[英]VS2010 Code Analysis and CA1800 : Microsoft Performance
我有下面的代码,我知道这不是最佳的。 我运行了代码分析,它给了我警告
CA1800 : Microsoft.Performance : 'customField', a variable, is cast to type 'DateCustomFieldRef' multiple times in method 'Customer.CustomerToUpdat(SearchResult)'. Cache the result of the 'as' operator or direct cast in order to eliminate the redundant castclass instruction.
我真的不知道该怎么办。
CustomFieldRef[] customFields = customer.customFieldList;
for (int f = 3; f < customFields.Length; f++)
{
CustomFieldRef customField = customFields[f];
if (customField is DateCustomFieldRef)
{
DateCustomFieldRef dateField = (DateCustomFieldRef)customField;
if (dateField.internalId != null && dateField.internalId == "created_date")
{
createdDate = dateField.value.ToString();
}
}
if (customField is StringCustomFieldRef)
{
StringCustomFieldRef tradingNameField = (StringCustomFieldRef)customField;
if (businessNameField.internalId != null && businessNameField.internalId == "business_name")
{
businessName = businessNameField.value;
}
}
}
}
有人可以给我一个代码示例或进一步解释它的真正含义吗?
提前致谢。
问题出在如下代码中:
if (customField is DateCustomFieldRef)
{
DateCustomFieldRef dateField = (DateCustomFieldRef)customField;
这些是多个演员表。
更好:
DateCustomFieldRef fieldasDate = customField as DateCustomFieldFRef
if (fieldasDate != null)
{
blablabla using fieldasdate
这避免了多次强制转换。
这意味着您多次(可能很昂贵) customField
变量,并且最好只转换一次。
您可以使用as
运算符来实现这一点,因为as
运算符执行转换并返回所需类型的实例,如果无法将对象转换为所需类型,则返回NULL。
像这样:
DateCustomFieldRef customField = customFields[f] as DateCustomFieldRef; // the as operator returns null if the casting did not succeed (that is, customFields[f] is not a DatecustomFieldRef instance
if (customField != null)
{
DateCustomFieldRef dateField = customField;
if (dateField.internalId != null && dateField.internalId == "created_date")
{
createdDate = dateField.value.ToString();
}
}
else
{
var stringField = customFields[f] as StringCustomFieldRef;
if (stringField != null )
{
StringCustomFieldRef tradingNameField = stringField;
if (businessNameField.internalId != null && businessNameField.internalId == "business_name")
{
businessName = businessNameField.value;
}
}
}
但是,我相信可能存在一个更好的解决方案(尽管我不知道您的项目,也不知道您的代码),但是是否有可能抽象一些东西呢?
也许您有一个CustomField
基类,并且DateCustomFieldRef
和StringCustomFieldRef
继承自该Customfield
基类。 如果是这种情况,您可以在CustomField
基类中创建一个虚拟(甚至可能是抽象的)方法,该方法在每个子类中均会被覆盖,实际上将返回该字段的值。
像这样:
public class CustomField<T>
{
public string Internalid
{
get;
set;
}
public T Value
{
get;
set;
}
public virtual string GetStringRepresentation()
{
return Value.ToString();
}
}
public class DateCustomField : CustomField<DateTime>
{
public override string GetStringRepresentation()
{
return Value.ToShortDateString();
}
}
然后,您的代码可以看起来更加简单:
foreach( CustomField f in customFields )
{
if( f.InternalId == "created_date" )
{
createdDate = f.GetStringRepresentation();
}
if( f.InternalId == "business_name" )
{
businessName = f.GetStringRepresentation();
}
}
(可以使上面的代码更简单,更简洁,但是您会逐渐感到困惑。)
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.