SqlDataSource cannot get value from DeleteParameters

[Vinci]

I have a SqlDataSource binding with a grid panel.

DeleteCommand as follow

 DeleteCommand = "DELETE FROM TMPTM101DT2 WHERE TMDUSRID = @TMDUSRID AND TMDCMPNO = @TMDCMPNO AND TMDLABEL = @TMDLABEL AND TMDDTETIM = @TMDDTETIM"

and UpdateCommand

UpdateCommand="UPDATE TMPTM101DT2 SET 
           TMDNOMINAT = @TMDNOMINAT, 
           TMDENDBUY = @TMDENDBUY, 
           TMDRMK = @TMDRMK, 
           TMDCRTUSR = @TMDCRTUSR, 
           TMDCRTDTE = @TMDCRTDTE, 
           TMDLUPUSR = @TMDLUPUSR, 
           TMDLUPDTE = @TMDLUPDTE 
           WHERE TMDUSRID = @TMDUSRID AND TMDCMPNO = @TMDCMPNO AND TMDLABEL = @TMDLABEL AND TMDDTETIM = @TMDDTETIM">

The DeleteParameters and UpdateParameters are declared in same way and DeleteParameters just contains the keys.

             <DeleteParameters>
                <asp:Parameter  Name="TMDUSRID" Type="String"/>
                <asp:Parameter  Name="TMDDTETIM" Type="DateTime"/>
                <asp:Parameter  Name="TMDCMPNO" Type="String"/>
                <asp:Parameter  Name="TMDLABEL" Type="String"/>
             </DeleteParameters>
           <UpdateParameters>
                <asp:Parameter  Name="TMDUSRID" Type="String"/>
                <asp:Parameter  Name="TMDDTETIM" Type="DateTime"/>
                <asp:Parameter  Name="TMDCMPNO" Type="String"/>
                <asp:Parameter  Name="TMDLABEL" Type="String"/>
                <asp:Parameter  Name="TMDNOMINAT" Type="Int16"/>
                <asp:Parameter  Name="TMDENDBUY" Type="String"/>
                <asp:Parameter  Name="TMDRMK" Type="String"/>
                <asp:Parameter  Name="TMDCRTUSR" Type="String"/>
                <asp:Parameter  Name="TMDCRTDTE" Type="DateTime"/>
                <asp:Parameter  Name="TMDLUPUSR" Type="String"/>
                <asp:Parameter  Name="TMDLUPDTE" Type="DateTime"/>
           </UpdateParameters>

In this case, the update is work fine. However deleting is not work. I insert a break point at the event of onDeleting.
What I find is the parameter is declared in the deleting
This code return true

e.Command.Parameters.Contains("@TMDUSRID")

but the value is null.
following return null

e.Command.Parameters["@TMDUSRID"].Value

the Store of the gridpanel is declared like this

                                        <Store>
                                            <ext:Store ID="stoLbl" runat="server" DataSourceID="sdsLbl" OnAfterRecordInserted="stoLbl_OnAfterRecordInserted" OnBeforeRecordInserted="stoLbl_OnBeforeRecordInserted">
                                                <Model>
                                                    <ext:Model ID="Model3" runat="server" Name="Label" >
                                                        <Fields>
                                                            <ext:ModelField Name="TMDUSRID" ServerMapping="TMDUSRID"/>
                                                            <ext:ModelField Name="TMDDTETIM" ServerMapping="TMDDTETIM"/>
                                                            <ext:ModelField Name="TMDCMPNO" ServerMapping="TMDCMPNO"/>
                                                            <ext:ModelField Name="TMDCRTUSR" ServerMapping="TMDCRTUSR"/>
                                                            <ext:ModelField Name="TMDCRTDTE" ServerMapping="TMDCRTDTE"/>
                                                            <ext:ModelField Name="TMDLUPUSR" ServerMapping="TMDLUPUSR"/>
                                                            <ext:ModelField Name="TMDLUPDTE" ServerMapping="TMDLUPDTE"/>
                                                            <ext:ModelField Name="TMDLABEL" ServerMapping="TMDLABEL"/>
                                                            <ext:ModelField Name="TMDNOMINAT" ServerMapping="TMDNOMINAT" Type="Boolean"/>
                                                            <ext:ModelField Name="TMDENDBUY" ServerMapping="TMDENDBUY"/>
                                                            <ext:ModelField Name="TMDRMK" ServerMapping="TMDRMK"/>
                                                        </Fields>
                                                    </ext:Model>
                                                </Model>

                                                <Listeners>
                                                    <Exception Handler="Ext.Msg.alert('Operation failed', operation.getError());" />                
                                                    <Write Handler="Ext.Msg.alert('Write', 'The data successfully saved');" />
                                                </Listeners>

                                            </ext:Store>
                                        </Store>

I do the same thing at the event of Updating, those parameters work fine and get value.

Is there any possible reason??