Evaluation of a user-defined conversion centers on finding the most-specific user-defined conversion operator for the source expression and target type. This determination is broken into several steps:. Once a most-specific user-defined conversion operator has been identified, the actual execution of the user-defined conversion involves up to three steps:.
Evaluation of a user-defined conversion never involves more than one user-defined or lifted conversion operator. In other words, a conversion from type S to type T will never first execute a user-defined conversion from S to X and then execute a user-defined conversion from X to T. A user-defined implicit conversion from an expression E to a type T is processed as follows:.
Find the set of types, D , from which user-defined conversion operators will be considered. Find the set of applicable user-defined and lifted conversion operators, U. This set consists of the user-defined and lifted implicit conversion operators declared by the classes or structs in D that convert from a type encompassing E to a type encompassed by T.
If U is empty, the conversion is undefined and a compile-time error occurs. A user-defined implicit conversion from a type S to a type T exists if a user-defined implicit conversion exists from a variable of type S to T. A user-defined explicit conversion from an expression E to a type T is processed as follows:.
A user-defined explicit conversion from a type S to a type T exists if a user-defined explicit conversion exists from a variable of type S to T.
Nullable conversions permit predefined conversions that operate on non-nullable value types to also be used with nullable forms of those types. Certain nullable conversions are classified as standard conversions and can occur as part of a user-defined conversion.
Evaluation of a nullable conversion based on an underlying conversion from S to T proceeds as follows:. Given a user-defined conversion operator that converts from a non-nullable value type S to a non-nullable value type T , a lifted conversion operator exists that converts from S?
This lifted conversion operator performs an unwrapping from S? A lifted conversion operator has the same implicit or explicit classification as its underlying user-defined conversion operator. The expression does not have a type, but can be implicitly converted to a compatible delegate type. Some lambda expressions may also be implicitly converted to a compatible expression tree type.
Specifically, an anonymous function F is compatible with a delegate type D provided:. This does not apply to anonymous methods, only lambda expressions.
Anonymous functions may influence overload resolution, and participate in type inference. Conversion of an anonymous function to a delegate type produces a delegate instance that references the anonymous function and the possibly empty set of captured outer variables that are active at the time of the evaluation.
When the delegate is invoked, the body of the anonymous function is executed. The code in the body is executed using the set of captured outer variables referenced by the delegate.
The invocation list of a delegate produced from an anonymous function contains a single entry. The exact target object and target method of the delegate are unspecified.
In particular, it is unspecified whether the target object of the delegate is null , the this value of the enclosing function member, or some other object. Conversions of semantically identical anonymous functions with the same possibly empty set of captured outer variable instances to the same delegate types are permitted but not required to return the same delegate instance.
The term semantically identical is used here to mean that execution of the anonymous functions will, in all cases, produce the same effects given the same arguments. This rule permits code such as the following to be optimized. Since the two anonymous function delegates have the same empty set of captured outer variables, and since the anonymous functions are semantically identical, the compiler is permitted to have the delegates refer to the same target method.
Indeed, the compiler is permitted to return the very same delegate instance from both anonymous function expressions. More precisely, evaluation of the lambda expression conversion produces an object structure that represents the structure of the lambda expression itself. Not every lambda expression can be converted to expression tree types. The conversion to a compatible delegate type always exists , but it may fail at compile-time for implementation-specific reasons. Any integral numeric type is implicitly convertible to any floating-point numeric type.
There are no implicit conversions to the byte and sbyte types. There are no implicit conversions from the double and decimal types. There are no implicit conversions between the decimal type and the float or double types.
A value of a constant expression of type int for example, a value represented by an integer literal can be implicitly converted to sbyte , byte , short , ushort , uint , ulong , nint , or nuint , if it's within the range of the destination type:. As the preceding example shows, if the constant value is not within the range of the destination type, a compiler error CS occurs. The following table shows the predefined explicit conversions between the built-in numeric types for which there is no implicit conversion :.
An explicit numeric conversion might result in data loss or throw an exception, typically an OverflowException. When you convert a value of an integral type to another integral type, the result depends on the overflow checking context. In a checked context, the conversion succeeds if the source value is within the range of the destination type.
Otherwise, an OverflowException is thrown. In an unchecked context, the conversion always succeeds, and proceeds as follows:. Here is the issue I am running into regarding floating point to decimal conversion that is, I am certain, a similar problem as the original poster ran into.
These conversion values are returned in floating point double. ToDecimal , or other similar functionality, does NOT work. The specific conversion statement will execute properly, but the SQL update fails with arithmetic overflow "converting numeric value to numeric value". There must be some method of dealing with this because until one can resolve this problem, the currency conversion values from WebServiceX are, in effect, utterly useless.
The Convert. To[X] method will not safeguard you from conversion problems. It does have a better exception reporting but it will not get you where you want to be. The decimal value is limited to 9 decimal places where the double value does not have such a limit. So rounding the double at max 9 decimal places solves your issue also 9 places is enough for all currency values AFAIK.
The biggest number that a decimal can hold in. Net is 79,,,,,,,,, Peter Mortensen Jared Jared 6, 5 5 gold badges 47 47 silver badges 52 52 bronze badges. Add a comment. Active Oldest Votes. Improve this answer. Chris Pietschmann Chris Pietschmann And there i was looking for Convert. For some reason float didn't work for me, but Convert. ToSingle did the trick! You don't even need to cast, it is implicit.
0コメント