指数超出范围。必须是非负数且小于集合的大小。参数名称：index

Question

protected void Download_Click(object sender, EventArgs e)
{
    LinkButton link = sender as LinkButton;
    GridViewRow gvrow = link.NamingContainer as GridViewRow;
    string upload = GridView1.DataKeys[gvrow.RowIndex].Values.ToString();
    Response.ContentType = "files/apk";
    Response.AddHeader("Content-dispotision", "attachment;filepath1=\"" + upload + "\"");
    Response.TransmitFile(Server.MapPath(upload));
    Response.End();
}