In .aspx page :
——————
– Inside <asp:GridView -> columns tag add one template field like below :-

<asp:TemplateField HeaderText="Screen Shot">    <ItemTemplate>    <asp:Image ID="screenShot" runat="server" ImageUrl='<%# Eval("screenshot") %>' CssClass="image" AlternateText="No Screenshots available"/>    <asp:LinkButton ID="lnkDownload" runat="server" CommandArgument='<%# Eval("screenshot") %>' CommandName="cmd">Download</asp:LinkButton>   </ItemTemplate> </asp:TemplateField>

– Add one OnRowCommand=”GridView1_RowCommand” event inside <asp:GridView tag.
In .cs page :
——————

-Define the event "GridView1_RowCommand" as follows :-
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e){   if (e.CommandName == "cmd")   {      string filename = e.CommandArgument.ToString();      if (filename != "")      {         string path = MapPath(filename);         byte[] bts = System.IO.File.ReadAllBytes(path);          Response.Clear();         Response.ClearHeaders();          Response.AddHeader("Content-Type", "Application/octet-stream");         Response.AddHeader("Content-Length", bts.Length.ToString());         Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);         Response.BinaryWrite(bts);         Response.Flush();         Response.End();      }
}}

Important Points–
– Example is given for Image download, but You can download files of any type by just giving the path in “CommandArgument” attribute. – Q: What is ImageUrl='<%# Eval(“screenshot”) %>’ ??? – A: It is written to specify/evaluate the path of image that we got from dataset(column name in dataset is “screenshot”). –

Q: What is CommandArgument='<%# Eval(“screenshot”) %>’ ?

A: Again CommandArgument takes the ImageUrl which is obtained from the dataset.