Exporting data fromn Gridview to CSV format

protected void btnExportCSV_Click(object sender, EventArgs e)

{

    Response.Clear();

    Response.Buffer = true;

    Response.AddHeader("content-disposition",

     "attachment;filename=SearchInfo.csv");

    Response.Charset = "";

    Response.ContentType = "application/text";

    dgSearchView.AllowPaging = false;

    dgSearchView.DataBind();

    StringBuilder sb = new StringBuilder();

    for (int k = 0; k < GridView1.Columns.Count; k++)

    {

        //add separator

        sb.Append(GridView1.Columns[k].HeaderText + ',');

    }

    //append new line

    sb.Append("\r\n");

    for (int i = 0; i < GridView1.Rows.Count; i++)

    {

        for (int k = 0; k < GridView1.Columns.Count; k++)

        {

            //add separator

            sb.Append(GridView1.Rows[i].Cells[k].Text + ',');

        }

        //append new line

        sb.Append("\r\n");

    }

    Response.Output.Write(sb.ToString());

    Response.Flush();

    Response.End();

}