how to use if statement in asp:repeater ItemTemplate

I know how to use if statement in ItemTemplate, such as <%#Eval("ID")==0?"aaa":"bbb"%>

but, in my code, I also have a question.

I binded the data to repeater,but in the row one, the column"tuijian" is DBNull.

<asp:Repeater ID="repALL" runat="server">
<ItemTemplate>
    <div class="table_style2">
        <%
            object objComID = ((System.Data.DataTable)repALL.DataSource).Rows[_nIndex]["ComID"];
            object objJoinID = ((System.Data.DataTable)repALL.DataSource).Rows[_nIndex]["JoinID"];
            _nIndex++;
            if (objComID != System.DBNull.Value)
            { %>
        <%# Convert.ToInt32(Eval("tuijian"))%>
        <%}
            else if (objJoinID != System.DBNull.Value)
            { %>

        <%#Convert.ToInt16(Eval("ID"))%>
        <%} %>
    </div>
</ItemTemplate>

so the code is error on <%# Convert.ToInt32(Eval("tuijian"))%>.

I rewrite the code like

<asp:Repeater ID="repALL" runat="server">
<ItemTemplate>
    <div class="table_style2">
        <%
            object objComID = ((System.Data.DataTable)repALL.DataSource).Rows[_nIndex]["ComID"];
            object objJoinID = ((System.Data.DataTable)repALL.DataSource).Rows[_nIndex]["JoinID"];
            _nIndex++;
            if (objComID != System.DBNull.Value)
            { %>                            
                    <%# Convert.ToInt32(Eval("ID"))%>                                    
        <%}
            else if (objJoinID != System.DBNull.Value)
            { %>

                    <%#Convert.ToInt16(Eval("ID"))%>
        <%} %>
    </div>
</ItemTemplate>

the results can be showed in the web.