Question

我认为枚举可能是要走的路，取决于动作（创建，删除）它取代了角色？然后我必须存储变量“ - ”，“++”，“＆gt; =”和“＆gt;” hrrmm。任何简单的建议都会很棒，我可以将它作为未来参考，以便我如何处理这样的问题！

public void ArrangeCategoriesOrderOnCreate(Category category)
{
    var tx = _session.BeginTransaction();
    var categories = _session.QueryOver<Category>()
        .Where(c => c.Parent.Id == category.Parent.Id && c.OrderInList >= category.OrderInList) // the >= category.OrderInList here
        .List<Category>();

    foreach(var item in categories)
    {
        item.OrderInList++; // The ++ here.
        _session.SaveOrUpdate(item);
    }
    tx.Commit();
}

public void ArrangeCategoriesOrderOnDelete(Category category)
{
    var tx = _session.BeginTransaction();
    var categories = _session.QueryOver<Category>()
        .Where(c => c.Parent.Id == category.Parent.Id && c.OrderInList > category.OrderInList) // the > category.OrderInList here
        .List<Category>();

    foreach(var item in categories)
    {
        item.OrderInList--; // the -- here.
        _session.SaveOrUpdate(item);
    }
    tx.Commit();
}

修改1

无法从Invoke，Invoke（值（CumbriaMD.Infrastructure.DataServices.CategoryDataServices +＆lt;＆gt; c_ DisplayClass8）.orderComparer，c.OrderInList，value（CumbriaMD.Infrastructure.DataServices.CategoryDataServices +）中确定成员类型＆lt;＆gt; c _DisplayClass8）.category.OrderInList），System.Linq.Expressions.InvocationExpression

跟踪：

[例外：无法从Invoke，Invoke（值（CumbriaMD.Infrastructure.DataServices.CategoryDataServices +＆lt;＆gt; c_ DisplayClass8）确定成员类型.orderComparer，c.OrderInList，value（CumbriaMD.Infrastructure.DataServices） .CategoryDataServices +＆lt;＆gt; c _DisplayClass8）.category.OrderInList），System.Linq.Expressions.InvocationExpression] NHibernate.Impl.ExpressionProcessor.ProcessBooleanExpression（表达式表达式）+1113 NHibernate.Impl.ExpressionProcessor.ProcessExpression（表达式表达式）+114 NHibernate.Impl.ExpressionProcessor.ProcessAndExpression（BinaryExpression表达式）+85 NHibernate.Impl.ExpressionProcessor.ProcessBinaryExpression（BinaryExpression表达式）+124 NHibernate.Impl.ExpressionProcessor.ProcessExpression（表达式表达式）+95 NHibernate.Impl.ExpressionProcessor.ProcessLambdaExpression（LambdaExpression表达式）+52 NHibernate.Impl.ExpressionProcessor.ProcessExpression（Expression 1 expression) +39 NHibernate.Criterion.QueryOver 2.Add（Expression 1 expression) +107 NHibernate.Criterion.QueryOver 2.Where（Expression 1 expression) +42 NHibernate.Criterion.QueryOver 2.NHibernate.IQueryOver.Where（Expression`1 expression）+42 < / p>

Answer 1

一种简单的启动方式是使用Func来区分常见功能，并消除大部分重复。

public void ArrangeCategoriesOrderOnCreate(Category category)
{
    ArrangeCategoriesOrderOnAction(category, (a,b) => a>=b, x => x + 1);
}

public void ArrangeCategoriesOrderOnDelete(Category category)
{
    ArrangeCategoriesOrderOnAction(category, (a,b) => a>b, x => x - 1);
}

public void ArrangeCategoriesOrderOnAction(Category category, 
                               Expression<Func<int, int, bool>> orderComparer,
                               Func<int, int> orderUpdateCalculator)
{
    var tx = _session.BeginTransaction();
    var categories = _session.QueryOver<Category>()
        .Where(c => c.Parent.Id == category.Parent.Id 
               && orderComparer(c.OrderInList, category.OrderInList))
        .List<Category>();

    foreach (var item in categories)
    {
        item.OrderInList = orderUpdateCalculator(item.OrderInList);
        _session.SaveOrUpdate(item);
    }
    tx.Commit();
}

当方法之间只有三个字符不同时，我怎么能用查询重构这个“几乎”重复的代码？

1 个答案: