Is it possible to fill a detailsview with a datatable and still use templated fields without showing both sets of data?

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C#

ASP.NET

I have a detailsview that I am populating with a datatable. I also have templated fields for custom code. The detailsview shows both sets of data which are duplicates, one set from the datatable and the other set from the templated fields. I only want to display one set of the data, that being the templated fields. Can someone explain to me my falacies and suggest a better way to handle this please?

Also, I cannot use SqlDataSources due to the way this program was originally designed. The code I have is below and shortened in the detailsview to make it easier to read.

<asp:DetailsView ID="DetailsView1" runat="server" onmodechanging="DetailsView1_ModeChanging" OnItemUpdating="DetailsView1_ItemUpdating"
          DefaultMode="Edit" CssClass="panelStyle" OnDataBound="DetailsView1_DataBound" CausesValidation="false" GridLines="None"><%----%>
        <Fields>
            <asp:TemplateField HeaderText="Function Name">
                <EditItemTemplate>
                    <asp:DropDownList ID="ddlfunctions" runat="server"
                        DataSource='<%# _functionCollection %>' DataTextField="Display" DataValueField="Name">
                    </asp:DropDownList>
                    <br />
                </EditItemTemplate>
                <InsertItemTemplate>
                    <asp:TextBox ID="TextBox1" runat="server"
                        Text='<%# Bind("entryFunctionName") %>'></asp:TextBox>
                </InsertItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label1" runat="server" Text='<%# Bind("entryFunctionName") %>'></asp:Label>
                </ItemTemplate>
</Fields>
</asp:DetailsView>

string entryID;
        DataTable dtEdit = new DataTable();

        protected void gvEntries_SelectedIndexChanged(object sender, EventArgs e)
        {
            // Determine the index of the selected row.
            int index = gvEntries.SelectedIndex;
            entryID = gvEntries.DataKeys[index].Value.ToString();

            string queryString = ("Select [entryFunctionName], [entrySegment], [entryLOB]," +
            "[entryTime], [entryAccountNumber], [entryProgramRevOrg], [entryQuantity], " +
            "[entryNotes] From tblEntries Where entryEntryID = " + entryID);
            dtEdit = DDLGetData(queryString);

            DetailsView1.ChangeMode(DetailsViewMode.Edit);
            DetailsView1.DataSource = dtEdit;
            DetailsView1.DataBind();

            ModalPopupExtender1.Controls.Add(editPanel);
            ModalPopupExtender1.Show();
        }