What causes exception in string.concat
- by Budda
Here are few classes:
public class MyItem : ParamOut
{
public string Code
{
get { return _quoteCode; }
}
public InnerItem[] Skus
{
get { return _skus; }
}
public PriceSummary Price
{
get { return _price; }
}
public override string ToString()
{
return string.Concat("Code=", Code, "; SKUs=[", Skus != null ? "{" + string.Join("},{", Array.ConvertAll(Skus, item => item.ToString())) + "}" : "", "]"
, "; Price={", Price.ToString(), "}", base.ToString()
);
}
...
}
public abstract class ParamOut
{
public override string ToString()
{
return null;
}
public string ErrorMessage { get; set; }
}
Here is calling functionality:
{
MyItem item = new MyItem{ ErrorMessage = "Bla-bla-bla" };
string text = item.ToString();
}
I am getting NullReference exception inside of 'ToString()' method (each property of item variable is null).
Question:
Q1. what overload of string.Concat will be called in this case? I have 9 parameters, so I guess one of the following:
public static string Concat(params Object[] args)
or
public static string Concat(params string[] values)
But which of them?
Q2. Why exception is generated? Shouldn't 'null' be converted into something like 'null' or "" (empty string)?
Thanks a lot!
