Download Files From GridView Link Button In Asp.Net C# VB.NET

This Example explains how to Download Files From GridView Link Button In Asp.Net Using C# VB.NET when files are saved or stored on server and their path or file name is saved in sql server database.

I have placed one FileUpload control on the page to upload files on the server, and saving id and file name in database. 

GridView on the page is used to display uploaded file and provide download link.

Create one table in sql database and add two columns ID (int identity) andFileName(Varchar).


HTML SOURCE OF PAGE

---

   1:  <asp:FileUpload ID="FileUpload1" runat="server"/>

   2:  <asp:Button ID="btnUpload" runat="server" 

   3:              onclick="btnUpload_Click" 

   4:              Text="Upload" />

   5:  <asp:Label ID="lblMessage" runat="server"></asp:Label>

   6:   

   7:  <asp:GridView ID="GridView1" runat="server" 

   8:                AutoGenerateColumns="False" 

   9:                DataSourceID="SqlDataSource1" 

  10:                onrowcommand="GridView1_RowCommand">

  11:  <Columns>

  12:  <asp:BoundField DataField="ID" HeaderText="ID" 

  13:                  SortExpression="ID" />

  14:  <asp:BoundField DataField="FileName" 

  15:                  HeaderText="FileName" 

  16:                  SortExpression="FileName" />

  17:   

  18:  <asp:ButtonField ButtonType="Link" Text="Download" 

  19:                   CommandName="Dwn" 

  20:                   HeaderText="Files" />

  21:  </Columns>

  22:  </asp:GridView>

  23:  <asp:SqlDataSource ID="SqlDataSource1" runat="server" 

  24:  ConnectionString=

  25:  "<%$ ConnectionStrings:ConnectionString %>" 

  26:  SelectCommand="SELECT [ID], [FileName] 

  27:                 FROM [Files]">

  28:  </asp:SqlDataSource>

Write below mentioned code in Click Event of upload button

C#

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01protected void btnUpload_Click(object sender, EventArgs e)

02    {

03        if (FileUpload1.HasFile)

04        {

05            string name = Path.GetFileName(FileUpload1.PostedFile.FileName);

06            string location = Server.MapPath("~/Docs/" + name);

07            FileUpload1.SaveAs(location);

08 

09            //Create SQL Connection and Command to Save File name in DataBase

10 

11            string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

12            SqlConnection sqlCon = new SqlConnection(connectionString);

13            string strInsert = "INSERT INTO Files(FileName) VALUES(@FileName)";

14            SqlCommand command = new SqlCommand(strInsert, sqlCon);

15            command.Parameters.AddWithValue("@FileName", name);

16            sqlCon.Open();

17            int result = command.ExecuteNonQuery();

18            sqlCon.Close();

19 

20            if (result > 0)

21                lblMessage.Text = "Upload Successful";

22        }

23        GridView1.DataBind();

24    }

VB.NET

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01Protected Sub btnUpload_Click(sender As Object, e As EventArgs)

02 If FileUpload1.HasFile Then

03  Dim name As String = Path.GetFileName(FileUpload1.PostedFile.FileName)

04  Dim location As String = Server.MapPath("~/Docs/" & name)

05  FileUpload1.SaveAs(location)

06 

07  'Create SQL Connection and Command to Save File name in DataBase

08 

09  Dim connectionString As String = ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString

10  Dim sqlCon As New SqlConnection(connectionString)

11  Dim strInsert As String = "INSERT INTO Files(FileName) VALUES(@FileName)"

12  Dim command As New SqlCommand(strInsert, sqlCon)

13  command.Parameters.AddWithValue("@FileName", name)

14  sqlCon.Open()

15  Dim result As Integer = command.ExecuteNonQuery()

16  sqlCon.Close()

17 

18  If result > 0 Then

19   lblMessage.Text = "Upload Successful"

20  End If

21 End If

22 GridView1.DataBind()

23End Sub

Write this code in RowCommand Event of GridView

C#

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01protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)

02    {

03        if (e.CommandName == "Dwn")

04        {

05            int index = Convert.ToInt32(e.CommandArgument);

06            GridViewRow row = GridView1.Rows[index];

07            string fName = row.Cells[1].Text;

08            Response.ContentType = "application/octet-stream";

09            Response.AddHeader("Content-Disposition", "attachment;filename=" + fName);

10            Response.TransmitFile(Server.MapPath("~/Docs/" + fName));

11            Response.End();

12        }

13    }

VB.NET

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01Protected Sub GridView1_RowCommand(sender As Object, e As GridViewCommandEventArgs)

02 If e.CommandName = "Dwn" Then

03  Dim index As Integer = Convert.ToInt32(e.CommandArgument)

04  Dim row As GridViewRow = GridView1.Rows(index)

05  Dim fName As String = row.Cells(1).Text

06  Response.ContentType = "application/octet-stream"

07  Response.AddHeader("Content-Disposition", "attachment;filename=" & fName)

08  Response.TransmitFile(Server.MapPath("~/Docs/" & fName))

09  Response.[End]()

10 End If

11End Sub