无法在DLL“GetAsncKeyState”中找到名为“user32”的入口点

Question

我试图捕捉所有的键击，我得到并“无法在DLL‘user32’中找到一个名为‘user32’的入口点”，结果= GetAsncKeyState(i)中的错误如下所示

Private Declare Function GetAsncKeyState Lib "user32" (ByVal vkey As Integer) As Integer
Private Sub tmrKeys_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrKeys.Tick
    Dim result As Integer
    Dim key As String
    Dim i As Integer
    For i = 2 To 90
        result = 0
        result = GetAsncKeyState(i)
        If result = -3276 Then
            key = Chr(i)
            If i = 13 Then key = vbNewLine
            Exit For
        End If
    Next i

Answer 1

您描述的错误的原因是因为函数名是GetAsyncKeyState，而不是GetAsyncKeyState。

同样在.NET中，您应该考虑对对如何调用平台调用函数提供更多控制。使用DllImport属性而不是Declare语句(这是一种过时的VB6风格的方法)。

下面是GetAsyncKeyState声明我用的，其中包含了XML文档：

''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Determines whether a key is up or down at the time the function is called, 
''' and whether the key was pressed after a previous call to <see cref="GetAsyncKeyState"/>.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <remarks>
''' <see href="http://msdn.microsoft.com/en-us/library/windows/desktop/ms646310%28v=vs.85%29.aspx"/>
''' </remarks>
''' ----------------------------------------------------------------------------------------------------
''' <param name="vKey">
''' The virtual-key code.
''' <para></para>
''' You can use left- and right-distinguishing constants to specify certain keys.
''' <para></para>
''' See Virtual-Key Codes: 
''' <see href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd375731%28v=vs.85%29.aspx"/>
''' </param>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' If the function succeeds, 
''' the return value specifies whether the key was pressed since the last call to <see cref="GetAsyncKeyState"/>, 
''' and whether the key is currently up or down.
''' <para></para>
''' If the most significant bit is set, the key is down, and if the least significant bit is set, 
''' the key was pressed after the previous call to <see cref="GetAsyncKeyState"/>.
''' <para></para>
''' However, you should not rely on this last behavior.
''' <para></para>
''' <para></para>
''' The return value is zero for the following cases: 
''' <para></para>
''' The current desktop is not the active desktop.
''' <para></para>
''' The foreground thread belongs to another process and the desktop does not allow the hook or the journal record.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<SuppressUnmanagedCodeSecurity>
<DllImport("user32.dll", CharSet:=CharSet.Auto)>
Public Shared Function GetAsyncKeyState(ByVal vKey As System.Windows.Forms.Keys
) As Short
End Function

注意:如果使用preffer，可以将vKey参数更改为Integer数据类型。