C# Signature:

    [DllImport("mpr.dll", CharSet=CharSet.Auto, SetLastError=true)]
    public static extern int WNetGetConnection([MarshalAs(UnmanagedType.LPTStr)] string localName, [MarshalAs(UnmanagedType.LPTStr)] StringBuilder remoteName, ref int length);

VB Signature:

    ''' <summary>
    ''' Use to get UNC Path of a Mapped Drive
    ''' </summary>
    ''' <param name="localName"></param>
    ''' <param name="remoteName"></param>
    ''' <param name="length"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    <DllImport("mpr.dll")> _
    Shared Function WNetGetConnection(<MarshalAs(UnmanagedType.LPTStr)> _
                      ByVal localName As String, ByVal remoteName As System.Text.StringBuilder, _
                      ByRef length As Integer) As Integer
    End Function

Alternative VB Signature:

    Declare Function WNetGetConnection Lib "mpr.dll" Alias "WNetGetConnectionA" (ByVal localName As String, ByVal remoteName As System.Text.StringBuilder, ByRef length As Integer) As Integer

User-Defined Types:

None.

Notes:

localName is the local name for the network resource (drive or printer)

remoteName is a string builder used to return the network name for the resource

length is the current capacity of the StringBuilder

If the call fails because the StringBuilder is not large enough, the call will return a value of 234, and the Length parameter will contain the required size.

Tips & Tricks:

Please add some!

Sample Code:

// This sample code assumes you currently have a drive mapped to p:

// Find out what remote device a local mapping is to

int rc=0;

// Size for the buffer we will use

int bsize=200;

// Create a new stringbuilder, pre-sized as above

StringBuilder rname = new StringBuilder(bsize);

// Call the function

rc = WNetGetConnection("p:", rname, ref bsize);

Sample Code for Visal Basic 2005 Express Edition:

(Without any Error-Handling)

    Declare Function WNetGetConnection Lib "mpr.dll" Alias "WNetGetConnectionA" (ByVal localName As String, _
    ByVal remoteName As System.Text.StringBuilder, ByRef length As Integer) As Integer

    Private Function strToUnc(ByVal path As String)
        Dim length As Integer = 255
        Dim UNC As New System.Text.StringBuilder(length)
        WNetGetConnection(Microsoft.VisualBasic.Left(path, 2), UNC, length)
        Return UNC.ToString
    End Function

    'to get the UNC-Path of a network-drive use something like:
    Private Sub Test()
        Dim dr As String = "J:\"
        MsgBox("The UNC-Path of drive " & dr & " is: " & strToUnc(dr))
    End Sub

Sample Code for VB.NET with error handling:

Declare Function WNetGetConnection Lib "mpr.dll" Alias "WNetGetConnectionA" _
                      (ByVal localName As String, _
                      ByVal remoteName As System.Text.StringBuilder, _
                      ByRef length As Integer) As Integer

Private Sub DisplayUncPath(ByVal aLocalPath As String)

    Dim theDriveName As String = aLocalPath.Substring(0, aLocalPath.IndexOf(":") + 1)
    If theDriveName <> "" Then
        Dim theDriveInfo As New DriveInfo(theDriveName)
        If theDriveInfo.DriveType = DriveType.Network Then
        Dim uncPathBuf As New StringBuilder(259)
        Dim err As Integer = WNetGetConnection(theDriveName, uncPathBuf, uncPathBuf.Capacity)
        If err = 0 Then
            Dim pathname As String = uncPathBuf.ToString()
            MessageBox.Show(aLocalPath.Replace(theDriveName, pathname))
        Else
            MessageBox.Show("Failed with error :" & err)
        End If
        Else
        MessageBox.Show(theDriveName & " is not a network mapped path.")
        End If
      End If
End Sub

Alternative Managed API:

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