是否有尝试Convert.ToInt32 ...避免异常 [英] Is there a try Convert.ToInt32... avoiding exceptions
问题描述
我想知道是否存在将对象转换为 int
的安全方法,避免出现异常。
我正在寻找类似 public static bool TryToInt32(object value,out int result);
$ b $的东西b
我知道我可以做这样的事情:
public static bool TryToInt32(对象值,出int结果)
{
try
{
结果= Convert.ToInt32(值);
返回true;
}
catch
{
结果= 0;
返回false;
}
}
但我宁愿避免出现异常,因为它们
我认为这比较优雅,但仍然便宜:
公共静态布尔TryToInt32(对象值,输出为int结果)
{
if(value == null)
{
result = 0;
返回false;
}
返回int.TryParse(value.ToString(),超出结果);
}
有人有更好的主意吗?
更新:
这听起来有点像割头发,但是将对象转换为字符串会强制实现者创建清晰的 ToString ()
函数。例如:
public class百分比
{
public int Value {get;组; }
公共替代字符串ToString()
{
返回string.Format( {0}%,Value);
}
}
百分比p =新的Percentage();
p.Value = 50;
int v;
if(int.TryParse(p.ToString(),out v))
{
}
这是错误的,我可以在这里做两件事,或者像这样实现 IConvertable
:
公共静态布尔值ToInt32(对象值,输出结果为int)
{
if(value == null)
{
结果= 0;
返回false;
}
if(值是IConvertible)
{
结果=((IConvertible)value).ToInt32(Thread.CurrentThread.CurrentCulture);
返回true;
}
返回int.TryParse(value.ToString(),超出结果);
}
但是 ToInt32
IConvertible
的方法无法取消。因此,如果无法转换该值,则无法避免异常。
或者两个:有没有一种方法可以检查对象是否包含隐式运算符? p>
这非常糟糕:
if(value.GetType()。 GetMethods()。FirstOrDefault(方法=>方法。名称== op_Implicit&&方法.ReturnType == typeof(int))!= null)
{
结果=(int)值;
返回true;
}
int变量= 0;
int.TryParse(stringValue,out变量);
如果无法解析,则变量为0。请参见 http://msdn.microsoft.com/en-us/library/f02979c7.aspx
I'd like to know if there is a "safe" way to convert an object to an int
, avoiding exceptions.
I'm looking for something like public static bool TryToInt32(object value, out int result);
I know I could make something like this:
public static bool TryToInt32(object value, out int result)
{
try
{
result = Convert.ToInt32(value);
return true;
}
catch
{
result = 0;
return false;
}
}
But I'd rather avoid exceptions, because they are slowing down the process.
I think this is more elegant, but it's still "cheap":
public static bool TryToInt32(object value, out int result)
{
if (value == null)
{
result = 0;
return false;
}
return int.TryParse(value.ToString(), out result);
}
Does anyone have better ideas?
UPDATE:
This sounds a little like splitting hairs, but converting an object to string forces the implementer to create a clear ToString()
function. For example:
public class Percentage
{
public int Value { get; set; }
public override string ToString()
{
return string.Format("{0}%", Value);
}
}
Percentage p = new Percentage();
p.Value = 50;
int v;
if (int.TryParse(p.ToString(), out v))
{
}
This goes wrong, I can do two things here, or implement the IConvertable
like this:
public static bool ToInt32(object value, out int result)
{
if (value == null)
{
result = 0;
return false;
}
if (value is IConvertible)
{
result = ((IConvertible)value).ToInt32(Thread.CurrentThread.CurrentCulture);
return true;
}
return int.TryParse(value.ToString(), out result);
}
But the ToInt32
method of the IConvertible
cannot be canceled. So if it's not possible to convert the value, an exception cannot be avoided.
Or two: Is there a way to check if the object contains a implicit operator?
This is very poor:
if (value.GetType().GetMethods().FirstOrDefault(method => method.Name == "op_Implicit" && method.ReturnType == typeof(int)) != null)
{
result = (int)value;
return true;
}
int variable = 0;
int.TryParse(stringValue, out variable);
If it can't be parsed, the variable will be 0. See http://msdn.microsoft.com/en-us/library/f02979c7.aspx
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