C#•16mo ago

✅ Converting value to nullable

I've got a point in my code where I've got:

int intValue = 5;
object? value = intValue; // contains a non-nullable value, an int, float, etc
Type type = typeof(int?);

value = ChangeType(value, type);

int intValue = 5;
object? value = intValue; // contains a non-nullable value, an int, float, etc
Type type = typeof(int?);

value = ChangeType(value, type);

I need to write ChangeType, and only have access to value and type. Using Convert.ChangeType() doesn't work here, and throws an exception. How can I convert this value to nullable successfully? Thanks

10 Replies

Aaron•16mo ago

you can't you can never have a boxed nullable

Hugh•16mo ago

ahh shit... okay

Pobiega•16mo ago

int val = 123;
object? nullable = new int?(val);

int val = 123;
object? nullable = new int?(val);

Hugh•16mo ago

I don't know that it's int at that point

Aaron•16mo ago

that just gets boxed as an int

Hugh•16mo ago

I can re-work some other code further up the chain to make this work

Aaron•16mo ago

if the Nullable has no value, when you box it, it gives you a literal null

Pobiega•16mo ago

I'm not sure what the goal here is

MODiX•16mo ago

Windows10CE#8553

REPL Result: Success

int? i = null;
object? o = i;
object.ReferenceEquals(o, null)

int? i = null;
object? o = i;
object.ReferenceEquals(o, null)

Result: bool

True

True

Compile: 493.959ms | Execution: 36.655ms | React with ❌ to remove this embed.

Hugh•16mo ago

If this isn't possible, then I've got another approach that I can try here Thanks both

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✅ Converting value to nullable