次の c# コードを使用して 250000 ビット/秒のボー レートで COM5 ポートにアクセスしようとしていますが、以下の行で例外メッセージが表示されますselectedbaudrate = Convert.ToInt32 (cmbBaudRate.SelectedItem.ToString());。pronterface.pyプログラムを使用すると、この速度でデバイスにアクセスできます。書いたときに変数に乗る0のはなぜですか?selectedbaudrate250000
private void buttonOpenPort_Click(object sender, EventArgs e)
{
string selectedportname;
int selectedbaudrate;
selectedportname = combportnumber.SelectedItem.ToString();
selectedbaudrate = Convert.ToInt32 (cmbBaudRate.SelectedItem.ToString());
port = new SerialPort(selectedportname, selectedbaudrate, Parity.None, 8, StopBits.One);
port.DtrEnable = true;
port.Open();
port.DataReceived += serialPort1_DataReceived;
}
例外：
System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=PC Host
StackTrace:
at WindowsFormsApplication1.Form1.buttonOpenPort_Click(Object sender, EventArgs e) in D:\Catia V5 Projects\HF08 Hexapod\Version 05\Host PC Software\PC Host 13\PC Host\Form1.cs:line 106
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at WindowsFormsApplication1.Program.Main() in D:\Catia V5 Projects\HF08 Hexapod\Version 05\Host PC Software\PC Host 13\PC Host\Program.cs:line 18
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException: