SYSK 283: Use Caution When Using ‘Short’ Data Type in Enumerated Types
Consider the following innocent looking code:
[System.Runtime.Serialization.DataContract]
public enum TestEnum : short
{
[System.Runtime.Serialization.EnumMember] Undefined = 0,
[System.Runtime.Serialization.EnumMember] TestType1 = 1,
[System.Runtime.Serialization.EnumMember] TestType2 = 2,
}
[System.Runtime.Serialization.DataContract]
public class TestData
{
private TestEnum _test = TestEnum.Undefined;
[System.Runtime.Serialization.DataMember]
public TestEnum Test
{
get { return _test; }
set { _test = value; }
}
}
Do you see any problems with it? Notice that TestEnum values are defined as short, not the default (integer) data type…
While the System.Runtime.Serialization.DataContractSerializer will serialize/de-serialize an instance of TestData class without any problems, System.Web.Script.Serialization.JavaScriptSerializer will throw an exception -- "Specified cast is not valid."
Try it yourself:
TestData d1 = new TestData();
d1.Test = TestEnum.TestType1;
System.Web.Script.Serialization.JavaScriptSerializer js = new System.Web.Script.Serialization.JavaScriptSerializer();
string x = js.Serialize(d1);
Note: change the TestEnum to be int, and the problem is gone…
