C# Signature:

[DllImport("mpr.dll")]
static extern int WNetCancelConnection2(string lpName, Int32 dwFlags, bool bForce);

VB Signature:

Declare Function WNetCancelConnection2 Lib "mpr.dll" Alias "WNetCancelConnection2A" (ByVal lpName As String, ByVal dwFlags As Long, ByVal fForce As Long) As Long

Notes:

VB SIG

    ''' <summary>
    ''' The WNetCancelConnection2 function cancels an existing network connection.
    ''' You can also call the function to remove remembered network connections that are not currently connected.
    ''' </summary>
    ''' <param name="lpName"></param>
    ''' <param name="dwFlags"></param>
    ''' <param name="fForce"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    <DllImport("mpr.dll")> _
    Private Shared Function WNetCancelConnection2(ByVal lpName As String, _
                          ByVal dwFlags As Long, _
                          ByVal fForce As Long) As Long
    End Function

Tips & Tricks:

The system updates the user profile with the information that the connection is no longer a persistent one if you pass this constant as <dwFlags>

private const int CONNECT_UPDATE_PROFILE = 0x1;

Sample Code:

[DllImport("mpr.dll")]
public static extern int WNetCancelConnection2(string lpName, Int32 dwFlags, bool fForce);
private const int CONNECT_UPDATE_PROFILE = 0x1;
private const int NO_ERROR = 0;

int result=WNetCancelConnection2("Y:", CONNECT_UPDATE_PROFILE, true);
if (result != NO_ERROR) {
//handle error
}

Alternative Managed API:

Do you know one? Please contribute it!