C#实现Excel中文本框单元格之间修改公式的一个异常


//文本框给单元格修改值
        private void txt_formula_TextChanged(object sender, EventArgs e)
        {
            object newValue = new object();
            newValue = ((TextBox)sender).Text;
            this.axSpreadsheet.Selection.Cells.set_Value(XlRangeValueType.xlRangeValueDefault,newValue);
        }
单元格自己修改没问题，一到文本框输入符号就异常，高手帮忙解决未处理 System.Runtime.InteropServices.COMException
  Message="异常来自 HRESULT:0xE004002F"
  Source="Microsoft.Office.Interop.Owc11"
  ErrorCode=-536608721
  StackTrace:
       在 Microsoft.Office.Interop.Owc11.RangeClass.set_Value(Object RangeValueDataType, Object Value)
       在 witjointStatement.frmMain.txt_formula_TextChanged(Object sender, EventArgs e) 位置 E:\Objects\witjointStatement\witjointStatement\frmMain.cs:行号 531
       在 System.Windows.Forms.Control.OnTextChanged(EventArgs e)
       在 System.Windows.Forms.TextBoxBase.OnTextChanged(EventArgs e)
       在 System.Windows.Forms.TextBoxBase.WmReflectCommand(Message& m)
       在 System.Windows.Forms.TextBoxBase.WndProc(Message& m)
       在 System.Windows.Forms.TextBox.WndProc(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       在 System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       在 System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       在 System.Windows.Forms.Control.SendMessage(Int32 msg, IntPtr wparam, IntPtr lparam)
       在 System.Windows.Forms.Control.ReflectMessageInternal(IntPtr hWnd, Message& m)
       在 System.Windows.Forms.Control.WmCommand(Message& m)
       在 System.Windows.Forms.Control.WndProc(Message& m)
       在 System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       在 System.Windows.Forms.ContainerControl.WndProc(Message& m)
       在 System.Windows.Forms.Form.WndProc(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       在 System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       在 System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       在 System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
       在 System.Windows.Forms.Control.DefWndProc(Message& m)
       在 System.Windows.Forms.Control.WmKeyChar(Message& m)
       在 System.Windows.Forms.Control.WndProc(Message& m)
       在 System.Windows.Forms.TextBoxBase.WndProc(Message& m)
       在 System.Windows.Forms.TextBox.WndProc(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       在 System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       在 System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       在 System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
       在 System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       在 System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       在 System.Windows.Forms.Application.Run(Form mainForm)
       在 witjointStatement.Program.Main() 位置 E:\Objects\witjointStatement\witjointStatement\Program.cs:行号 17
       在 System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       在 System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       在 Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       在 System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       在 System.Threading.ThreadHelper.ThreadStart()