asp:RadioButton chenked

<asp:RadioButton ID="rdoSmalImage" Text="小图上传" runat="server" Checked="True"  GroupName="types" AutoPostBack="True" />
<asp:RadioButton ID="rdoBigImage" runat="server" Text="原图上传" GroupName="types"   AutoPostBack="True"  />

asp页面中有两个单选按钮,

后台

if (rdoSmalImage.Checked)
                        type = 0;
                    else
                        type = 1;

我选中哪个if里面都是true 为什么.???

虽然值都是“true”但是提交的变量不一样啊~

ID="rdoSmalImage"

ID="rdoBigImage"