Ho provato, ma non funziona.



Ho aggiunto un sqldatasource e un gridview alla pag, poi ho inserito la tua parte di codice, ma purtroppo non funziona

codice:
<script runat="server">
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            DataRowView drv = (DataRowView)e.Row.DataItem;
            string sVal = drv.Row["link"].ToString();

            HyperLink HyperLink1 = (HyperLink)e.Row.FindControl("HyperLink1");
            HyperLink1.Text = "Metti qui il testo del link";
            HyperLink1.NavigateUrl = sVal;
            HyperLink1.Attributes.Add("onClick", "javascript:alert(...);");
        }
    }
</script>

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:con %>" SelectCommand="SELECT * FROM [tb_paging]"></asp:SqlDataSource>
        <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False" DataKeyNames="id" DataSourceID="SqlDataSource1" PageSize="5">
            <Columns>
                <asp:BoundField DataField="id" HeaderText="id" InsertVisible="False" ReadOnly="True"
                    SortExpression="id" />
                <asp:BoundField DataField="testo" HeaderText="testo" SortExpression="testo" />
                <asp:BoundField DataField="link" HeaderText="link" SortExpression="link" />

            </Columns>
        </asp:GridView>

Dove sbaglio?