如何在代码中处理外部异常

Question

I am trying to capture image on the count of a timer and save it automatically for which I have tried a code But an External Exception is been thrown when I run this code.And if i try to catch the exception the code runs but it doesn't save the captured image neither in the mentioned path nor anywhere else. Here picCap is the name of my pictureBox

My code is,

    WebCam webcam;
    int duration = 0;

    private void timer1_Tick(object sender, EventArgs e)
    {
        duration++;
        textBox1.Text = duration.ToString();
        bool ischecked = radioButton2.Checked;

            if (duration <= 3)
            {
                radioButton2.Checked = true;
                if (radioButton2.Checked == true)
                {


                    picCap.Image.Save(@"C:\Users\Administrator\Desktop", ImageFormat.Jpeg);
                   //External Exception not handled

                }
                else
                {
                    webcam.Stop();
                    timer1.Stop();
                }

            }
            else
            {
                radioButton2.Checked = false;
                //     radioButton3.Visible = false;
                radioButton3.Checked = true;

            }


    }
    //start
    private void button1_Click(object sender, EventArgs e)
    {
        timer1.Enabled = true;
        timer1.Start();
        webcam.Start();
    }
    //stop
    private void button2_Click(object sender, EventArgs e)
    {
        timer1.Stop();
        webcam.Stop();
    }

    private void mainWinForm_Load(object sender, EventArgs e)
    {
        webcam = new WebCam();
        webcam.InitializeWebCam(ref picCap);
    }

Extra details about the exception

System.Runtime.InteropServices.ExternalException was unhandled by user code
HResult=-2147467259
Message=A generic error occurred in GDI+.
Source=System.Drawing
ErrorCode=-2147467259
 StackTrace:
   at System.Drawing.Image.Save(String filename, ImageCodecInfo encoder, EncoderParameters encoderParams)
   at System.Drawing.Image.Save(String filename, ImageFormat format)
   at WindowsFormsApplication3.mainWinForm.timer1_Tick(Object sender, EventArgs e) in C:\Users\Administrator\documents\visual studio 2010\Projects\WindowsFormsApplication3\WindowsFormsApplication3\Form1.cs:line 37
   at System.Windows.Forms.Timer.OnTick(EventArgs e)
   at System.Windows.Forms.Timer.TimerNativeWindow.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 System.Windows.Forms.Application.DoEvents()
   at WebCam_Capture.WebCamCapture.timer1_Tick(Object sender, EventArgs e)
 InnerException: 

Answer 1

The exception indicates that the method requires a filename and not a folder path:

System.Drawing.Image.Save(String filename, ImageCodecInfo encoder, EncoderParameters encoderParams)

It's likely failing because it can't save the file without the filename, so try adding one like the following example:

picCap.Image.Save(@"C:\Users\Administrator\Desktop\MyFilename.jpeg", ImageFormat.Jpeg);