String.Contains 方法

來源:

String.Searching.cs

來源:

String.Searching.cs

來源:

String.Searching.cs

public:
 bool Contains(System::String ^ value, StringComparison comparisonType);

public bool Contains (string value, StringComparison comparisonType);

member this.Contains : string * StringComparison -> bool

Public Function Contains (value As String, comparisonType As StringComparison) As Boolean

參數

傳回

如果 true 參數出現在這個字串內，或是 value 為空字串 ("")，則為 value，否則為 false。

來源:

String.Searching.cs

來源:

String.Searching.cs

來源:

String.Searching.cs

public:
 bool Contains(char value, StringComparison comparisonType);

public bool Contains (char value, StringComparison comparisonType);

member this.Contains : char * StringComparison -> bool

Public Function Contains (value As Char, comparisonType As StringComparison) As Boolean

參數

傳回

如果 value 參數出現在此字串內，則為 true；否則為 false。

來源:

String.Searching.cs

來源:

String.Searching.cs

來源:

String.Searching.cs

public:
 bool Contains(System::String ^ value);

public bool Contains (string value);

member this.Contains : string -> bool

Public Function Contains (value As String) As Boolean

參數

傳回

如果 true 參數出現在這個字串內，或是 value 為空字串 ("")，則為 value，否則為 false。

例外狀況

範例

下列範例會判斷字串 「fox」 是否為熟悉引號的子字串。 如果在字串中找到 「fox」 ，它也會顯示其起始位置。

using namespace System;

int main()
{
   String^ s1 = "The quick brown fox jumps over the lazy dog";
   String^ s2 = "fox";
   bool b = s1->Contains( s2 );
   Console::WriteLine( "Is the string, s2, in the string, s1?: {0}", b );
   if (b) {
      int index = s1->IndexOf(s2);
      if (index >= 0)
         Console::WriteLine("'{0} begins at character position {1}",
                            s2, index + 1);
   }
}
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17

string s1 = "The quick brown fox jumps over the lazy dog";
string s2 = "fox";
bool b = s1.Contains(s2);
Console.WriteLine("'{0}' is in the string '{1}': {2}",
                s2, s1, b);
if (b) {
    int index = s1.IndexOf(s2);
    if (index >= 0)
        Console.WriteLine("'{0} begins at character position {1}",
                      s2, index + 1);
}
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17

let s1 = "The quick brown fox jumps over the lazy dog"
let s2 = "fox"
let b = s1.Contains s2
printfn $"'{s2}' is in the string '{s1}': {b}"
if b then
    let index = s1.IndexOf s2
    if index >= 0 then
        printfn $"'{s2} begins at character position {index + 1}"
// This example displays the following output:
//    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
//    'fox begins at character position 17

Class Example
   Public Shared Sub Main()
      Dim s1 As String = "The quick brown fox jumps over the lazy dog"
      Dim s2 As String = "fox"
      Dim b As Boolean = s1.Contains(s2)
      Console.WriteLine("'{0}' is in the string '{1}': {2}",
                        s2, s1, b)
      If b Then
          Dim index As Integer = s1.IndexOf(s2)
          If index >= 0 Then
             Console.WriteLine("'{0} begins at character position {1}",
                               s2, index + 1)
          End If
       End If
   End Sub
End Class
'
' This example displays the following output:
'    'fox' is in the string 'The quick brown fox jumps over the lazy dog': True
'    'fox begins at character position 17

備註

這個方法會執行序數 (區分大小寫且不區分文化特性) 比較。 搜尋會從此字串的第一個字元位置開始，並繼續進行最後一個字元位置。

若要執行區分文化特性或不區分大小寫的比較：

• 在 .NET Core 2.1 和更新版本上：改為呼叫多 Contains(String, StringComparison) 載。

• 在 .NET Framework：Create 自定義方法。 下列範例說明其中一種方法。 它會定義 String 包含參數的擴充方法， StringComparison 並指出字串在使用指定的字串比較形式時，是否包含子字串。

using System;

public static class StringExtensions
{
   public static bool Contains(this String str, String substring, 
                               StringComparison comp)
   {                            
        if (substring == null)
            throw new ArgumentNullException("substring", 
                                         "substring cannot be null.");
        else if (! Enum.IsDefined(typeof(StringComparison), comp))
            throw new ArgumentException("comp is not a member of StringComparison",
                                     "comp");

        return str.IndexOf(substring, comp) >= 0;                      
   }
}

open System
open System.Runtime.CompilerServices

[<Extension>]
type StringExtensions =
    [<Extension>]
    static member Contains(str: string, substring, comp: StringComparison) =
        if substring = null then
            invalidArg "substring" "substring cannot be null"
        if Enum.IsDefined(typeof<StringComparison>, comp) |> not then
            invalidArg "comp" "comp is not a member of StringComparison"
        str.IndexOf(substring, comp) >= 0

String s = "This is a string.";
String sub1 = "this";
Console.WriteLine("Does '{0}' contain '{1}'?", s, sub1);
StringComparison comp = StringComparison.Ordinal;
Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp));

comp = StringComparison.OrdinalIgnoreCase;
Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp));

// The example displays the following output:
//       Does 'This is a string.' contain 'this'?
//          Ordinal: False
//          OrdinalIgnoreCase: True

let s = "This is a string."
let sub1 = "this"
printfn $"Does '{s}' contain '{sub1}'?"
let comp = StringComparison.Ordinal
printfn $"   {comp:G}: {s.Contains(sub1, comp)}"

let comp2 = StringComparison.OrdinalIgnoreCase
printfn $"   {comp2:G}: {s.Contains(sub1, comp2)}"

// The example displays the following output:
//       Does 'This is a string.' contain 'this'?
//          Ordinal: False
//          OrdinalIgnoreCase: True

Imports System.Runtime.CompilerServices

Module StringExtensions
   <Extension()>
   Public Function Contains(str As String, substring As String, 
                            comp As StringComparison) As Boolean
      If substring Is Nothing Then
         Throw New ArgumentNullException("substring", 
                                         "substring cannot be null.")
      Else If Not [Enum].IsDefined(GetType(StringComparison), comp)
         Throw New ArgumentException("comp is not a member of StringComparison",
                                     "comp")
      End If                               
      Return str.IndexOf(substring, comp) >= 0                      
   End Function
End Module

Public Module Example
   Public Sub Main
      Dim s As String = "This is a string."
      Dim sub1 As String = "this"
      Console.WriteLine("Does '{0}' contain '{1}'?", s, sub1)
      Dim comp As StringComparison = StringComparison.Ordinal
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp))
      
      comp = StringComparison.OrdinalIgnoreCase
      Console.WriteLine("   {0:G}: {1}", comp, s.Contains(sub1, comp))
   End Sub
End Module
' The example displays the following output:
'       Does 'This is a string.' contain 'this'?
'          Ordinal: False
'          OrdinalIgnoreCase: True

如果您對目前實例中的子字串 value 位置感興趣，您可以呼叫 IndexOf 方法來取得其第一次出現的開始位置，或者您可以呼叫 LastIndexOf 方法來取得其最後一次出現的開始位置。 如果字串實例中找到子字串，此範例會包含方法的呼叫 IndexOf(String) 。

另請參閱

• IndexOf(Char)
• LastIndexOf(String)

來源:

String.Searching.cs

來源:

String.Searching.cs

來源:

String.Searching.cs

public:
 bool Contains(char value);

public bool Contains (char value);

member this.Contains : char -> bool

Public Function Contains (value As Char) As Boolean

參數

傳回

如果 value 參數出現在此字串內，則為 true；否則為 false。

備註

這個方法會執行序數 (區分大小寫且不區分文化特性) 比較。