Simple databinding to gridview columns

Question

I have a GridView that I use to show my users the result of a search. I want to allow them to choose which columns are shown on the GridView when performing their search. Simple enough, yes? I wanted to try doing this using just databinding, no events. Unfortunately, my code fails to update the GridView using checkboxes bound to the column's Visible property. The state of the chechboxes changes, but the Visible property of the columns does not.

Snippet of Search.aspx:

<myControl:FacultyGridView ID="FacultyGridView1" runat="server" />
    <asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
    <asp:CheckBox ID="CheckBox1" runat="server" Text='<%# Eval("HeaderText") %>' Checked='<%# Bind("Visible") %>' AutoPostBack=true/></ItemTemplate>
</asp:Repeater>

Code-behind snippet in Search.aspx.cs:

protected void Page_Load(object sender, EventArgs e)
{
     Repeater1.DataSource = FacultyGridView1.GridView.Columns;
     Repeater1.DataBind();
}

To be clear, the GridView is exposed as a public property of a user control named FacultyGridView. Relevant snippet of FacultyGridView.ascx:

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
    AllowPaging="True" AllowSorting="True" PageSize="25">
    <PagerSettings Mode="NumericFirstLast" Position="TopAndBottom" />
    <Columns>
        <asp:BoundField DataField="Name" HeaderText="Name" ReadOnly="True" SortExpression="Name" />
        <asp:TemplateField HeaderText="University" SortExpression="UniversityID">
            <ItemTemplate>
                <asp:Label ID="Label1" runat="server" Text='<%# Eval("University.Name") %>' />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Division">
            <ItemTemplate>
                <asp:Repeater ID="Repeater1" runat="server" DataSource='<%# Eval("DivisionMemberships") %>'>
                    <ItemTemplate>
                        <asp:Label ID="Label2" runat="server" Text='<%# Eval("Division.Name") %>'></asp:Label>
                    </ItemTemplate>
                </asp:Repeater>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Title" HeaderText="Title" ReadOnly="True" SortExpression="Title" />
        <asp:TemplateField HeaderText="Research Type">
            <ItemTemplate>
                <asp:Repeater ID="Repeater1" runat="server" DataSource='<%# Eval("ResearchTypeMappings") %>'>
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Eval("ResearchType.Name") %>'></asp:Label>
                    </ItemTemplate>
                </asp:Repeater>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Expertise" HeaderText="Expertise" ReadOnly="True" SortExpression="Expertise" />
        <asp:HyperLinkField DataNavigateUrlFields="Website" DataTextField="Website" HeaderText="Website"
            SortExpression="Website" />
        <asp:BoundField DataField="Phone" HeaderText="Phone" ReadOnly="True" SortExpression="Phone" />
        <asp:TemplateField HeaderText="Email Address" SortExpression="EmailAddress">
            <ItemTemplate>
                <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%# Eval("EmailAddress", "mailto:{0}") %>'
                    Text='<%# Eval("EmailAddress") %>'></asp:HyperLink>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Finally, I should mention that the GridView is bound by a Button on the page, but I am not getting updates to the Visible property whether I play with the checkboxes before or after databinding. Furthermore, I have not seen my desired behavior when binding the repeater only on the first Page_Load() using if(!IsPostBack), nor by not using Checkbox.AutoPostback true or false. Any clue as to what I'm doing wrong? I expect it to be something simple, but I'm a bit green here.

As a note: I know how to do this easily with events, but I want to do it with databinding as a learning exercise.

Answer 1

Probably because every time the grid is bound to the data, the column & settings are recreated (with-out your changes).