Selecionar linha gridView

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write(GridView1.SelectedRow.Cells[0].Text);
}
protected override void Render(HtmlTextWriter writer)
{
foreach (GridViewRow r in GridView1.Rows)
{
if (r.RowType == DataControlRowType.DataRow)
{
r.Attributes["onmouseover"] = "this.style.cursor='pointer';";
r.Attributes["onmouseout"] = "this.style.textDecoration='none';";
r.ToolTip = "Clique para selecionar";
r.Attributes["onclick"] = this.Page.ClientScript.GetPostBackClientHyperlink(this.GridView1, "Select$" + r.RowIndex, true);
}
}
base.Render(writer);
}
Então fazer (usando datakeys)
protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write(GridView1.DataKeys[GridView1.SelectedIndex]["id"].ToString());
}
ou então
GridView2.DataKeys[GridView2.SelectedIndex].Values[2]