public Queryable <T> Where(Expression <Func <T, object> > field, Operator op, object value)
{
LogicalBinaryExpression logical;
switch (op)
{
case Operator.Equal:
logical = SqlExpression.Equal(field, value);
break;
case Operator.LessThan:
logical = SqlExpression.LessThan(field, value);
break;
case Operator.LessThanOrEqual:
logical = SqlExpression.LessThanOrEqual(field, value);
break;
case Operator.GreaterThan:
logical = SqlExpression.GreaterThan(field, value);
break;
case Operator.GreaterThanOrEqual:
logical = SqlExpression.GreaterThanOrEqual(field, value);
break;
case Operator.In:
logical = SqlExpression.In(field, value);
break;
case Operator.StartWith:
logical = SqlExpression.Like(field, value, true, false);
break;
case Operator.EndWith:
logical = SqlExpression.Like(field, value, false, true);
break;
case Operator.Like:
logical = SqlExpression.Like(field, value, true, true);
break;
case Operator.NotEqual:
logical = SqlExpression.NotEqual(field, value);
break;
case Operator.Between:
var values = ((ICollection)value).Cast <object>();
if (values.Count() < 2)
{
throw new ArgumentException("value集合未包含两个元素。");
}
logical = SqlExpression.Between(field, values.First(), values.Skip(1).First());
break;
case Operator.NotIn:
logical = SqlExpression.NotIn(field, value);
break;
default:
throw new NotSupportedException(string.Format("不受支持的{0}", op));
}
return(Where(logical));
}