/// <summary>集合相减</summary>
/// <param name="entities1">第一个实体集合</param>
/// <param name="entities2">第二个实体集合</param>
/// <returns></returns>
public static EntityList <T> operator -(EntityList <T> entities1, EntityList <T> entities2)
{
//if (entities1 == null || entities1.Count < 1) return null;
if (entities1 == null || entities1.Count < 1)
{
return(entities1);
}
EntityList <T> list = new EntityList <T>();
foreach (T item in entities1)
{
if (entities2 != null && !entities2.Contains(item))
{
list.Add(item);
}
}
//if (list == null || list.Count < 1) return null;
return(list);
}
/// <summary>根据指定项查找字符串。忽略大小写</summary>
/// <param name="name">属性名</param>
/// <param name="value">属性值</param>
/// <returns></returns>
public EntityList <T> FindAllIgnoreCase(String name, String value)
{
//if (Count < 1) return null;
if (Count < 1)
{
return(this);
}
EntityList <T> list = new EntityList <T>();
foreach (T item in this)
{
if (item == null)
{
continue;
}
if (String.Equals((String)item[name], value, StringComparison.OrdinalIgnoreCase))
{
list.Add(item);
}
}
//if (list == null || list.Count < 1) return null;
return(list);
}
/// <summary>检索与指定谓词定义的条件匹配的所有元素。</summary>
/// <param name="match">条件</param>
/// <returns></returns>
public new EntityList <T> FindAll(Predicate <T> match)
{
//if (Count < 1) return null;
if (Count < 1)
{
return(this);
}
EntityList <T> list = new EntityList <T>();
foreach (T item in this)
{
if (item == null)
{
continue;
}
if (match(item))
{
list.Add(item);
}
}
//if (list == null || list.Count < 1) return null;
return(list);
}
/// <summary>根据指定项查找。没有数据时返回空集合而不是null</summary>
/// <param name="names">属性名集合</param>
/// <param name="values">属性值集合</param>
/// <param name="ignoreCase">对于字符串字段是否忽略大小写</param>
/// <returns></returns>
public EntityList <T> FindAll(String[] names, Object[] values, Boolean ignoreCase = false)
{
if (Count < 1)
{
return(this);
}
FieldItem field = Factory.Table.FindByName(names[0]);
if (field != null && (field.IsIdentity || field.PrimaryKey))
{
// 唯一键为自增且参数小于等于0时，返回空
if (Helper.IsNullKey(values[0], field.Type))
{
return(new EntityList <T>());
}
}
// 特殊处理字符忽略大小写的情况
var ss = new Boolean[values.Length];
// 特殊处理整数类型，避免出现相同值不同整型而导致结果不同
var ts = new Boolean[values.Length];
var vs = new Int64[values.Length];
for (int i = 0; i < values.Length; i++)
{
field = Factory.Table.FindByName(names[i]);
if (field != null)
{
ss[i] = field.Type == typeof(String);
ts[i] = field.Type.IsIntType();
}
if (values[i] == null)
{
continue;
}
// 整型统一转为Int64后再比较，因为即使数值相等，类型不同的对象也是不等的
ts[i] |= values[i].GetType().IsIntType();
if (ts[i])
{
vs[i] = Convert.ToInt64(values[i]);
}
ss[i] |= values[i].GetType() == typeof(String);
}
var list = new EntityList <T>();
for (int k = 0; k < Count; k++)
{
var item = this[k];
if (item == null)
{
continue;
}
var b = true;
for (int i = 0; i < names.Length; i++)
{
var iv = item[names[i]];
if (!Object.Equals(iv, values[i]) &&
// 整数相等比较
!(ts[i] && Convert.ToInt64(iv) == vs[i]) &&
// 字符串不区分大小写比较，判定""和null为相等
!(ss[i] && ignoreCase && (iv + "").EqualIgnoreCase(values[i] + "")))
{
b = false;
break;
}
}
if (b)
{
list.Add(item);
}
}
return(list);
}
