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DllImportAttribute Class

Indicates that the attributed method is exposed by an unmanaged dynamic-link library (DLL) as a static entry point.

System.Object
  System.Attribute
    System.Runtime.InteropServices.DllImportAttribute

Namespace:  System.Runtime.InteropServices
Assembly:  mscorlib (in mscorlib.dll)
[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Method, Inherited = false)>]
[<ComVisibleAttribute(true)>]
type DllImportAttribute =  
    class 
        inherit Attribute 
    end

The DllImportAttribute type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDllImportAttributeInitializes a new instance of the DllImportAttribute class with the name of the DLL containing the method to import.
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  NameDescription
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsValueGets the name of the DLL file that contains the entry point.
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  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public fieldSupported by Portable Class LibrarySupported in .NET for Windows Store appsBestFitMappingEnables or disables best-fit mapping behavior when converting Unicode characters to ANSI characters.
Public fieldSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsCallingConventionIndicates the calling convention of an entry point.
Public fieldSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsCharSetIndicates how to marshal string parameters to the method and controls name mangling.
Public fieldSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsEntryPointIndicates the name or ordinal of the DLL entry point to be called.
Public fieldSupported by Portable Class LibrarySupported in .NET for Windows Store appsExactSpellingControls whether the DllImportAttribute.CharSet field causes the common language runtime to search an unmanaged DLL for entry-point names other than the one specified.
Public fieldSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsPreserveSigIndicates whether unmanaged methods that have HRESULT or retval return values are directly translated or whether HRESULT or retval return values are automatically converted to exceptions.
Public fieldSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsSetLastErrorIndicates whether the callee calls the SetLastError Win32 API function before returning from the attributed method.
Public fieldSupported by Portable Class LibrarySupported in .NET for Windows Store appsThrowOnUnmappableCharEnables or disables the throwing of an exception on an unmappable Unicode character that is converted to an ANSI "?" character.
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  NameDescription
Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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You can apply this attribute to methods.

The DllImportAttribute attribute provides the information needed to call a function exported from an unmanaged DLL. As a minimum requirement, you must supply the name of the DLL containing the entry point.

You apply this attribute directly to C# and C++ method definitions; however, the Visual Basic compiler emits this attribute when you use the Declare statement. For complex method definitions that include BestFitMapping, CallingConvention, ExactSpelling, PreserveSig, SetLastError, or ThrowOnUnmappableChar fields, you apply this attribute directly to Visual Basic method definitions.

Note   JScript does not support this attribute. You can use C# or Visual Basic wrapper classes to access unmanaged API methods from JScript programs.

For additional information about using the platform invoke service to access functions in unmanaged DLLs, see Consuming Unmanaged DLL Functions.

NoteNote

The DllImportAttribute does not support marshaling of generic types.

The following code example shows how to use the DllImportAttribute attribute to import the Win32 MessageBox function. The code example then calls the imported method.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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