How to: Perform String Manipulations by Using Basic String Operations

The following example uses some of the methods discussed in the Basic String Operations topics to construct a class that performs string manipulations in a manner that might be found in a real-world application. The MailToData class stores the name and address of an individual in separate properties and provides a way to combine the City, State, and Zip fields into a single string for display to the user. Furthermore, the class allows the user to enter the city, state, and ZIP Code information as a single string; the application automatically parses the single string and enters the proper information into the corresponding property.

For simplicity, this example uses a console application with a command-line interface.

Example

Class MainClass
   Public Shared Sub Main()
      Dim MyData As New MailToData()

      Console.Write("Enter Your Name: ")
      MyData.Name = Console.ReadLine()
      Console.Write("Enter Your Address: ")
      MyData.Address = Console.ReadLine()
      Console.Write("Enter Your City, State, and ZIP Code separated by spaces: ")
      MyData.CityStateZip = Console.ReadLine()
      Console.WriteLine()

      If MyData.Validated Then
         Console.WriteLine("Name: {0}", MyData.Name)
         Console.WriteLine("Address: {0}", MyData.Address)
         Console.WriteLine("City: {0}", MyData.City)
         Console.WriteLine("State: {0}", MyData.State)
         Console.WriteLine("ZIP Code: {0}", MyData.Zip)

         Console.WriteLine("The following address will be used:")
         Console.WriteLine(MyData.Address)
         Console.WriteLine(MyData.CityStateZip)
      End If 
   End Sub 
End Class 

Public Class MailToData
   Private strName As String = "" 
   Private strAddress As String = "" 
   Private strCityStateZip As String = "" 
   Private strCity As String = "" 
   Private strState As String = "" 
   Private strZip As String = "" 
   Private parseSucceeded As Boolean = False 

   Public Property Name() As String 
      Get 
         Return strName
      End Get 
      Set
         strName = value
      End Set 
   End Property  

   Public Property Address() As String 
      Get 
         Return strAddress
      End Get 
      Set
         strAddress = value
      End Set 
   End Property  

   Public Property CityStateZip() As String 
      Get 
         Return String.Format("{0}, {1} {2}", strCity, strState, strZip)
      End Get 
      Set
         strCityStateZip = value.Trim()
         ParseCityStateZip()
      End Set 
   End Property 

   Public Property City() As String 
      Get 
         Return strCity
      End Get 
      Set
         strCity = value
      End Set 
   End Property  

   Public Property State() As String 
      Get 
         Return strState
      End Get 
      Set
         strState = value
      End Set 
   End Property  

   Public Property Zip() As String 
      Get 
         Return strZip
      End Get 
      Set
         strZip = value
      End Set 
   End Property 

   Public ReadOnly Property Validated As Boolean 
      Get 
         Return parseSucceeded 
      End Get 
   End Property  

   Private Sub ParseCityStateZip()
      Dim msg As String = Nothing 
      Const msgEnd As String = vbCrLf + _ 
                               "You must enter spaces between city, state, and zip code." + _
                               vbCrLf

      ' Throw a FormatException if the user did not enter the necessary spaces 
      ' between elements.  
      Try 
         ' City may consist of multiple words, so we'll have to parse the  
         ' string from right to left starting with the zip code. 
         Dim zipIndex As Integer = strCityStateZip.LastIndexOf(" ")
         If zipIndex = -1 Then 
            msg = vbCrLf + "Cannot identify a zip code." + msgEnd
            Throw New FormatException(msg)
         End If
         strZip = strCityStateZip.Substring(zipIndex + 1)        

         Dim stateIndex As Integer = strCityStateZip.LastIndexOf(" ", zipIndex - 1)
         If stateIndex = -1 Then  
            msg = vbCrLf + "Cannot identify a state." + msgEnd
            Throw New FormatException(msg)
         End If
         strState = strCityStateZip.Substring(stateIndex + 1, zipIndex - stateIndex - 1)        
         strState = strState.ToUpper()

         strCity = strCityStateZip.Substring(0, stateIndex)
         If strCity.Length = 0 Then
            msg = vbCrLf + "Cannot identify a city." + msgEnd
            Throw New FormatException(msg)
         End If
         parseSucceeded = True 
      Catch ex As FormatException
         Console.WriteLine(ex.Message)  
      End Try 
   End Sub 
End Class

using System;

class MainClass
{
   static void Main()
   {
      MailToData MyData = new MailToData();

      Console.Write("Enter Your Name: ");
      MyData.Name = Console.ReadLine();
      Console.Write("Enter Your Address: ");
      MyData.Address = Console.ReadLine();
      Console.Write("Enter Your City, State, and ZIP Code separated by spaces: ");
      MyData.CityStateZip = Console.ReadLine();
      Console.WriteLine();

      if (MyData.Validated) {
         Console.WriteLine("Name: {0}", MyData.Name);
         Console.WriteLine("Address: {0}", MyData.Address);
         Console.WriteLine("City: {0}", MyData.City);
         Console.WriteLine("State: {0}", MyData.State);
         Console.WriteLine("Zip: {0}", MyData.Zip);

         Console.WriteLine("\nThe following address will be used:");
         Console.WriteLine(MyData.Address);
         Console.WriteLine(MyData.CityStateZip);
      }
   }
}

public class MailToData
{
   string name = "";
   string address = ""; 
   string citystatezip = "";
   string city = ""; 
   string state = ""; 
   string zip = "";
   bool parseSucceeded = false;

   public string Name
   {
      get{return name;}
      set{name = value;}
   }

   public string Address
   {
      get{return address;}
      set{address = value;}
   }

   public string CityStateZip
   {
      get { 
         return String.Format("{0}, {1} {2}", city, state, zip); 
      }
      set {
         citystatezip = value.Trim();
         ParseCityStateZip();
      }
   }

   public string City
   {
      get{return city;}
      set{city = value;}
   }

   public string State
   {
      get{return state;}
      set{state = value;}
   }

   public string Zip
   {
      get{return zip;}
      set{zip = value;}
   }

   public bool Validated
   {
      get { return parseSucceeded; }
   }

   private void ParseCityStateZip()
   {  
      string msg = "";
      const string msgEnd = "\nYou must enter spaces between city, state, and zip code.\n";

      // Throw a FormatException if the user did not enter the necessary spaces 
      // between elements.  
      try
      {
         // City may consist of multiple words, so we'll have to parse the  
         // string from right to left starting with the zip code. 
         int zipIndex = citystatezip.LastIndexOf(" ");
         if (zipIndex == -1) { 
            msg = "\nCannot identify a zip code." + msgEnd;
            throw new FormatException(msg);
         }
         zip = citystatezip.Substring(zipIndex + 1);        

         int stateIndex = citystatezip.LastIndexOf(" ", zipIndex - 1);
         if (stateIndex == -1) {  
            msg = "\nCannot identify a state." + msgEnd;
            throw new FormatException(msg);
         }
         state = citystatezip.Substring(stateIndex + 1, zipIndex - stateIndex - 1);        
         state = state.ToUpper();

         city = citystatezip.Substring(0, stateIndex);
         if (city.Length == 0) {
            msg = "\nCannot identify a city." + msgEnd;
            throw new FormatException(msg);
         }
         parseSucceeded = true;
      }
      catch (FormatException ex)
      {
         Console.WriteLine(ex.Message);
      } 
   }

   private string ReturnCityStateZip()
    {
        // Make state uppercase.
        state = state.ToUpper();

        // Put the value of city, state, and zip together in the proper manner. 
        string MyCityStateZip = String.Concat(city, ", ", state, " ", zip);

        return MyCityStateZip;
    }
}

See Also

Other Resources

Basic String Operations

Change History

Date	History	Reason
September 2011	Modified the example to handle multi-word cities.	Customer feedback.