String.TrimStart String.TrimStart String.TrimStart String.TrimStart Method

Definition

Überlädt

TrimStart() TrimStart() TrimStart() TrimStart()
TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[])

Entfernt alle nachgestellten Vorkommen der Zeichen im angegebenen Array aus dem aktuellen String-Objekt.Removes all leading occurrences of a set of characters specified in an array from the current String object.

TrimStart(Char) TrimStart(Char) TrimStart(Char) TrimStart(Char)

TrimStart() TrimStart() TrimStart() TrimStart()

public:
 System::String ^ TrimStart();
public string TrimStart ();
member this.TrimStart : unit -> string
Public Function TrimStart () As String

Gibt zurück

TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[]) TrimStart(Char[])

Entfernt alle nachgestellten Vorkommen der Zeichen im angegebenen Array aus dem aktuellen String-Objekt.Removes all leading occurrences of a set of characters specified in an array from the current String object.

public:
 System::String ^ TrimStart(... cli::array <char> ^ trimChars);
public string TrimStart (params char[] trimChars);
member this.TrimStart : char[] -> string
Public Function TrimStart (ParamArray trimChars As Char()) As String

Parameter

trimChars
Char[]

Ein Array mit den zu entfernenden Unicode-Zeichen oder null.An array of Unicode characters to remove, or null.

Gibt zurück

Die resultierende Zeichenfolge, nachdem alle im trimChars-Parameter übergebenen Zeichen am Anfang der aktuellen Zeichenfolge entfernt wurden.The string that remains after all occurrences of characters in the trimChars parameter are removed from the start of the current string. Wenn trimChars null oder ein leeres Array ist, werden stattdessen Leerzeichen entfernt.If trimChars is null or an empty array, white-space characters are removed instead.

Beispiele

Im folgenden Beispiel werden die grundlegenden Funktionen TrimStart der-Methode veranschaulicht:The following example demonstrates the basic functionality of the TrimStart method:

// TrimStart examples
string lineWithLeadingSpaces = "   Hello World!";
string lineWithLeadingSymbols = "$$$$Hello World!";
string lineWithLeadingUnderscores = "_____Hello World!";
string lineWithLeadingLetters = "xxxxHello World!";
string lineAfterTrimStart = string.Empty;

// Make it easy to print out and work with all of the examples
string[] lines = { lineWithLeadingSpaces, lineWithLeadingSymbols, lineWithLeadingUnderscores, lineWithLeadingLetters };

foreach (var line in lines)
{
    Console.WriteLine($"This line has leading characters: {line}");
}
// Output:
// This line has leading characters:    Hello World!
// This line has leading characters: $$$$Hello World!
// This line has leading characters: _____Hello World!
// This line has leading characters: xxxxHello World!

// A basic demonstration of TrimStart in action
lineAfterTrimStart = lineWithLeadingSpaces.TrimStart(' ');
Console.WriteLine($"This is the result after calling TrimStart: {lineAfterTrimStart}");
// This is the result after calling TrimStart: Hello World!   

// Since TrimStart accepts a character array of leading items to be removed as an argument,
// it's possible to do things like trim multiple pieces of data that each have different 
// leading characters,
foreach (var lineToEdit in lines)
{
    Console.WriteLine(lineToEdit.TrimStart(' ', '$', '_', 'x'));
}
// Result for each: Hello World!

// or handle pieces of data that have multiple kinds of leading characters 
var lineToBeTrimmed = "__###__ John Smith";
lineAfterTrimStart = lineToBeTrimmed.TrimStart('_', '#', ' ');
Console.WriteLine(lineAfterTrimStart);
// Result: John Smith
Public Sub Main()
   ' TrimStart Examples
   Dim lineWithLeadingSpaces as String = "   Hello World!"
Dim lineWithLeadingSymbols as String = "$$$$Hello World!"
   Dim lineWithLeadingUnderscores as String = "_____Hello World!"
   Dim lineWithLeadingLetters as String = "xxxxHello World!"
   Dim lineAfterTrimStart = String.Empty

   ' Make it easy to print out and work with all of the examples
   Dim lines As String() = { lineWithLeadingSpaces, line lineWithLeadingSymbols, lineWithLeadingUnderscores, lineWithLeadingLetters }

   For Each line As String in lines
     Console.WriteLine($"This line has leading characters: {line}")
   Next
   ' Output:
   ' This line has leading characters:    Hello World!
   ' This line has leading characters: $$$$Hello World!
   ' This line has leading characters: _____Hello World!
   ' This line has leading characters: xxxxHello World!

   Console.WriteLine($"This line has leading spaces: {lineWithLeadingSpaces}")
   ' This line has leading spaces:   Hello World!

   ' A basic demonstration of TrimStart in action
   lineAfterTrimStart = lineWithLeadingSpaces.TrimStart(" "c)
   Console.WriteLine($"This is the result after calling TrimStart: {lineAfterTrimStart}")
   ' This is the result after calling TrimStart: Hello World!

   ' Since TrimStart accepts a character array of leading items to be removed as an argument,
   ' it's possible to do things like trim multiple pieces of data that each have different 
   ' leading characters,
   For Each lineToEdit As String in lines
     Console.WriteLine(lineToEdit.TrimStart(" "c, "$"c, "_"c, "x"c ))
   Next
   ' Result for each: Hello World!

   ' or handle pieces of data that have multiple kinds of leading characters
   Dim lineToBeTrimmed as String = "__###__ John Smith"
   lineAfterTrimStart = lineToBeTrimmed.TrimStart("_"c , "#"c , " "c)
   Console.WriteLine(lineAfterTrimStart)
   ' Result: John Smith

 End Sub

Im folgenden Beispiel wird die TrimStart -Methode verwendet, um Leerzeichen und Kommentarzeichen aus Zeilen des Quellcodes zu kürzen.The following example uses the TrimStart method to trim white space and comment characters from lines of source code. Die StripComments TrimStart -Methode umschließt einen-Vorgang und übergibt ihm ein Zeichen Array mit einem Leerzeichen und dem Kommentarzeichen, das ein Apostroph (') in Visual Basic und ein Schrägstrich (/ C#) in ist.The StripComments method wraps a call to TrimStart and passes it a character array that contains a space and the comment character, which is an apostrophe ( ' ) in Visual Basic and a slash ( / ) in C#. Die TrimStart -Methode wird auch aufgerufen, um führende Leerzeichen zu entfernen, wenn ausgewertet wird, ob eine Zeichenfolge ein Kommentar ist.The TrimStart method is also called to remove leading white space when evaluating whether a string is a comment.

public static string[] StripComments(string[] lines)
{
    List<string> lineList = new List<string>();
    foreach (string line in lines)
    {
        if (line.TrimStart(' ').StartsWith("//"))
            lineList.Add(line.TrimStart(' ', '/'));
    }
    return lineList.ToArray();
}
Public Shared Function StripComments(lines() As String) As String()
   Dim lineList As New List(Of String)
   For Each line As String In lines
      If line.TrimStart(" "c).StartsWith("'") Then
         linelist.Add(line.TrimStart("'"c, " "c))
      End If
   Next
   Return lineList.ToArray()
End Function   

Im folgenden Beispiel wird ein Aufruf der StripComments-Methode veranschaulicht.The following example then illustrates a call to the StripComments method.

public static void Main()
{
    string[] lines = {"using System;",
                   "",
                   "public class HelloWorld",
                   "{",
                   "   public static void Main()",
                   "   {",
                   "      // This code displays a simple greeting",
                   "      // to the console.",
                   "      Console.WriteLine(\"Hello, World.\");",
                   "   }",
                   "}"};
    Console.WriteLine("Before call to StripComments:");
    foreach (string line in lines)
        Console.WriteLine("   {0}", line);

    string[] strippedLines = StripComments(lines);
    Console.WriteLine("After call to StripComments:");
    foreach (string line in strippedLines)
        Console.WriteLine("   {0}", line);
}
// This code produces the following output to the console:
//    Before call to StripComments:
//       using System;
//   
//       public class HelloWorld
//       {
//           public static void Main()
//           {
//               // This code displays a simple greeting
//               // to the console.
//               Console.WriteLine("Hello, World.");
//           }
//       }  
//    After call to StripComments:
//       This code displays a simple greeting
//       to the console.
Public Shared Sub Main()
   Dim lines() As String = {"Public Module HelloWorld", _
                            "   Public Sub Main()", _
                            "      ' This code displays a simple greeting", _
                            "      ' to the console.", _
                            "      Console.WriteLine(""Hello, World."")", _
                            "   End Sub", _
                            " End Module"}
   Console.WriteLine("Code before call to StripComments:")
   For Each line As String In lines
      Console.WriteLine("   {0}", line)                         
   Next                            
   
   Dim strippedLines() As String = StripComments(lines) 
   Console.WriteLine("Code after call to StripComments:")
   For Each line As String In strippedLines
      Console.WriteLine("   {0}", line)                         
   Next                            
End Sub
' This code produces the following output to the console:
'    Code before call to StripComments:
'       Public Module HelloWorld
'          Public Sub Main()
'             ' This code displays a simple greeting
'             ' to the console.
'             Console.WriteLine("Hello, World.")
'          End Sub
'       End Module
'    Code after call to StripComments:
'       This code displays a simple greeting
'       to the console.   

Hinweise

Die TrimStart -Methode entfernt alle führenden Zeichen aus der aktuellen Zeichenfolge, die trimChars im-Parameter enthalten sind.The TrimStart method removes from the current string all leading characters that are in the trimChars parameter. Der Trim-Vorgang wird beendet, wenn ein Zeichen, trimChars das nicht in ist, gefunden wird.The trim operation stops when a character that is not in trimChars is encountered. Wenn die aktuelle Zeichenfolge z. b. "123abc456xyz789" trimChars ist und die Ziffern von "1" bis "9" enthält TrimStart , gibt die Methode "abc456xyz789" zurück.For example, if the current string is "123abc456xyz789" and trimChars contains the digits from "1" through "9", the TrimStart method returns "abc456xyz789".

Hinweis

Wenn die TrimStart -Methode alle Zeichen aus der aktuellen Instanz entfernt, ändert diese Methode nicht den Wert der aktuellen Instanz.If the TrimStart method removes any characters from the current instance, this method does not modify the value of the current instance. Stattdessen wird eine neue Zeichenfolge zurückgegeben, in der alle in der aktuellen Instanz gefundenen führenden Leerzeichen entfernt werden.Instead, it returns a new string in which all leading white space characters found in the current instance are removed.

Hinweise für Aufrufer

In .NET Framework 3.5 SP1.NET Framework 3.5 SP1 und früheren Versionen wird eine interne Liste von leer Raum Zeichen verwaltet, die von dieser Methode nur trimChars dann null untersucht werden, wenn ist, oder ein leeres Array.The .NET Framework 3.5 SP1.NET Framework 3.5 SP1 and earlier versions maintains an internal list of white-space characters that this method trims if trimChars is null or an empty array. .NET Framework 4.NET Framework 4Beginnend mit IsWhiteSpace(Char) , wenn trimChars oder ein null leeres Array ist, schneidet die-Methode alle Unicode-Leerzeichen ab (d. h. Zeichen, die einen true Rückgabewert ergeben, wenn Sie an die-Methode übermittelt werden).Starting with the .NET Framework 4.NET Framework 4, if trimChars is null or an empty array, the method trims all Unicode white-space characters (that is, characters that produce a true return value when they are passed to the IsWhiteSpace(Char) method). Aufgrund dieser Änderung entfernt Trim() die-Methode in der-und der .NET Framework 3.5 SP1.NET Framework 3.5 SP1 früheren-Version zwei Zeichen, den Leerraum (u + 200B) und den NULL-Wert ohne Umbruch Zeichen (u + FEFF) Trim() , .NET Framework 4.NET Framework 4 dass die-Methode in und höheren Versionen nicht entfernen.Because of this change, the Trim() method in the .NET Framework 3.5 SP1.NET Framework 3.5 SP1 and earlier versions removes two characters, ZERO WIDTH SPACE (U+200B) and ZERO WIDTH NO-BREAK SPACE (U+FEFF), that the Trim() method in the .NET Framework 4.NET Framework 4 and later versions does not remove. Außerdem werden mit der Trim() .NET Framework 3.5 SP1.NET Framework 3.5 SP1 -Methode in und früheren Versionen nicht drei Unicode-leer Raum Zeichen beschnitten: Mongolischer vowel-Trennzeichen (u + 180E), schmaler, nicht Umbruch Bereich (u + 202F) und mittlerer mathematischer Raum (u + 205f).In addition, the Trim() method in the .NET Framework 3.5 SP1.NET Framework 3.5 SP1 and earlier versions does not trim three Unicode white-space characters: MONGOLIAN VOWEL SEPARATOR (U+180E), NARROW NO-BREAK SPACE (U+202F), and MEDIUM MATHEMATICAL SPACE (U+205F).

Siehe auch

TrimStart(Char) TrimStart(Char) TrimStart(Char) TrimStart(Char)

public:
 System::String ^ TrimStart(char trimChar);
public string TrimStart (char trimChar);
member this.TrimStart : char -> string
Public Function TrimStart (trimChar As Char) As String

Parameter

trimChar
Char Char Char Char

Gibt zurück

Gilt für: