请教：我设置了开机密码但是无法弹出软键盘

Imports System.Runtime.InteropServices
Public Class SipClass
#Region "API"
    <DllImport("coredll.dll", CharSet:=CharSet.Unicode, SetLastError:=True)> _
    Private Shared Function SipShowIM(ByVal dwFlag As SIPStatus) As Integer
    End Function
    <DllImport("coredll.dll", CharSet:=CharSet.Unicode, SetLastError:=True)> _
    Private Shared Function SipSetInfo(ByRef pSipInfo As SIPINFO) As Boolean
    End Function
    <DllImport("coredll.dll", CharSet:=CharSet.Unicode, SetLastError:=True)> _
    Private Shared Function SipGetInfo(ByRef pSipInfo As SIPINFO) As Boolean
    End Function
#End Region
#Region "枚举"
    Private Enum SIPStatus
        SIPF_OFF = 0
        SIPF_ON
    End Enum
#End Region
#Region "结构"
    Private Structure SIPINFO
        Public CbSize As Integer
        Public FdwFlags As SIPStatus
        Public RcVisibleDesktop As RECT
        Public RcSipRect As RECT
        Public DwImDataSize As Integer
        Public PvImData As Integer
    End Structure
    Private Structure RECT
        Public Left As Integer
        Public Top As Integer
        Public Right As Integer
        Public Bottom As Integer
        Public ReadOnly Property Width() As Integer
            Get
                Return Right - Left
            End Get
        End Property
        Public ReadOnly Property Height() As Integer
            Get
                Return Bottom - Top
            End Get
        End Property
    End Structure
#End Region
#Region "公共方法"
    ''' <summary>
    ''' 显示输入面板
    ''' </summary>
    ''' <remarks></remarks>
    Public Shared Function Show() As Boolean
        Return SipShowIM(SIPStatus.SIPF_ON)
    End Function
    ''' <summary>
    ''' 影藏输入面板
    ''' </summary>
    ''' <remarks></remarks>
    Public Shared Function Hide() As Boolean
        Return SipShowIM(SIPStatus.SIPF_OFF)
    End Function
    ''' <summary>
    ''' 显示输入面板,并设定面板的位置
    ''' </summary>
    ''' <param name="Location"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function SetPosition(ByVal Location As Point) As Boolean
        Dim mySi As SIPINFO
        mySi.CbSize = Marshal.SizeOf(GetType(SIPINFO))
        Call SipGetInfo(mySi)
        mySi.RcSipRect.Top = Location.Y
        mySi.RcSipRect.Bottom = Location.Y + mySi.RcSipRect.Height
        mySi.RcSipRect.Left = Location.X
        mySi.RcSipRect.Right = Location.X + mySi.RcSipRect.Width
        mySi.FdwFlags = SIPStatus.SIPF_ON
        Return SipSetInfo(mySi)
    End Function
#End Region
End Class