I need someone to show me the proper way to page in c# and asp.net

I need someone to show me the proper way to page in c# and asp.net

I have the code here. It does its job of parsing and uploading the csv
file into the datagrid but some have more then 300 lines and I need to
paginate them.
protected void CsvGridView_PageIndexChanging(object sender,
GridViewPageEventArgs e)
{
if (IsPostBack)
{
CsvGridView.Visible = true;
CsvGridView.PageIndex = e.NewPageIndex;
CsvGridView.DataBind();
}
}
I really need the help, I will try to help with your question as much as I
can. I have used this, but my gridview keeps disappearing and I have to
upload it again, when I upload it, it shows the page I just selected.