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Is null check needed before calling instanceof?
...lue of the RelationalExpression is
not null and the reference could be
cast to the ReferenceType
without raising a ClassCastException.
Otherwise the result is false."
So if the operand is null, the result is false.
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How to get the error message from the error code returned by GetLastError()?
... pointer? But passing it the pointer's address (pointer-to-a-pointer), but casting it to a regular pointer... Win32 weirdness. Thanks for the heads up, fixed it in my own code base (and my answer). Very subtle catch.
– Jamin Grey
Jan 11 '14 at 1:45
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SQL Data Reader - handling Null column values
...sqlreader[indexAge] as int? ?? default(int);
The as operator handles the casting including the check for DBNull.
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How to use performSelector:withObject:afterDelay: with primitive types in Cocoa?
...trick if it is a BOOL parameter.
Pass nil for NO and self for YES. nil is cast to the BOOL value of NO. self is cast to the BOOL value of YES.
This approach breaks down if it is anything other than a BOOL parameter.
Assuming self is a UIView.
//nil will be cast to NO when the selector is perform...
Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '=
...s not suffer of performance issues.
Using Option 1 and 2, aka the COLLATE cast approach, can lead to potential bottleneck, cause any index defined on the column will not be used causing a full scan.
Even though I did not try out Option 3, my hunch is that it will suffer the same consequences of op...
Is there a Python equivalent to Ruby's string interpolation?
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@Caste see here: docs.python.org/library/stdtypes.html#string-formatting and post a follow up comment if you need any more details
– mikej
Dec 15 '10 at 13:59
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Passing a single item as IEnumerable
...f you pass in a list or an array, then an unscrupulous piece of code could cast it and change the contents, leading to odd behaviour in some situations. You could use a read-only collection, but that's likely to involve even more wrapping. I think your solution is as neat as it gets.
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What is a raw type and why shouldn't we use it?
... String name = (String) o;
System.out.println(name);
} // throws ClassCastException!
// java.lang.Boolean cannot be cast to java.lang.String
Now we run into trouble at run-time, because names contains something that isn't an instanceof String.
Presumably, if you want names to contain only...
Cannot create an array of LinkedLists in Java…?
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For some reason you have to cast the type and make the declaration like this:
myMatrix = (LinkedList<IntegerNode>[]) new LinkedList<?>[numRows];
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How to do ToString for a possibly null object?
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C# 6.0 Edit:
With C# 6.0 we can now have a succinct, cast-free version of the orignal method:
string s = myObj?.ToString() ?? "";
Or even using interpolation:
string s = $"{myObj}";
Original Answer:
string s = (myObj ?? String.Empty).ToString();
or
string s = (myObjc ?? "")....