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InvalidCastException Class

The exception that is thrown for invalid casting or explicit conversion.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public ref class InvalidCastException : public SystemException

InvalidCastException is thrown if:

  • For a conversion from a Single or a Double to a Decimal, the source value is infinity, Not-a-Number (NaN), or too large to be represented as the destination type.

  • A failure occurs during an explicit reference conversion.

For an explicit reference conversion to be successful, the source value must be nullptr, or the object type referenced by the source argument must be convertible to the destination type by an implicit reference conversion.

For information on conversions supported by the system, see the Convert class. For errors that occur when the destination type can store source type values, but is not large enough to store a specific source value, see OverflowException exception.

The following Microsoft intermediate language (MSIL) instructions throw InvalidCastException

  • castclass

  • refanyval

  • unbox

InvalidCastException uses the HRESULT COR_E_INVALIDCAST, which has the value 0x80004002.

For a list of initial property values for an instance of InvalidCastException, see the InvalidCastException constructors.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0