Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
537 views
in Technique[技术] by (71.8m points)

c# - How to use Convert.ChangeType() when conversionType is a nullable int

I mean, I want to convert this:

string a = 24;
Convert.ChangeType(a, typeof(decimal?))

But it throws me an error.

UPDATE 1:

I've got a Type object where can be decimal?, int?, .. many nullable types. Then with the Type object, I need to convert the string value in type object.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

See an excellent answer here:

public static T GetValue<T>(string value)
{
   Type t = typeof(T);
   t = Nullable.GetUnderlyingType(t) ?? t;

   return (value == null || DBNull.Value.Equals(value)) ? 
      default(T) : (T)Convert.ChangeType(value, t);
} 

E.g.:

string a = 24;
decimal? d = GetValue<decimal?>(a);

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...