Question

这个LINQ：

public IEnumerable<InventoryItem> GetDepartmentRange(double deptBegin, double deptEnd)
{
    // Break the doubles into their component parts:
    int deptStartWhole = (int)Math.Truncate(deptBegin);
    int startFraction = (int)((deptBegin - deptStartWhole) * 100);
    int deptEndWhole = (int)Math.Truncate(deptEnd);
    int endFraction = (int)((deptBegin - deptEndWhole) * 100);

    return inventoryItems.Where(d => d.dept >= deptStartWhole).Where(e => e.subdept >= startFraction)
        .Where(f => f.dept <= deptEndWhole)
        .Where(g => g.subdept >= endFraction)
        .OrderBy(o => o.dept)
        .OrderBy(s => s.subdept);
}

...在我输入时返回预期的数据：

http://localhost:28642/api/inventoryitems/GetDeptRange/1.1/79.99/

...即（子集）：

<InventoryItem>
<Description>LID - Blank & Ten PLU</Description>
<ID>110</ID>
<OpenQty>0</OpenQty>
<UPC>110</UPC>
<UnitCost>4</UnitCost>
<UnitList>5</UnitList>
<crv_id>0</crv_id>
<dept>2</dept>
<pksize>1</pksize>
<subdept>10</subdept>
<upc_pack_size>1</upc_pack_size>
<vendor_id>LOCATIONID</vendor_id>
<vendor_item/>
</InventoryItem>

<InventoryItem>
<Description>BLT 6PK LNNR</Description>
<ID>01820000978</ID>
<OpenQty>0</OpenQty>
<UPC>01820000988</UPC>
<UnitCost>19.45</UnitCost>
<UnitList>11.99</UnitList>
<crv_id>0</crv_id>
<dept>10</dept>
<pksize>6</pksize>
<subdept>10</subdept>
<upc_pack_size>1</upc_pack_size>
<vendor_id>CLAREROSE</vendor_id>
<vendor_item/>
</InventoryItem>

<InventoryItem>
<Description>LID - Eleven & Eleven PLU</Description>
<ID>111</ID>
<OpenQty>0</OpenQty>
<UPC>111</UPC>
<UnitCost>4</UnitCost>
<UnitList>5</UnitList>
<crv_id>0</crv_id>
<dept>2</dept>
<pksize>1</pksize>
<subdept>11</subdept>
<upc_pack_size>1</upc_pack_size>
<vendor_id>LOCATIONID</vendor_id>
<vendor_item/>
</InventoryItem>

...但是数据不是由dept和subdept排序的（它从dept 2，subdept 10到dept 10，subdept 10，到dept 2，subdept 11.为什么不按LINQ orderbys排序？怎么能我按照dept和subdept订购了吗？

Answer 1

你的上一次OrderBy吹走了你的第一个。您按dept订购了列表，然后按subdept 重新排序结果。

您要在此处使用ThenBy来保留第一个排序。

您的代码如下所示：

return inventoryItems.Where(d => d.dept >= deptStartWhole).Where(e => e.subdept >= startFraction)
    .Where(f => f.dept <= deptEndWhole)
    .Where(g => g.subdept >= endFraction)
    .OrderBy(o => o.dept)
    .ThenBy(s => s.subdept);

Answer 2

您应该使用ThenBy：

.Orderby(o => o.debt).ThenBy(s => s.subdept)

Answer 3

他们背靠背执行。因此它首先按部门排序然后由子部门单独排序，因此列表仅由子部门排序。您想使用此帖子中显示的ThenBy...系列方法：

How to use orderby with 2 fields in linq?

为什么我的LINQ OrderBys不起作用？

3 个答案: