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CharEnumerator.MoveNext Método

Definición

Incrementa el índice interno del objeto CharEnumerator actual hasta el siguiente carácter de la cadena enumerada.

public:
 virtual bool MoveNext();
public bool MoveNext ();
abstract member MoveNext : unit -> bool
override this.MoveNext : unit -> bool
Public Function MoveNext () As Boolean

Devoluciones

Es true si el índice se incrementa correctamente y dentro de la cadena enumerada; en caso contrario, es false.

Implementaciones

Ejemplos

En el ejemplo siguiente se usa la CharEnumerator clase para enumerar los caracteres individuales de una cadena. Crea una instancia de un CharEnumerator objeto llamando al String.GetEnumerator método , se mueve de un carácter a otro llamando al MoveNext método y muestra el carácter actual recuperando el valor de la Current propiedad .

String ^ title = "A Tale of Two Cities";
CharEnumerator ^ chEnum = title->GetEnumerator();
int ctr = 1;
String ^ outputLine1 = nullptr;
String ^ outputLine2 = nullptr;
String ^ outputLine3 = nullptr; 

while (chEnum->MoveNext())
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += chEnum->Current + " ";
   ctr++;
}

Console::WriteLine("The length of the string is {0} characters:", 
                  title->Length);
Console::WriteLine(outputLine1);
Console::WriteLine(outputLine2);    
Console::WriteLine(outputLine3);
// The example displays the following output to the console:      
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
string title = "A Tale of Two Cities";
CharEnumerator chEnum = title.GetEnumerator();
int ctr = 1;
string outputLine1 = null;
string outputLine2 = null;
string outputLine3 = null;

while (chEnum.MoveNext())
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += chEnum.Current + " ";
   ctr++;
}

Console.WriteLine("The length of the string is {0} characters:",
                  title.Length);
Console.WriteLine(outputLine1);
Console.WriteLine(outputLine2);
Console.WriteLine(outputLine3);
// The example displays the following output to the console:
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
let title = "A Tale of Two Cities"
let chEnum = title.GetEnumerator()

printfn $"The length of the string is {title.Length} characters:"

let mutable outputLine1 = ""
let mutable outputLine2 = ""
let mutable outputLine3 = ""
let mutable i = 1

while chEnum.MoveNext() do
    outputLine1 <- outputLine1 + if i < 10 || i % 10 <> 0 then "  " else $"{i / 10} "
    outputLine2 <- outputLine2 + $"{i % 10} ";
    outputLine3 <- outputLine3 + $"{chEnum.Current} "
    i <- i + 1

printfn "%s" outputLine1
printfn "%s" outputLine2
printfn "%s" outputLine3

// The example displays the following output to the console:
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
Dim title As String = "A Tale of Two Cities"
Dim chEnum As CharEnumerator = title.GetEnumerator()
Dim ctr As Integer = 1
Dim outputLine1, outputLine2, outputLine3 As String 

Do While chEnum.MoveNext()
   outputLine1 += CStr(iif(ctr < 10 Or ctr Mod 10 <> 0, "  ", CStr(ctr \ 10) + " ")) 
   outputLine2 += (ctr Mod 10)& " "
   outputLine3 += chEnum.Current & " "
   ctr += 1
Loop

Console.WriteLine("The length of the string is {0} characters:", _
                  title.Length)
Console.WriteLine(outputLine1)
Console.WriteLine(outputLine2)    
Console.WriteLine(outputLine3)
' The example displays the following output to the console:      
'       The length of the string is 20 characters:
'                         1                   2
'       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
'       A   T a l e   o f   T w o   C i t i e s

Sin embargo, tenga en cuenta que la misma operación se puede realizar de forma algo más intuitiva mediante foreach (en C#) o For Each (en Visual Basic), como se muestra en el ejemplo siguiente.

String ^ title = "A Tale of Two Cities";
int ctr = 1;
String ^ outputLine1 = nullptr;
String ^ outputLine2 = nullptr;
String ^ outputLine3 = nullptr; 

for each (wchar_t ch in title)
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += ch + " ";
   ctr++;
}

Console::WriteLine("The length of the string is {0} characters:", 
                  title->Length);
Console::WriteLine(outputLine1);
Console::WriteLine(outputLine2);    
Console::WriteLine(outputLine3);
// The example displays the following output to the console:      
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
string title = "A Tale of Two Cities";
int ctr = 1;
string outputLine1 = null;
string outputLine2 = null;
string outputLine3 = null;

foreach (char ch in title)
{
   outputLine1 += ctr < 10 || ctr % 10 != 0 ? "  " : (ctr / 10) + " ";
   outputLine2 += (ctr % 10) + " ";
   outputLine3 += ch + " ";
   ctr++;
}

Console.WriteLine("The length of the string is {0} characters:",
                  title.Length);
Console.WriteLine(outputLine1);
Console.WriteLine(outputLine2);
Console.WriteLine(outputLine3);
// The example displays the following output to the console:
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
let title = "A Tale of Two Cities"
let chEnum = title.GetEnumerator()

printfn $"The length of the string is {title.Length} characters:"

let mutable outputLine1 = ""
let mutable outputLine2 = ""
let mutable outputLine3 = ""
let mutable i = 1

for ch in title do
    outputLine1 <- outputLine1 + if i < 10 || i % 10 <> 0 then "  " else $"{i / 10} "
    outputLine2 <- outputLine2 + $"{i % 10} ";
    outputLine3 <- outputLine3 + $"{ch} "
    i <- i + 1

printfn "%s" outputLine1
printfn "%s" outputLine2
printfn "%s" outputLine3

// The example displays the following output to the console:
//       The length of the string is 20 characters:
//                         1                   2
//       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
//       A   T a l e   o f   T w o   C i t i e s
Dim title As String = "A Tale of Two Cities"
Dim ctr As Integer = 1
Dim outputLine1, outputLine2, outputLine3 As String 

For Each ch As Char In title
   outputLine1 += CStr(iif(ctr < 10 Or ctr Mod 10 <> 0, "  ", CStr(ctr \ 10) + " ")) 
   outputLine2 += (ctr Mod 10)& " "
   outputLine3 += ch & " "
   ctr += 1
Next

Console.WriteLine("The length of the string is {0} characters:", _
                  title.Length)
Console.WriteLine(outputLine1)
Console.WriteLine(outputLine2)    
Console.WriteLine(outputLine3)
' The example displays the following output to the console:      
'       The length of the string is 20 characters:
'                         1                   2
'       1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
'       A   T a l e   o f   T w o   C i t i e s

Comentarios

La CharEnumerator clase mantiene un índice interno en la cadena enumerada y el MoveNext método incrementa el índice en uno. Llame MoveNext a después de llamar GetEnumerator a o Reset para incrementar la posición del carácter actual al primer carácter de la cadena enumerada. Compruebe que el valor devuelto es true determinar que la posición del carácter actual es válida.

Si el índice ya está más allá del último carácter de la cadena enumerada, el índice no se cambia y false se devuelve.

Observe que si la cadena enumerada está vacía (""), el estado de CharEnumerator siempre no es válido. Esto se debe a que el índice interno de CharEnumerator es inicialmente antes del primer carácter de la cadena enumerada y, por tanto, no es válido. MoveNext establece lógicamente el índice después del último carácter (inexistente) de la cadena enumerada que tampoco es válida.

Se aplica a