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Direct casting vs 'as' operator?
...
string s = (string)o; // 1
Throws InvalidCastException if o is not a string. Otherwise, assigns o to s, even if o is null.
string s = o as string; // 2
Assigns null to s if o is not a string or if o is null. For this reason, you cannot use it with value types (th...
Unable to cast object of type 'System.DBNull' to type 'System.String`
... There are several scenarios where you might prefer convert to an explicit cast. @romanm noted one of them. Another one is when you work with decimals and care about the different rounding mechanisms that Convert.ToInt32 and (int) use. The former rounds to the nearest even value, while the explicit ...
Ignore Typescript Errors “property does not exist on value of type”
...erHtmlElement.getBBox();
###Edit, late 2016
Since TypeScript 1.6 prefered casting operator is as those lines can be squashed into:
let coordinates = (outerElement[0] as any).getBBox();
###Other solutions
Of course if you'd like to do it right, which is an overkill sometimes, you can:
Create own i...
error: cannot dynamic_cast ‘b’ (of type ‘class Base*’) to type ‘c...
error: cannot dynamic_cast ‘b’ (of type ‘class Base*’) to type ‘class Derived*’ (source type is not polymorphic)在将父类型转换为子类型时,可以使用static_cast和dynamic_cast.如果使用dynamic_cast,它要求父类必须为多态的,即要求至少有一个虚函数,因此....
What is a void pointer in C++? [duplicate]
... it stores which kinds of objects, and therefore which type you can safely cast it to.
This construct is nothing like dynamic or object in C#. Those tools actually know what the original type is; void* does not. This makes it far more dangerous than any of those, because it is very easy to get it ...
Return Boolean Value on SQL Select Statement
...N EXISTS (
SELECT *
FROM [User]
WHERE UserID = 20070022
)
THEN CAST(1 AS BIT)
ELSE CAST(0 AS BIT) END
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Converting stream of int's to char's in java
...et, or use InputStreamReader with the appropriate Charset instead.
Simply casting from int to char only works if you want ISO-8859-1, if you're reading bytes from a stream directly.
EDIT: If you are already using a Reader, then casting the return value of read() to char is the right way to go (aft...
What's Mongoose error Cast to ObjectId failed for value XXX at path “_id”?
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Mongoose's findById method casts the id parameter to the type of the model's _id field so that it can properly query for the matching doc. This is an ObjectId but "foo" is not a valid ObjectId so the cast fails.
This doesn't happen with 41224d776a326...
How to convert a double to long without casting?
What is the best way to convert a double to a long without casting?
9 Answers
9
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Downcasting in Java
Upcasting is allowed in Java, however downcasting gives a compile error.
11 Answers
1...