ch10_05.cs

来自「《c#技术内幕代码》」· CS 代码 · 共 137 行

using System; 
using System.Data; 
using System.Data.ADO; 

public class CH10_4
{ 
   public static int GetMenuSelection()
   {
      Console.WriteLine("Please select how you want to find a record:");
      Console.WriteLine("{0} Exit");
      Console.WriteLine("(1) By Name");
      Console.WriteLine("(2) By City" );
      Console.WriteLine("(3) By State");
      int selection = -1;
      do
      {
         Console.WriteLine("\nEnter your Selection: ");
	 string s = Console.ReadLine();
	 try
	 {
  	    selection = s.ToInt16();
	 }
	 catch
	 {
	    selection = -1;
	 }
      } while ( selection < 0 || selection > 3 );
      return selection;
      
   }
   public static void Main () 
   { 
       // Define the connection string
       string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=CH10.MDB"; 
       
       // Find out what they want to delete.
       Boolean done = false;
       
       while ( !done )
       {
           string value = "";
	   string strSelect = "";
	   
           switch ( GetMenuSelection() )
	   {
	      case 0:
	         done = true;
		 break;
	      case 1: // Name
	         Console.WriteLine("Enter name to find: ");
		 value = Console.ReadLine();
		 strSelect = "SELECT * from Contact where Name Like \"";
		 break;
	      case 2: // City
	         Console.WriteLine("Enter city to find: ");
		 value = Console.ReadLine();
		 strSelect = "SELECT * from Contact where City Like \"";
		 break;
	      case 3: // State
	         Console.WriteLine("Enter state to find: ");
		 value = Console.ReadLine();
		 strSelect = "SELECT * from Contact where State Like \"";
		 break;
	   }
	   
	   if ( done )
	      break;
	   strSelect += value;
	   strSelect += "\";";
  
           // Create the connection object, using our connection string
           ADOConnection myConn = new ADOConnection(strConn); 

           // Create the command object from our selection criteria string       
           ADOCommand myCmd = new ADOCommand( strSelect, myConn ); 

           // Try to execute the command       
           ADODataReader outData = null; 
           try 
           { 
               // This will do the connection to the database
               myConn.Open(); 
	    
               // This will run our query and put the result in outData
               myCmd.Execute( out outData ); 
	       
               // See if we got something back
               if ( outData != null ) 
               { 
                    while (outData.Read() ) 
                    { 
		        Console.WriteLine( "ID: {0}", outData["ID"]);
                        Console.WriteLine( "Name: {0}", outData["Name"]); 
                        Console.WriteLine( "Address: {0}", outData["Address"]); 
                        Console.WriteLine( "City: {0}", outData["City"]); 
                        Console.WriteLine( "State: {0}", outData["State"]); 
                        Console.WriteLine( "Zip Code: {0}", outData["ZipCode"]); 
                        Console.WriteLine( "Age: {0}", outData["Age"]); 
			
                        Console.Write("\nDo you wish to delete this record (y/n):");
			string resp = Console.ReadLine();
			if ( resp == "y" || resp == "Y" )
			{
			   
			   int id = (int)outData["ID"];
			   outData.Close();
			   
                           strSelect = "DELETE from Contact where ID = ";
                           strSelect += id;
                           strSelect += ";";
       
                           ADOCommand cmd = new ADOCommand( strSelect, myConn ); 
                           try
                           {
			        outData = null;
                                cmd.Execute( out outData ); 
                           }
                           catch ( Exception e )
                           {
                                Console.WriteLine("Exception in delete {0}", e );
                           }
			   break;
			}
                    } 
               } 

          
          } 
          catch ( Exception e )
          {
             Console.WriteLine("Exception {0}", e );
          }
       }
    }
}