How does FormView EditTemplate update values in ObjectDataSource UpdateParameters under the hood?

Question

I have a FormView bound to an ObjectDataSource.

* ObjectDataSource definition (omitted portion of it for simplicity)*

<asp:ObjectDataSource 
    ID="odsHousehold" 
    runat="server"
    TypeName="BLL.Households"
    ConflictDetection="OverwriteChanges"
    UpdateMethod="UpdateHousehold" 
    >
    <UpdateParameters>
        <asp:Parameter Name="sName" Type="String" Direction="Input" />
        <asp:Parameter Name="sAddress" Type="String" Direction="Input" DefaultValue="" />
        <asp:Parameter Name="sCity" Type="String" Direction="Input" DefaultValue="" />
        <asp:Parameter Name="sState" Type="String" Direction="Input" DefaultValue="" />
        <asp:Parameter Name="sZip" Type="String" Direction="Input" DefaultValue="" />
    </UpdateParameters>
</asp:ObjectDataSource>

* FormView definition (omitted portion of it for simplicity) *

   <asp:FormView 
    ID="fvHousehold"
    runat="server"
    DataKeyNames="HouseholdID"
    DataSourceID="odsHousehold"
    HorizontalAlign = "Left"
 >
<EditItemTemplate>
<asp:TextBox ID="txtHouseHoldName" runat="server" MaxLength="50" Width="100%" Text='<%# Bind("HouseholdName") %>'></asp:TextBox>
<asp:TextBox ID="txtAddress" runat="server" MaxLength="50" Width="100%" Text='<%# Bind("Address") %>'></asp:TextBox>
<asp:TextBox ID="txtCity" runat="server" MaxLength="50" Width="100%" Text='<%# Bind("City") %>'></asp:TextBox>
<asp:TextBox ID="txtState" runat="server" MaxLength="50" Width="100%" Text='<%# Bind("State") %>'></asp:TextBox>
<asp:TextBox ID="txtZip" runat="server" MaxLength="50" Width="100%" Text='<%# Bind("Zip") %>'></asp:TextBox>
 <asp:Button ID="btnUpdateHousehold" runat="server" Text="Update" CommandName="Update" />
</EditItemTemplate>
</asp:FormView>

I'd like to know: how does the FormView know which UpdateParameter to populate with which EditTemplate TextBox when the Update button is clicked?
For instance, I haven't instructed "txtAddress" in the FormView to populate the UpdateParameter "sAddress" but InputParameters["sAddress"] contains the Text value of txtAddress. How does it know to do that?

Could any guru enlighten me?

Thank you so much,

Cullen

Answer 1

"how does the FormView know which UpdateParameter to populate with which EditTemplate TextBox when the Update button is clicked?"

I believe the simple answer is: it knows because of the Bind statements you put in the TextBox controls. E.g. txtAddress has "Bind("Address")" so when the update is called, it has a connection between txtAddress and parameter "Address"