VS 2005 GridView 中如何自定義字符型列的列寬

表里如是文字的可在WIDTH中作定義。
但字符的不行。請問題如何
請賜教！  <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False"
        DataKeyNames="id" DataSourceID="ObjectDataSource1" EnableViewState="False" PageSize="20" Width="30px">
        <Columns>
            <asp:TemplateField>
               <ItemTemplate>
                   <input type="checkbox" name="id" value='<%# Eval("id") %>'>
               </ItemTemplate>
               <HeaderTemplate>
                   <input id="CheckAll" type="checkbox" onclick="selectAll(this);" />
               </HeaderTemplate>
               <FooterStyle HorizontalAlign="Center" />
               <ItemStyle Width="20px" />
            </asp:TemplateField>        
            <asp:TemplateField>
                <HeaderTemplate>
                    测试报告编号
                </HeaderTemplate>
                <ItemTemplate>
                    <div style="width:30px;">
                    <%# Eval("SGSReportNo")%>
                    </div>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <%# Eval("Manufactory")%>
                </ItemTemplate>
                <HeaderTemplate>
                    <div style="width: 35px; text-align: Center;">
                        厂商
                    </div>
                </HeaderTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <%# Eval("ModeName")%>
                </ItemTemplate>
                <HeaderTemplate>
                    <div style="width: 37px; text-align: Center;">
                        型号/材质
                    </div>
                </HeaderTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <%# DataBinder.Eval(Container.DataItem,"TestDate","{0:yyyy-MM-dd}") %>
                </ItemTemplate>
                <HeaderTemplate>
                    <div style="width: 70px; text-align: Center;">
                        测试日期
                    </div>
                </HeaderTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <%# DataBinder.Eval(Container.DataItem,"ExpireDate","{0:yyyy-MM-dd}") %>
                </ItemTemplate>
                <HeaderTemplate>
                    <div style="width: 70px; text-align: Center;">
                        过期日期
                    </div>
                </HeaderTemplate>
            </asp:TemplateField>
        </Columns>
        <EmptyDataTemplate>
            No Data
        </EmptyDataTemplate>
        <SelectedRowStyle Width="30px" Wrap="False" />
        <PagerStyle Wrap="True" />
        <HeaderStyle Width="30px" Wrap="False" />
    </asp:GridView>