为什么我的LINQ OrderBys不起作用？

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);
}

...当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？我怎么能这样做由dept和subdept订购？

Answer 1

你的最后一次OrderBy打击你的第一次.您按顺序排列列表dept,然后重新排序结果subdept.

你想在这里使用的是ThenBy保留第一个订单.

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);