Windows窗體加載然後退出

Question

我正在爲超市創建結帳系統。它由一個結帳，服務器和MIS程序組成，在它們之間運行WCF服務。我遇到的問題是checkout程序是一個windows窗體，它在application_load方法中做了一些必要的事情，然後就退出了。

下面的代碼：

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Windows.Forms; 
using CheckoutLibrary; 
using Checkout.ServerLibraryService; 
using Checkout.MarketService; 

namespace Checkout 
{ 
    public partial class theForm : Form 
    { 
     private static int checkoutID = 3; 
     private Product[] allProducts; 

     public theForm() 
     { 
      InitializeComponent(); 
     } 

     private void theForm_Load(object sender, EventArgs e) 
     { 
      // First cache all products 
      SupermarketServiceSoapClient marketService = new SupermarketServiceSoapClient(); 
      allProducts = marketService.GetAllProducts(); 
      // Load the service provided by the server 
      ServiceClient serverService = new ServiceClient(); 
      // Load the event handlers for the bar code scanner 
      BarcodeScanner scanner = new BarcodeScanner(); 
      scanner.ItemScanned += new BarcodeScanner.ItemScannedHandler(scanner_ItemScanned); 
      scanner.AllItemsScanned += new BarcodeScanner.AllItemsScannedHandler(scanner_AllItemsScanned); 
      scanner.Start(checkoutID); 
     } 

     void scanner_AllItemsScanned(EventArgs args) 
     { 
      throw new NotImplementedException(); 
     } 

     void scanner_ItemScanned(ScanEventArgs args) 
     { 
      itemTextBox.Text = "Scanned " + GetItemName(args.Barcode); 
     } 

     private void scanItemButton_Click(object sender, EventArgs e) 
     { 
      scanner_ItemScanned(new ScanEventArgs(GetRandBarcode())); 
     } 

     // A barcode -> product name look up method 
     public string GetItemName(int barcode) 
     { 
      return allProducts[barcode].Description + " @ " + allProducts[barcode].Price; 
     } 

     // Method to grab a random barcode for simulation 
     private int GetRandBarcode() 
     { 
      Random rand = new Random(); 
      return rand.Next(0,500); 
     } 
    } 
} 

而且Program.cs的：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Windows.Forms; 

namespace Checkout 
{ 
    static class Program 
    { 
     /// <summary> 
     /// The main entry point for the application. 
     /// </summary> 
     [STAThread] 
     static void Main() 
     { 
      Application.EnableVisualStyles(); 
      Application.SetCompatibleTextRenderingDefault(false); 
      Application.Run(new theForm()); 
     } 
    } 
} 

感謝任何見解。

Answer 1

在WinForms中，如果您的form_load引發異常，它將退出而不顯示任何內容。討厭，但我猜這就是問題所在。

您可以嘗試try/catch，或者您可以點擊CTRL+ALT+E並檢查Thrown Column的Common Language Runtime Exceptions以查看錯誤。

更新：根據意見

，這裏是一個樣本的方式在另一個線程中執行的東西。

ThreadStart ts = new ThreadStart(() => { 
    try { 
     scanner.Start(checkoutID); 
    } catch { 
     // Log error 
    } 
}); 
Thread t = new Thread(ts); 
t.Start();