问题描述
我有一个通用的
List<MyClass>
其中 MyClass
有一个属性 InvoiceNumber
,其中包含以下值:
where MyClass
has a property InvoiceNumber
which contains values such as:
200906/1
200906/2
..
200906/10
200906/11
200906/12
200906/1
200906/2
..
200906/10
200906/11
200906/12
我的列表绑定到一个
BindingList<T>
支持使用 linq 排序:
which supports sorting with linq:
protected override void ApplySortCore(
PropertyDescriptor property, ListSortDirection direction)
{
_sortProperty = property;
_sortDirection = direction;
var items = this.Items;
switch (direction)
{
case ListSortDirection.Ascending:
items = items.OrderByDescending(x => property.GetValue(x)).ToList();
break;
case ListSortDirection.Descending:
items = items.OrderByDescending(x => property.GetValue(x)).ToList();
break;
}
this.Items = items;
}
但是默认的比较器排序(按预期)是这样的:
However the default comparer sorts (as supposed) like this:
200906/1
200906/10
200906/11
200906/12
200906/2
200906/1
200906/10
200906/11
200906/12
200906/2
在这种情况下很糟糕.
现在我想使用我自己的IComparer
.它看起来像这样:
Now I want to use my own IComparer<T>
with this. It looks like this:
public class MyComparer : IComparer<Object>
{
public int Compare(Object stringA, Object stringB)
{
String[] valueA = stringA.ToString().Split('/');
String[] valueB = stringB.ToString().Split('/');
if(valueA .Length != 2 || valueB .Length != 2)
return String.Compare(stringA.ToString(), stringB.ToString());
if (valueA[0] == valueB[0])
{
return String.Compare(valueA[1], valueB[1]);
}
else
{
return String.Compare(valueA[0], valueB[0]);
}
}
}
并更改了 ApplySortCore
代码以使用此 IComparer
:
and changed the ApplySortCore
code to use this IComparer
:
case ListSortDirection.Ascending:
MyComparer comparer = new MyComparer();
items = items.OrderByDescending(
x => property.GetValue(x), comparer).ToList();
break;
当我调试代码时,我看到 MyComparer.Compare(object, object)
被多次调用并为比较方法返回正确的值 (-1, 0, 1).
When I debug my code, I see that MyComparer.Compare(object, object)
is called multiple times and returns the right values (-1, 0, 1) for a compare method.
但我的列表仍然以错误"的方式排序.我错过了什么吗?我不知道.
But my list is still sorted the "wrong" way. Am I missing something? I have no clue.
推荐答案
我觉得你的比较器有问题.您仍然只是按照默认的文本顺序进行排序.您当然想解析这两个数字并基于此进行排序:
Your comparer looks wrong to me. You're still just sorting in the default text ordering. Surely you want to be parsing the two numbers and sorting based on that:
public int Compare(Object stringA, Object stringB)
{
string[] valueA = stringA.ToString().Split('/');
string[] valueB = stringB.ToString().Split('/');
if (valueA.Length != 2 || valueB.Length != 2)
{
stringA.ToString().CompareTo(stringB.ToString());
}
// Note: do error checking and consider i18n issues too :)
if (valueA[0] == valueB[0])
{
return int.Parse(valueA[1]).CompareTo(int.Parse(valueB[1]));
}
else
{
return int.Parse(valueA[0]).CompareTo(int.Parse(valueB[0]));
}
}
(请注意,这不符合您的问题,即您已经调试并验证了 Compare 返回了正确的值 - 但恐怕我怀疑在这方面存在人为错误.)
(Note that this doesn't sit well with your question stating that you've debugged through and verified that Compare is returning the right value - but I'm afraid I suspect human error on that front.)
此外,Sven 的权利 - 更改 items
的值根本不会更改您的绑定列表.您应该添加:
Additionally, Sven's right - changing the value of items
doesn't change your bound list at all. You should add:
this.Items = items;
在方法的底部.
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