Null

[shapper]

Hello,

I have a method as follows:

public static bool Check(string value) {

And I am calling it:

Rule.Check(User.Level.Value.ToString() ?? "")

Where Level is of type Enum UserLevel:

public UserLevel? Level { get; set; }

When I call the method Check I get an error:
Nullable object must have a value.

I tried to add ?? "" but it is not working.

I know that in this case User.Level is null.

What am I doing wrong?

Thanks,
Miguel

 

[Family Tree Mike]

Hello,

I have a method as follows:

public static bool Check(string value) {

And I am calling it:

Rule.Check(User.Level.Value.ToString() ?? "")

Where Level is of type Enum UserLevel:

public UserLevel? Level { get; set; }

When I call the method Check I get an error:
Nullable object must have a value.

I tried to add ?? "" but it is not working.

I know that in this case User.Level is null.

What am I doing wrong?

Thanks,
Miguel

Try calling Rule.Check(User.Level == null ? "" :
User.Level.Value.ToString()).

The problem is that you are calling .Value on a null (User.Level).

 

[Alexander Myachin]

User.Level.ToString() ??

 

[Göran Andersson]

Hello,

I have a method as follows:

public static bool Check(string value) {

And I am calling it:

Rule.Check(User.Level.Value.ToString() ?? "")

Where Level is of type Enum UserLevel:

public UserLevel? Level { get; set; }

When I call the method Check I get an error:
Nullable object must have a value.

I tried to add ?? "" but it is not working.

I know that in this case User.Level is null.

What am I doing wrong?

Thanks,
Miguel

The nullable variable has a HasValue property that you can use to
determine if there is a value or not. If there is no value, using the
Value property causes an exception.

Rule.Check(User.Level.HasValue ? User.Level.Value.ToString() : string.Empty)