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public static class PredicateExtensions
{
/// <summary>
/// 机关函数应用True时：单个AND有效，多个AND有效；单个OR无效，多个OR无效；混应时写在AND后的OR有效。即，设置为True时所有or语句应该放在and语句之后，否则无效
/// </summary>
public static Expression<Func<T, bool>> True<T>() { return f => true; }
/// <summary>
/// 机关函数应用False时：单个AND无效，多个AND无效；单个OR有效，多个OR有效；混应时写在OR后面的AND有效。 即，设置为False时所有or语句应该放在and语句之前，否则无效
/// </summary>
public static Expression<Func<T, bool>> False<T>() { return f => false; }
public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expression1,
Expression<Func<T, bool>> expression2)
{
var invokedExpression = Expression.Invoke(expression2, expression1.Parameters
.Cast<Expression>());
return Expression.Lambda<Func<T, bool>>(Expression.Or(expression1.Body, invokedExpression),
expression1.Parameters);
}
public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> expression1,
Expression<Func<T, bool>> expression2)
{
var invokedExpression = Expression.Invoke(expression2, expression1.Parameters
.Cast<Expression>());
return Expression.Lambda<Func<T, bool>>(Expression.And(expression1.Body,
invokedExpression), expression1.Parameters);
}
} -
/// <summary>
/// 获取指定type异常预警
/// </summary>
/// <param name="typeArray">整数数组</param>
/// <returns></returns>
public List<p2p_log_error> GetNewError(int[] typeArray)
{
var predicate = PredicateExtensions.False<p2p_log_error>();//设置为False，所有and条件都应该放在or之后，如where (type=1 or type=14) and status==0
foreach (var t in typeArray)
{
int type_temp= t;
predicate = predicate.Or(p => p.type == type_temp);
}
var result = entities.p2p_log_error.Where(predicate.Compile());
return result.Where(p => p.status == 0).OrderByDescending(i => i.id).ToList();
}