/// <summary>
/// 确定序列是否包含任何元素。
/// </summary>
/// <typeparam name="T">表实体类型</typeparam>
/// <param name="queryable">查询对象</param>
/// <param name="expression">表达式条件</param>
/// <returns>count>0返回true</returns>
public static bool Any <T>(this Queryable <T> queryable, Expression <Func <T, bool> > expression)
{
var type = queryable.Type;
queryable.WhereIndex = queryable.WhereIndex + 100;
ResolveExpress re = new ResolveExpress(queryable.WhereIndex);
re.ResolveExpression(re, expression, queryable.DB);
queryable.WhereValue.Add(re.SqlWhere);
queryable.Params.AddRange(re.Paras);
return(queryable.Count() > 0);
}
/// <summary>
/// 返回序列的唯一元素；如果该序列并非恰好包含一个元素，否则返回null。
/// </summary>
/// <typeparam name="T">表实体类型</typeparam>
/// <param name="queryable">查询对象</param>
/// <param name="expression">表达式条件</param>
/// <returns>T</returns>
public static T SingleOrDefault <T>(this Queryable <T> queryable, Expression <Func <T, bool> > expression)
{
var type = queryable.Type;
queryable.WhereIndex = queryable.WhereIndex + 100;
ResolveExpress re = new ResolveExpress(queryable.WhereIndex);
re.ResolveExpression(re, expression, queryable.DB);
queryable.WhereValue.Add(re.SqlWhere);
queryable.Params.AddRange(re.Paras);
return(queryable.ToList().SingleOrDefault());
}
/// <summary>
/// 条件筛选
/// </summary>
/// <typeparam name="T">表实体类型</typeparam>
/// <typeparam name="T2">表实体类型</typeparam>
/// <typeparam name="T3">表实体类型</typeparam>
/// <typeparam name="T4">表实体类型</typeparam>
/// <typeparam name="T5">表实体类型</typeparam>
/// <param name="queryable">查询对象</param>
/// <param name="expression">表达式条件</param>
/// <returns>Queryable</returns>
public static Queryable <T> Where <T, T2, T3, T4, T5>(this Queryable <T> queryable, Expression <Func <T, T2, T3, T4, T5, bool> > expression)
{
var type = queryable.Type;
queryable.WhereIndex = queryable.WhereIndex + 100;
ResolveExpress re = new ResolveExpress(queryable.WhereIndex);
re.Type = ResolveExpressType.nT;
re.ResolveExpression(re, expression, queryable.DB);
queryable.Params.AddRange(re.Paras);
queryable.WhereValue.Add(re.SqlWhere);
return(queryable);
}
/// <summary>
/// 联表查询
/// </summary>
/// <typeparam name="T">第一个表的对象</typeparam>
/// <typeparam name="T2">联接表的对象</typeparam>
/// <typeparam name="T3">联接表的对象</typeparam>
/// <param name="queryable">查询对象</param>
/// <param name="expression">条件表达式</param>
/// <param name="type">Join的类型</param>
/// <returns>Queryable</returns>
public static Queryable <T> JoinTable <T, T2, T3>(this Queryable <T> queryable, Expression <Func <T, T2, T3, object> > expression, JoinType type = JoinType.LEFT)
{
queryable.DB.InitAttributes <T3>();
ResolveExpress re = new ResolveExpress();
queryable.WhereIndex = queryable.WhereIndex + 100;
re.Type = ResolveExpressType.nT;
var exLeftStr = Regex.Match(expression.ToString(), @"\((.+?)\).+").Groups[1].Value;
var exLeftArray = exLeftStr.Split(',');
var shortName1 = exLeftArray[1];
var shortName2 = exLeftArray[2];
re.ResolveExpression(re, expression, queryable.DB);
string joinTypeName = type.ToString();
string joinTableName = null;
if (queryable.DB._mappingTableList.IsValuable())
{
//别名表
if (queryable.DB._mappingTableList.IsValuable())
{
string name = typeof(T3).Name;
if (queryable.DB._mappingTableList.Any(it => it.Key == name))
{
joinTableName = queryable.DB._mappingTableList.First(it => it.Key == name).Value;
}
}
}
if (joinTableName.IsNullOrEmpty())
{
joinTableName = typeof(T3).Name;
}
string joinStr = string.Format(" {0} JOIN {1} {2} ON {3} ",
/*0*/ queryable.JoinTableValue.Count == 0 ? (" " + shortName1 + " " + joinTypeName) : joinTypeName.ToString(),
/*1*/ joinTableName.GetTranslationSqlName(),
/*2*/ shortName2,
/*3*/ re.SqlWhere.Trim().TrimStart('A').TrimStart('N').TrimStart('D')
);
queryable.JoinTableValue.Add(joinStr);
queryable.Params.AddRange(re.Paras);
return(queryable);
}
