Error with the command

Change the PropertyName for the desc ControlParameter to SelectedValue :

  <asp:ControlParameter ControlID="int_list" Name="desc" PropertyName="SelectedValue" />

Sorry I still get this
Could not find control 'int_list' in ControlParameter 'desc'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Could not find control 'int_list' in ControlParameter 'desc'.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  

Stack Trace:


[InvalidOperationException: Could not find control 'int_list' in ControlParameter 'desc'.]
   System.Web.UI.WebControls.ControlParameter.Evaluate(HttpContext context, Control control) +3226150
   System.Web.UI.WebControls.Parameter.UpdateValue(HttpContext context, Control control) +152
   System.Web.UI.WebControls.ParameterCollection.UpdateValues(HttpContext context, Control control) +113
   System.Web.UI.WebControls.ParameterCollection.GetValues(HttpContext context, Control control) +47
   System.Web.UI.WebControls.SqlDataSourceView.InitializeParameters(DbCommand command, ParameterCollection parameters, IDictionary exclusionList) +444
   System.Web.UI.WebControls.SqlDataSourceView.ExecuteInsert(IDictionary values) +214
   System.Web.UI.DataSourceView.Insert(IDictionary values, DataSourceViewOperationCallback callback) +3696829
   System.Web.UI.WebControls.FormView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +678
   System.Web.UI.WebControls.FormViewRow.OnBubbleEvent(Object source, EventArgs e) +148
   System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +84
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3804
 


--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929

after I've changed it to be
    <asp:DropDownList ID="int_list"
        width="330px"
        DataSourceID="ds_int"
        runat="server"
        name="desc"
        DataTextField="int_desc"
        DataValueField="int_desc"
        PropertyName="SelectedValue" >
    </asp:DropDownList>

Is the int_list control contained within another control ?
Can you comment out the controlparameter and then view the source of the page and see what id the dropdownlist control has been given it may be something like :

myContainingControl$int_list

Just read your previous post again, the propertyname attribute should be on the controlparameter control not the dropdownlist control, I would also remove name=desc from the dropdownlist control as it might be confusing the compiler :

  <asp:ControlParameter ControlID="int_list" Name="desc" PropertyName="Text" />

    <asp:DropDownList ID="int_list"
        width="330px"
        DataSourceID="ds_int"
        runat="server"
        DataTextField="int_desc"
        DataValueField="int_desc"
    </asp:DropDownList

Many thanks. I am getting the same problem with these full codes of the relevant part. Please advise.
    <asp:FormView ID="int_fv" runat="server"
    DefaultMode="Insert"
    AutoGenerateColumns="false"
    BackColor="gray"
    AllowSorting="True"
    Title="Test"
    datasourceid="ds_user_int" >
    <InsertItemTemplate>
    <asp:DropDownList ID="int_list"
        width="330px"
        DataSourceID="ds_int"
        runat="server"
        BackColor="gray"
        DataTextField="int_desc"
        DataValueField="int_desc" >
    </asp:DropDownList>
    <asp:Textbox id="change_date" Text='<%# Bind("change_date") %>' runat="server" />
    <br />
    <asp:LinkButton ID="LinkButton6" runat="server" CommandName="insert">Insert</asp:LinkButton>
    &nbsp;<asp:LinkButton ID="LinkButton7" runat="server" CommandName="cancel">Cancel</asp:LinkButton>
    </InsertItemTemplate>
    <ItemTemplate>
        <asp:LinkButton ID="LinkButton1" runat="server" CommandName="new">New</asp:LinkButton>
        &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CommandName="delete">Delete</asp:LinkButton>
        &nbsp;<asp:LinkButton ID="LinkButton3" runat="server" CommandName="edit">Edit</asp:LinkButton>
    </ItemTemplate>
    <EmptyDataTemplate>
    <asp:Image ID="im1" AlternateText="No Data" runat="server" />
        <br />
        <asp:LinkButton ID="LinkButton1" runat="server" CommandName="new">New</asp:LinkButton>
    </EmptyDataTemplate>
    <HeaderStyle BackColor="gray">
    </HeaderStyle>
    <HeaderTemplate>
      <asp:Label runat="server" id="hdr1" width="330px" Text="Test" />
      <asp:Label runat="server" id="hdr2" Text="Update At" />
    </HeaderTemplate>
    <EditItemTemplate>
    <asp:DropDownList ID="int_list"
        width="330px"
        DataSourceID="ds_int"
        runat="server"
        name="desc"
        BackColor="gray"
        DataTextField="int_desc"
        DataValueField="int_desc"
        PropertyName="SelectedValue" >
    </asp:DropDownList>
    <asp:Textbox id="change_date" Text='<%# Bind("change_date") %>' runat="server" />
    <br />
    <asp:LinkButton ID="LinkButton4" runat="server" CommandName="update">Update</asp:LinkButton>
    &nbsp;<asp:LinkButton ID="LinkButton5" runat="server" CommandName="cancel">Cancel</asp:LinkButton>
    </EditItemTemplate>
    </asp:FormView>
    <asp:SqlDataSource
    ID="ds_user_int" Runat="server"
    ConnectionString="<%$ ConnectionStrings:Mssqlconn2 %>"
    ProviderName="System.Data.SqlClient"
    SelectCommand="select int_desc,change_date from tab2 order by 1"
    Insertcommand="insert into tab2 (user_id,int_desc,change_date) values (cast(@userid as decimal(10,0)),@desc,@dt)" >
          <insertparameters>
              <asp:ControlParameter ControlID="lb_userid" Name="userid" PropertyName="Text" />
              <asp:ControlParameter ControlID="int_list" Name="desc" PropertyName="Text" />
              <asp:ControlParameter ControlID="change_date" Name="dt" PropertyName="Text" />
          </insertparameters>
    </asp:SqlDataSource>
    <asp:SqlDataSource
    ID="ds_int" Runat="server"
    SelectCommand="select int_desc from tab3 where @age>20 and @sex='Male' order by 1"
    ConnectionString="<%$ ConnectionStrings:Mssqlconn2 %>"
    ProviderName="System.Data.SqlClient" >
        <SelectParameters>
            <asp:ControlParameter ControlID="lb_age" DefaultValue="0" Name="age"
                PropertyName="Text" />
            <asp:ControlParameter ControlID="rbl_sex" DefaultValue="M" Name="sex"
                PropertyName="SelectedValue" />
        </SelectParameters>
    </asp:SqlDataSource>
    <br /><br />
    ...