ObjectDataSource Selected Event Raised Twice . . . Why?

Question

User435566049 posted

I have a page that contains at least two ObjectDataSources, one that displays the details of a record (sourceRecord), and one that contains a list of categories (sourceCategories).  I have a FormView that uses sourceRecord as its data source.  Inside the FormView's EditItemTemplate, there is a DropDownList that uses sourceCategories as its datasource.

I use the Selected event for both of these ObjectDataSources in my code.  For reasons I cannot understand, the Selected event for sourceRecord is only raised once, but the Selected event for sourceCategories is raised twice.

Here is the code for the two ObjectDataSources:

<asp:ObjectDataSource ID="sourceRecord" runat="server" 
    SelectMethod="GetGraybookRecordByID" 
    TypeName="AFATempeDB.GraybookComponent.GraybookDB" 
    onselected="sourceGraybookDocument_Selected" 
    UpdateMethod="UpdateGraybookRecord" 
    OldValuesParameterFormatString="original_{0}">

    <UpdateParameters>
    ...               
    </UpdateParameters>

    <SelectParameters>
        <asp:QueryStringParameter DefaultValue="0" Name="record_id" 
            QueryStringField="DocID" Type="Int32" />
    </SelectParameters>
            
</asp:ObjectDataSource>
    
<asp:ObjectDataSource ID="sourceCategories" runat="server" 
    SelectMethod="GetAFSDocumentList" 
    TypeName="AFATempeDB.AFSDocumentsComponent.AFSDocumentsDB" 
    onselected="sourceAFSDocuments_Selected">
            
    <SelectParameters>
        <asp:ControlParameter ControlID="FormView1$chkWIUGRD_Fletcher" DefaultValue="false" 
            Name="wiugrd_fletcher" PropertyName="Checked" Type="Boolean" />
    </SelectParameters>
            
</asp:ObjectDataSource>

Can anyone explain why the Selected event is being raised twice and what I can do to fix it?