Nested GridViews

I have a nested GridView in my project. The top level grid will display a list of names and a link-button. On clicking the link-button, the detail (child) grid will be shown with a OK button. When the OK button is pressed, the child grid should disappear

I will use the Pubs database, Authors table. The top-level grid called AuthorGrid will display last-names. The child-grid will display first-name for the selected author

Below is the HTML markup:

<asp:GridView ID="AuthorGrid" runat="server" DataSourceID="AuthorSql" 
                AutoGenerateColumns="false" DataKeyNames="au_lname"
                 OnSelectedIndexChanged="AuthorGrid_SelectedIndexChanged">
    <Columns>
        <asp:BoundField HeaderText="Author" DataField="au_lname" />
        <asp:TemplateField>
            <ItemTemplate>
                <asp:GridView ID="DetailGrid" runat="server" 
                OnRowCommand="DetailGrid_OK" 
                AutoGenerateColumns="false">
                    <Columns>
                        <asp:BoundField HeaderText="First name" DataField="au_fname" />
                        <asp:ButtonField CommandName="OK" Text="OK" />
                    </Columns>
                </asp:GridView>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:CommandField ShowSelectButton="true" SelectText="Show" />
    </Columns>
</asp:GridView>
<asp:SqlDataSource ID="AuthorSql" runat="server"
                    ConnectionString = "<%$ ConnectionStrings:Pubs %>"
                   SelectCommand="SELECT au_lname FROM Authors"
></asp:SqlDataSource>
<asp:SqlDataSource ID="DetailSql" runat="server" DataSourceMode="DataSet"
                    ConnectionString = "<%$ ConnectionStrings:Pubs %>"
                   SelectCommand="SELECT au_fname FROM Authors
                         WHERE au_lname=@lname"
>
    <SelectParameters>
        <asp:Parameter Type="String" Name="lname" />
    </SelectParameters>
</asp:SqlDataSource>

Note that AuthorGrid is bound to AuthorSql and DetailGrid is not bound. DetailGrid will bind to DetailSql (SqlDataSource) when an author is selected in the AuthorGrid. The code for showing DetailGrid is found in the OnSelectedIndexChanged EventHandler of the AuthorGrid:

protected void AuthorGrid_SelectedIndexChanged(object sender, EventArgs e)
{
    string lname = (string)AuthorGrid.SelectedValue;
    DetailSql.SelectParameters["lname"].DefaultValue = lname;
    DataSourceSelectArguments dssa = new DataSourceSelectArguments();
    DataView ds = (DataView)DetailSql.Select(dssa);
    GridView DetailGrid = (GridView)AuthorGrid.SelectedRow
				.FindControl("DetailGrid");
    DetailGrid.DataSource = ds;
    DetailGrid.DataBind();
}

Finally, when the OK button of the DetailGrid is clicked, the DetailGrid should disappear. This can be done by binding the DetailGrid to an empty datasource as follows:

protected void DetailGrid_OK(object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "OK")
    {
        GridView DetailGrid = (GridView)e.CommandSource;
        DetailGrid.DataBind();
    }
}