Download Files from GridView based on CommandArgument using C# and VB.Net in ASP.Net

Hi subham,

Refer the below sample.

HTML

<asp:FileUpload ID="FileUpload1" runat="server" />
<br />
<asp:Button OnClick="Button1_Click" Text="Bind" runat="server" />
<br />
<asp:GridView ID="GridView1" runat="server" OnRowCommand="GridView1_RowCommand">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:LinkButton Text="Download" runat="server" CommandName="Download" CommandArgument='<%# Eval("File") %>'></asp:LinkButton>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Code

C#

protected void Button1_Click(object sender, EventArgs e)
{
    if (FileUpload1.HasFile)
    {
        FileUpload1.PostedFile.SaveAs(Server.MapPath("~/Data/") + FileUpload1.FileName);
    }

    DataTable dt = new DataTable();
    dt.Columns.Add("File", typeof(string));
    dt.Columns.Add("Size", typeof(string));
    dt.Columns.Add("Type", typeof(string));
    foreach (string str in System.IO.Directory.GetFiles(Server.MapPath("~/Data")))
    {
        System.IO.FileInfo fi = new System.IO.FileInfo(str);
        dt.Rows.Add(fi.Name, fi.Length, fi.Extension);
    }
    GridView1.DataSource = dt;
    GridView1.DataBind();
}

protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "Download")
    {
        Response.Clear();
        Response.ContentType = "application/octet-stream";
        Response.AppendHeader("content-disposition", "filename=" + e.CommandArgument);
        Response.TransmitFile(Server.MapPath("~/Data/") + e.CommandArgument);
        Response.End();

    }
}

VB.Net

Protected Sub Button1_Click(sender As Object, e As EventArgs)
	If FileUpload1.HasFile Then
		FileUpload1.PostedFile.SaveAs(Server.MapPath("~/Data/") + FileUpload1.FileName)
	End If

	Dim dt As New DataTable()
	dt.Columns.Add("File", GetType(String))
	dt.Columns.Add("Size", GetType(String))
	dt.Columns.Add("Type", GetType(String))
	For Each str As String In System.IO.Directory.GetFiles(Server.MapPath("~/Data"))
		Dim fi As New System.IO.FileInfo(str)
		dt.Rows.Add(fi.Name, fi.Length, fi.Extension)
	Next
	GridView1.DataSource = dt
	GridView1.DataBind()
End Sub

Protected Sub GridView1_RowCommand(sender As Object, e As GridViewCommandEventArgs)
	If e.CommandName = "Download" Then
		Response.Clear()
		Response.ContentType = "application/octet-stream"
		Response.AppendHeader("content-disposition", "filename=" + e.CommandArgument)
		Response.TransmitFile(Server.MapPath("~/Data/") + e.CommandArgument)

		Response.[End]()
	End If
End Sub

Screenshot