Error message Nullable object must have a value

Question

I have a null error on my DTO object at runtime: I didn't understand because column is nullable: ``` [DataContract] public class SearchParametersCompanyDTO { public SearchParametersCompanyDTO(); [DataMember] public CompanyColumnsEnumDTO? Column { get; set; } [DataMember] public int PageIndex { get; set; } [DataMember] public int PageSize { get; set; } [DataMember] public string Term { get; set; } } [DataContract] public enum CompanyColumnsEnumDTO { [EnumMember] CompanyName = 0, [EnumMember] City = 1, [EnumMember] PostCode = 2, } ``` It must be a conversion problem because null is accepted on Column: ``` var dto = new SearchParametersCompanyDTO { PageIndex = pageIndex, PageSize = defaultPageSize, Term = term, Column = null }; ``` Any idea?

Accepted Answer

You're trying to cast a null value to an enum type (rather than a nullable enum type). I'm guessing you actually want to change your cast to:

```
Column = (CompanyColumnsEnumDTO?) column
```

Error message Nullable object must have a value

Solution

Problem