当我正在调试时,当我运行一个编译的.exe时,我会看到不同的行为,例外被捕获或被抓住.我有两种形式(Form1和Form2). Form1上有一个按钮,它在Form2上实例化并调用ShowDialog. Form2有一个按钮,它有意地产生一个除零的错误.当我调试时,Form1中的catch块被击中.当我运行编译的.exe,它没有被打击,而是我收到一个消息框,指出“您的应用程序中发生了未处理的异常.如果您单击继续,应用程序将忽略此错误并尝试继续.点击退出,应用程序将立即关闭…尝试除以零“.我的问题是为什么在调试时和运行.exe时会有不同的行为？如果这是预期的行为,那么认为有必要在每一个事件处理程序中放置try / catch块？看起来有点疯狂杀了,不是吗？
这是Form1的代码.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender,EventArgs e)
{
try
{
Form2 f2 = new Form2();
f2.ShowDialog();
}
catch(Exception eX)
{
MessageBox.Show( eX.ToString()); //This line hit when debugging only
}
}
}
这是Form2的代码：
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private void button1_Click(object sender,EventArgs e)
{
int x = 0;
int y = 7 / x;
}
}
解决方法
我得到和你一样的行为.我不知道为什么会发生这种情况,但是假设从表单中的事件生成的异常将出现在ShowDialog()调用的堆栈上似乎是一个坏主意.做这两件事情会更好
>抓住并处理Form2中的事件处理程序中的异常,这样做是有意义的,当您可以对异常进行有意义的事情时.
>为整个应用程序添加一个未处理的异常处理程序(“Application_ThreadException”),以捕获任何未处理的异常.
更新：这是堆栈跟踪.调试版本：
System.DivideByZeroException: Attempted to divide by zero. at WindowsFormsApplication1.Form2.button1_Click(Object sender,EventArgs e) in ...\WindowsFormsApplication1\Form2.cs:line 27 at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) 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.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.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(Int32 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 System.Windows.Forms.Application.RunDialog(Form form) at System.Windows.Forms.Form.ShowDialog(IWin32Window owner) at System.Windows.Forms.Form.ShowDialog() at WindowsFormsApplication1.Form1.button1_Click(Object sender,EventArgs e) in ...\WindowsFormsApplication1\Form1.cs:line 45
发布：
System.DivideByZeroException: Attempted to divide by zero. at WindowsFormsApplication1.Form2.button1_Click(Object sender,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.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd,IntPtr lparam)
请注意,System.Windows.Forms.Form.ShowDialog()不是在释放模式下的堆栈跟踪,这就是为什么你的try {} catch {}什么都不做.另外值得注意的是,在调试的情况下,它使用的是NativeWindow.DebuggableCallback,大概是通过不打破堆栈来帮助调试,而在Release模式下使用NativeWindow.Callback.
