I'm a C# programmer but am converting some code from C# to VB.NET. In c# I can simply use (int)blah.getValue() where getValue() returns an Integer?
Doing a DirectCast() in VB.NET doesn't work though, saying Integer? cannot be converted to Integer.
Ideas?
Use the value property to get the actual integer value.
Dim intNullable As Integer?
If intNullable.HasValue Then
Return intNullable.Value
End If
InvalidOperationException "Nullable object must have a value." That's what happens when the C# (int) cast encounters a null value.
Integer? is a nullable type, so you may have to convert it to a nullable Integer.
You want to use CType function like so, 'Integer' or 'Integer?' Depending on your situation
Val = CType(Source,Integer?)
CInt(ValueToBeInteger)
If you use CType or CInt or another conversion function to convert the nullable integer to a regular integer, a null value will be converted to zero.
Check to see if the nullable type has a value as in @Rhapsody 's answer.
You can also use the nullable type methods .GetValueOrDefault() and .GetValueOrDefault(x). The overload without any parameters returns the default value of the datatype if the value is null. E.g. Integer default value is zero; Boolean default value is False. The overload with a parameter allows you to specify a default value to use if the value is null.
myNonNullableVar = if(myNullableVar, 0)
will set 0 if integer? is null or return the actual value.
In C#, it would be:
myNonNullableVar = myNullableVar ?? 0;
dim a as integer? = 1
dim b as integer = a.value
Remember to check if a.hasvalue (returns boolean, true if a has value).
@SLC: It is very simple to get values of Nullable Int32? of C# into Integer.
Example:
ID(Nullable<Int32?>)
You have to do: ID.value
where ID is a NullableObject.
And it will return an integer in VB.NET.
Nullable<Int32?> makes no sense. Perhaps you meant to type Nullable<Int32> (without the question mark)?
getValue()returnsInteger?, then the.Valueproperty is of type Integer. Just useblah.getValue().Value. Or also useblah.getValue().GetValueOrDefault(<default value here>)