DllImportAttribute(String) Constructor

Definition

Namespace:

System.Runtime.InteropServices

Assembly:

System.Runtime.InteropServices.dll

Source:

DllImportAttribute.cs

Initializes a new instance of the DllImportAttribute class with the name of the DLL containing the method to import.

public:
 DllImportAttribute(System::String ^ dllName);

public DllImportAttribute (string dllName);

new System.Runtime.InteropServices.DllImportAttribute : string -> System.Runtime.InteropServices.DllImportAttribute

Public Sub New (dllName As String)

Parameters

dllName

String

The name of the DLL that contains the unmanaged method. In .NET Framework, this can include an assembly display name, if the DLL is included in an assembly.

Examples

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.

using System;
using System.Runtime.InteropServices;

class Example
{
    // Use DllImport to import the Win32 MessageBox function.
    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
    public static extern int MessageBox(IntPtr hWnd, String text, String caption, uint type);
    
    static void Main()
    {
        // Call the MessageBox function using platform invoke.
        MessageBox(new IntPtr(0), "Hello World!", "Hello Dialog", 0);
    }
}

Imports System.Runtime.InteropServices

Module Example

    ' Use DllImport to import the Win32 MessageBox function.
    <DllImport("user32.dll", CharSet:=CharSet.Unicode)> _
    Function MessageBox(ByVal hwnd As IntPtr, ByVal t As String, ByVal caption As String, ByVal t2 As UInt32) As Integer
    End Function


    Sub Main()
        ' Call the MessageBox function using platform invoke.
        MessageBox(New IntPtr(0), "Hello World!", "Hello Dialog", 0)
    End Sub

End Module

Remarks

.NET Framework only: If an unmanaged DLL file is included in an assembly, for example, by using the linker or the /linkresource compiler option, you can specify the assembly display name as part of dllName. For example, if an unmanaged DLL named unmanaged.dll is included in a managed assembly named MyAssembly, the attribute might be specified as shown in the following code.

[DllImport("unmanaged.dll, MyAssembly, Version= 1.0.0.0,"
    "Culture=neutral, PublicKeyToken=a77e0ba5eab10125")]
int SomeFuncion1(int parm);

[DllImport("unmanaged.dll, MyAssembly, Version= 1.0.0.0," +
    "Culture=neutral, PublicKeyToken=a77e0ba5eab10125")]
internal static extern int SomeFuncion1(int parm);

<DllImport("unmanaged.dll, MyAssembly, Version= 1.0.0.0," +
    "Culture=neutral, PublicKeyToken=a77e0ba5eab10125")>
Friend Shared Function DummyFuncion1(parm As Integer) As Integer
End Function