function Berechne2(A: integer; B: integer): integer; stdcall;
begin
  result := a+b;
end;
 
function GetStr2: PChar; stdcall;
begin
  result := 'Dies ist meine schöne DLL';
end;

Imports System.Runtime.InteropServices
...
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim a, b As Integer
 
        a = Convert.ToInt16(TextBox1.Text())
        b = Convert.ToInt16(TextBox2.Text())
 
        Button1.Text() = Convert.ToString(Berechne2(a, b))
        Label1.Text() = Convert.ToString(GetStr2())
 
    End Sub
...
    <DllImport("fuerasp.dll", EntryPoint:="Berechne2", SetLastError:=True, _
    CharSet:=CharSet.Unicode, ExactSpelling:=True, _
    CallingConvention:=CallingConvention.StdCall)> _
    Public Shared Function Berechne2(ByVal A As Integer, ByVal B As Integer) As _
    Integer
 
    End Function
 
    <DllImport("fuerasp.dll", EntryPoint:="GetStr2", SetLastError:=True, _
    ExactSpelling:=True, _
    CallingConvention:=CallingConvention.StdCall)> _
    Public Shared Function GetStr2() As System.Text.StringBuilder
    End Function

Zitat:

System.ArgumentOutOfRangeException: Die maximale Kapazität wurde überschritten. Parametername: capacity