无法在DLL中找到以函数命名的入口点？

Question

在C ++ DLL中：

struct APP_PARAM
{
    int numData;
    LPCSTR *text;
    int *values;
};

int App::StartApp(APP_PARAM params)
{
    for (int i = 0; i < numLines; i++)
    {
        OutputDebugString(params.text[i]);
    }
}

在VB.NET中：

<StructLayoutAttribute(LayoutKind.Sequential)> _
  Public Structure APP_PARAM
    Public numData As Integer
    Public text As System.IntPtr
    Public values As System.IntPtr
  End Structure

  Declare Function StartApp Lib "AppSupport.dll" (ByVal params As APP_PARAM) As Integer

  Sub Main()

    Dim params As APP_PARAM
    params.numData = 3

    Dim text As String() = {"A", "B", "C"}
    Dim textHandle As GCHandle = GCHandle.Alloc(text)
    params.text = GCHandle.ToIntPtr(textHandle)

    Dim values As Integer() = {10, 20, 30}
    Dim valuesHandle As GCHandle = GCHandle.Alloc(values)
    params.values = GCHandle.ToIntPtr(heightHandle)

    StartApp(params)

    textHandle.Free()
    valuesHandle.Free()

  End Sub

当我实现这个时，我得到DLL的错误查找入口点。我想在VB中使用C ++的结构，可以使用哪些可能的解决方案来避免这种情况？