Expression.Convert Method (Expression, Type, MethodInfo)
Creates a UnaryExpression that represents a conversion operation for which the implementing method is specified.
Assembly: System.Core (in System.Core.dll)
public static UnaryExpression Convert( Expression expression, Type type, MethodInfo method )
- Type: System.Linq.Expressions.Expression
An Expression to set the Operand property equal to.
expression or type is null.
method is not null and the method it represents returns void, is not static (Shared in Visual Basic), or does not take exactly one argument.
No conversion operator is defined between expression.Type and type.
expression.Type is not assignable to the argument type of the method represented by method.
The return type of the method represented by method is not assignable to type.
expression.Type or type is a nullable value type and the corresponding non-nullable value type does not equal the argument type or the return type, respectively, of the method represented by method.
More than one method that matches the method description was found.
The following rules determine the implementing method for the operation:
If method is not null, it is the implementing method. It must represent a non-void, static (Shared in Visual Basic) method that takes one argument.
Otherwise, if either expression.Type or type is a user-defined type that defines an implicit or explicit conversion operator, the MethodInfo that represents that operator is the implementing method.
If both expression.Type and type represent numeric or Boolean types, or nullable or non-nullable enumeration types, the implementing method is null.
If either expression.Type or type is a reference type and an explicit boxing, unboxing, or reference conversion exists from expression.Type to type, the implementing method is null.
Lifted versus Non-Lifted
If the implementing method is not null:
If expression.Type is assignable to the argument type of the implementing method and the return type of the implementing method is assignable to type, the node is not lifted.
If either or both of expression.Type or type are a nullable value type and the corresponding non-nullable value types are equal to the argument type and the return type of the implementing method respectively, the node is lifted.
If the implementing method is null:
If both expression.Type and type are non-nullable, the node is not lifted.
Otherwise the node is lifted.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.