IsInvalid Property
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SafeHandle.IsInvalid Property

 

When overridden in a derived class, gets a value indicating whether the handle value is invalid.

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

public abstract bool IsInvalid { get; }

Property Value

Type: System.Boolean

true if the handle value is invalid; otherwise, false.

Derived classes must implement the IsInvalid property so that the common language runtime can determine whether critical finalization is required. Derived classes must provide an implementation that suits the general type of handle they support (0 or -1 is invalid). These classes can then be further derived for specific safe handle types.

Unlike the IsClosed property, which reports whether the SafeHandle object has finished using the underlying handle, the IsInvalid property calculates whether the given handle value is always considered invalid. Therefore, the IsInvalid property always returns the same value for any one handle value.

The following example checks if a file was opened successfully. This code example is part of a larger example provided for the SafeHandle class.

// Determine if file is opened successfully.
if (_handle.IsInvalid)
    throw new Win32Exception(Marshal.GetLastWin32Error(), fileName);

SecurityPermission

for permission to call unmanaged code. Security action: LinkDemand. Associated enumeration: SecurityPermissionFlag.UnmanagedCode

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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