记录CAML的使用.

<Where>
    <And>
        <And>
            <Leq>
                <FieldRef Name="_x8d77__x59cb__x65e5__x671f_" />
                <Value Type="DateTime">{0}</Value>
            </Leq>
            <Eq>
                <FieldRef Name="_x5b8c__x6210__x6807__x5fd7_" />
                <Value Type="Choice">未完成</Value>
            </Eq>
        </And>
        <Eq>
            <FieldRef Name="_x4efb__x52a1__x540d__x79f0_" LookupId="TRUE"/>
            <Value Type="Lookup">{1}</Value>
        </Eq>
    </And>
</Where>

<!-- 当前登录用户  -->
<Eq>
    <FieldRef Name="_x4efb__x52a1__x6267__x884c__x4e" />
    <Value Type="Integer">
        <UserID Type="Integer" />
    </Value>
</Eq>

<!-- 当天  -->
<Eq>
    <FieldRef Name="Created" />
    <Value Type="DateTime">
        <Today />
    </Value>
</Eq>

<!-- ==null  -->
<IsNull>
 <FieldRef Name="_x53d1__x8d77__x90e8__x95e8_" />
</IsNull>