Se você conhece o índice das colunas que deseja exportar, como o seguinte:
Storeid | Encontro | Empid | Employeename | StartTime | EndTime | StartTime | Fim do tempo
Você precisa obter valores de colunas no índice = 0, 1, 2, 4, 7
Então seu código pode ser mais simples assim
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnExportCSV_Click(object sender, EventArgs e)
{
Response.Clear();
Response.Buffer = true;
Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.csv");
Response.Charset = "";
Response.ContentType = "application/text";
GridView1.AllowPaging = false;
GridView1.DataBind();
StringBuilder sb = new StringBuilder();
//add separator for header
sb.Append(GridView1.Columns[0].HeaderText).Append(",")
.Append(GridView1.Columns[1].HeaderText).Append(",")
.Append(GridView1.Columns[2].HeaderText).Append(",")
.Append(GridView1.Columns[4].HeaderText).Append(",")
.Append(GridView1.Columns[7].HeaderText).Append("\r\n");
for (int i = 0; i < GridView1.Rows.Count; i++)
{
DateTime date = DateTime.Parse(GridView1.Rows[i].Cells[1].Text);
if (date.DayOfWeek != DayOfWeek.Saturday
&& date.DayOfWeek != DayOfWeek.Sunday)
{
//add separator for each row
sb.Append(GridView1.Rows[i].Cells[0].Text).Append(",")
.Append(GridView1.Rows[i].Cells[1].Text).Append(",")
.Append(GridView1.Rows[i].Cells[2].Text).Append(",")
.Append(GridView1.Rows[i].Cells[4].Text).Append(",")
.Append(GridView1.Rows[i].Cells[7].Text).Append("\r\n");
}
}
Response.Output.Write(sb.ToString());
Response.Flush();
Response.End();
}
}