How to Bind complex data to control in ListView (class User contain instance of class UserType) - asp.net

Question

I have 2 value class
public class UserType
{
public int ID;
public string TypeName;
}
public class User
{
public int ID;
public string UserName;
public UserType Type;
}
1 proccessing class
public class Users
{
public User[] GetUsers()
{
//Retrive and re turn User array
}
public int Update(User user, User old_user)
{
//Update user
}
}
1 ListView and 1 ObjectDataSource
<asp:ListView ID="lsvUser" runat="server" DataKeyNames="ID" DataSourceID="odsUser"
ItemPlaceholderID="plhItem" onitemupdating="lsvUser_ItemUpdating">
<LayoutTemplate>
<ul><asp:PlaceHolder ID="plhItem" runat="server"></asp:PlaceHolder></ul>
</LayoutTemplate>
<ItemTemplate>
<li>
<asp:Label ID="lblID" runat="server" Text='<%# Eval("ID") %>'></asp:Label>
<asp:Label ID="lblUserName" runat="server" Text='<%# Eval("UserName") %>'></asp:Label>
<asp:Label ID="lblTypeName" runat="server" Text='<%# Eval("Type.TypeName") %>'></asp:Label>
<asp:LinkButton ID="btEdit" runat="server" CssClass="button" CommandName="Edit" Text="Edit"></asp:LinkButton>
</li>
</ItemTemplate>
<EditItemTemplate>
<li class="editRow">
<asp:Textbox ID="txbUserName" runat="server" Text='<%# Bind("UserName") %>'></asp:Textbox >
<asp:Textbox ID="txbTypeName" runat="server" Text='<%# Bind("Type.TypeName") %>'></asp:Textbox >
</li>
</EditItemTemplate>
</asp:ListView>
<asp:ObjectDataSource ID="odsUser" runat="server" TypeName="BLL.Users" DataObjectTypeName="BLL.User" SelectMethod="GetUsers" UpdateMethod="Update" ConflictDetection="CompareAllValues" OldValuesParameterFormatString="old_{0}"></asp:ObjectDataSource>
When data is loaded into the ItemTemplate, the ListView interprets Type.TypeName and binds correctly,
but when updating the record, I cannot retrieve the old_user.Type from the old values. So old_user.Name and old_user.ID have values but old_user.Type is null.
Help me. I have been searching for about 2 days and cannot find a solution. I can bind data for a new user like this:
protected void lsvUser_ItemUpdating(object sender, ListViewUpdateEventArgs e)
{
e.NewValues.Add("Type", new BLL.UserType() { TypeName = Convert.ToString(((TextBox)lsvUser.EditItem.FindControl("txbTypeName")).Text) });
}
But I don't know how to retrieve the old values (how to retrive value of lblTypeName).
Help me. If there is a solution that doesn't require additional code in the ItemUpdating event, please teach me.
Thank you.

Answer 1

Add Type.TypeName as a DataKey, like this:
<asp:ListView ID="ListView1" runat="server" DataKeyNames="Type.TypeName">
And in your ItemUpdating event handler, retrieve the key value like this:
string typeName = (string)e.Keys["Type.TypeName"];
I'm not positive that "Type.TypeName will work, but some variation of that should work, whether it's Type.TypeName or just TypeName.