C# Signature:

[DllImport("user32.dll")]
static extern IntPtr GetKeyboardLayout(uint idThread);

VB.NET Signature:

Public Declare Function GetKeyboardLayout Lib "user32" (ByVal idThread As UInteger) As IntPtr

User-Defined Types:

None.

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

///For using "imm32.dll"'s functions.

const int GCL_REVERSECONVERSION = 0x0002;

[DllImport("Imm32.dll")]
public static extern IntPtr ImmGetContext(IntPtr hWnd);

[DllImport("User32.dll")]
public static extern IntPtr GetKeyboardLayout(int idThread);

[DllImport("Imm32.dll")]
public static extern int ImmGetConversionList(
    IntPtr hKL,
    IntPtr hIMC,
    string lpSrc,
    IntPtr lpDst,
    int dwBufLen,
    int uFlag          
    );

[DllImport("Imm32.dll")]
public static extern bool ImmReleaseContext(IntPtr hWnd,IntPtr hIMC);

[StructLayout(LayoutKind.Sequential)]
public class CANDIDATELIST
{
    public int  dwSize;      
    public int  dwStyle;      
    public int  dwCount;      
    public int  dwSelection;  
    public int  dwPageStart;  
    public int  dwPageSize;  
    public int  dwOffset;  
}

public string[] GetReverseConversion(string AText)
{
    string[] strList = null;
    if (AText.Length > 0)
    {
    IntPtr hIMC = ImmGetContext(this.Handle);
    IntPtr hKL = GetKeyboardLayout(0);
    int dwSize = ImmGetConversionList(hKL,hIMC,AText,IntPtr.Zero,0,GCL_REVERSECONVERSION);
    if (dwSize > 0)
    {
        IntPtr BufList = Marshal.AllocHGlobal(dwSize);
        try
        {
        ImmGetConversionList(hKL,hIMC,AText,BufList,dwSize,GCL_REVERSECONVERSION);
        CANDIDATELIST list = new CANDIDATELIST();
        Marshal.PtrToStructure(BufList,list);
        byte[] buf = new byte[dwSize];
        Marshal.Copy(BufList,buf,0,dwSize);
        Marshal.FreeHGlobal(BufList);
        int os = list.dwOffset;
        string str = System.Text.Encoding.Default.GetString(buf,os,buf.Length-os-3);
        char[] par = "\0".ToCharArray();
        strList = str.Split(par);
        }
        finally
        {
        ImmReleaseContext(this.Handle,hIMC);
        }
    }
    }
    return strList;
}

///The example of use of the above code

private void button1_Click(object sender, System.EventArgs e)
{
    listBox1.Items.Clear();
    listBox1.Items.AddRange(GetReverseConversion(textBox1.Text));
}

Alternative Managed API:

Do you know one? Please contribute it!