Given the following piece of foreach code how do I write it as a LINQ
foreach(var error in ex.Errors)
{
Logger.Error("Field {0} has an error : {1}. for SSN {2}",error.FieldName, error.Message, error.SSN);
}
3 Answers
LINQ is for producing results, such as new sequences and aggregates. It is not a good fit for producing side effects, such as log outputs.
The foreach loop in your code is a perfectly acceptable, very readable solution. If you would like to get rid of it anyway, you could use List.ForEach method, which takes an Action<T>:
ex.Errors.ForEach(
error => Logger.Error(
"Field {0} has an error : {1}. for SSN {2}"
, error.FieldName
, error.Message
, error.SSN);
);
answered Jan 25, 2016 at 16:36
Sergey Kalinichenko
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1 Comment
Pete Garafano
not always as clear as using a dedicated
foreach loop, but I have used this before myself.I personally would not do this, but if you really want to use LINQ here, there are two options:
ex.Errors.ForEach(error => Logger.Error("Field {0} has an error : {1}. for SSN {2}", error.FieldName, error.Message, error.SSN));
or
Logger.Error(string.Join(Environment.NewLine,
ex.Errors.Select(error =>
string.Format("Field {0} has an error : {1}. for SSN {2}", error.FieldName, error.Message, error.SSN))));
But the second one depends a little on how your Logger.Error is implemented and if it's ok to join the strings.
Comments
You can convert to list and use ForEach
ex.Errors.ToList().ForEach(error =>
{
Logger.Error("Field {0} has an error : {1}. for SSN {2}", error.FieldName, error.Message, error.SSN);
});
Alternatively, write your own ForEach extension method:
public static void ForEach<T>(this IEnumerable<T> enumeration, Action<T> action)
{
foreach(T item in enumeration)
{
action(item);
}
}
But in this case is probably better don't using Linq.
foreachhere, you could use theList<T>.ForEach(Action<T>)to do the same, it is more obscure though