Char.CompareTo 方法
定義
比較這個執行個體與指定的物件或實值類型，並且指出這個執行個體在排序次序中，位於所指定物件或實值類型之前、之後或相同位置。Compares this instance to a specified object or value type, and indicates whether this instance precedes, follows, or appears in the same position in the sort order as the specified object or value type.
多載
| CompareTo(Char) |
比較這個執行個體與指定的 Char 物件，並且表示這個執行個體在排序次序中，位於所指定 Char 物件之前、之後或相同位置。Compares this instance to a specified Char object and indicates whether this instance precedes, follows, or appears in the same position in the sort order as the specified Char object. |
| CompareTo(Object) |
比較這個執行個體與指定的物件，並且表示這個執行個體在排序次序中，位於所指定 Object 之前、之後或相同位置。Compares this instance to a specified object and indicates whether this instance precedes, follows, or appears in the same position in the sort order as the specified Object. |
CompareTo(Char)
public:
virtual int CompareTo(char value);public int CompareTo (char value);abstract member CompareTo : char -> int
override this.CompareTo : char -> intPublic Function CompareTo (value As Char) As Integer參數
傳回
帶正負號的數字，指出這個執行個體在排序順序中的位置與 value 參數的相對關係。A signed number indicating the position of this instance in the sort order in relation to the value parameter.
| 傳回值Return Value | 描述Description |
|---|---|
| 小於零Less than zero | 這個執行個體位於 value 之前。This instance precedes value.
|
| 零Zero | 這個執行個體在排序次序中的位置與 value 相同。This instance has the same position in the sort order as value.
|
| 大於零Greater than zero | 這個執行個體位於 value 之後。This instance follows value.
|
實作
範例
下列程式碼範例將示範 CompareTo 數個值和參考型別之方法的泛型和非泛型版本。The following code example demonstrates generic and non-generic versions of the CompareTo method for several value and reference types.
// This example demonstrates the two versions of the
// CompareTo method for several base types.
// The general version takes a parameter of type Object, while the specific
// version takes a type-specific parameter, such as Boolean, Int32, or Double.
using namespace System;
void Show( String^ caption, Object^ var1, Object^ var2, int resultGeneric, int resultNonGeneric )
{
String^ relation;
Console::Write( caption );
if ( resultGeneric == resultNonGeneric )
{
if ( resultGeneric < 0 )
relation = "less than";
else
if ( resultGeneric > 0 )
relation = "greater than";
else
relation = "equal to";
Console::WriteLine( "{0} is {1} {2}", var1, relation, var2 );
}
// The following condition will never occur because the generic and non-generic
// CompareTo methods are equivalent.
else
{
Console::WriteLine( "Generic CompareTo = {0}; non-generic CompareTo = {1}", resultGeneric, resultNonGeneric );
}
}
int main()
{
String^ nl = Environment::NewLine;
String^ msg = "{0}The following is the result of using the generic and non-generic{0}"
"versions of the CompareTo method for several base types:{0}";
Object^ obj; // An Object used to insure CompareTo(Object) is called.
DateTime now = DateTime::Now;
// Time span = 11 days, 22 hours, 33 minutes, 44 seconds
TimeSpan tsX = TimeSpan(11,22,33,44);
// Version = 1.2.333.4
Version^ versX = gcnew Version( "1.2.333.4" );
// Guid = CA761232-ED42-11CE-BACD-00AA0057B223
Guid guidX = Guid( "{CA761232-ED42-11CE-BACD-00AA0057B223}");
Boolean a1 = true,a2 = true;
Byte b1 = 1,b2 = 1;
Int16 c1 = -2,c2 = 2;
Int32 d1 = 3,d2 = 3;
Int64 e1 = 4,e2 = -4;
Decimal f1 = Decimal(-5.5), f2 = Decimal(5.5);
Single g1 = 6.6f,g2 = 6.6f;
Double h1 = 7.7,h2 = -7.7;
Char i1 = 'A',i2 = 'A';
String^ j1 = "abc", ^j2 = "abc";
DateTime k1 = now,k2 = now;
TimeSpan l1 = tsX,l2 = tsX;
Version^ m1 = versX, ^m2 = gcnew Version( "2.0" );
Guid n1 = guidX,n2 = guidX;
// The following types are not CLS-compliant.
SByte w1 = 8,w2 = 8;
UInt16 x1 = 9,x2 = 9;
UInt32 y1 = 10,y2 = 10;
UInt64 z1 = 11,z2 = 11;
//
Console::WriteLine( msg, nl );
try
{
Show( "Boolean: ", a1, a2, a1.CompareTo( a2 ), a1.CompareTo( a2 ) );
Show( "Byte: ", b1, b2, b1.CompareTo( b2 ), b1.CompareTo( b2 ) );
Show( "Int16: ", c1, c2, c1.CompareTo( c2 ), c1.CompareTo( c2 ) );
Show( "Int32: ", d1, d2, d1.CompareTo( d2 ), d1.CompareTo( d2 ) );
Show( "Int64: ", e1, e2, e1.CompareTo( e2 ), e1.CompareTo( e2 ) );
Show( "Decimal: ", f1, f2, f1.CompareTo( f2 ), f1.CompareTo( f2 ) );
Show( "Single: ", g1, g2, g1.CompareTo( g2 ), g1.CompareTo( g2 ) );
Show( "Double: ", h1, h2, h1.CompareTo( h2 ), h1.CompareTo( h2 ) );
Show( "Char: ", i1, i2, i1.CompareTo( i2 ), i1.CompareTo( i2 ) );
// Use an anonymous object to hide the String object.
obj = j2;
Show( "String: ", j1, j2, j1->CompareTo( j2 ), j1->CompareTo( obj ) );
Show( "DateTime:", k1, k2, k1.CompareTo( k2 ), k1.CompareTo( k2 ) );
Show( "TimeSpan: ", l1, l2, l1.CompareTo( l2 ), l1.CompareTo( l2 ) );
// Use an anonymous object to hide the Version object.
obj = m2;
Show( "Version: ", m1, m2, m1->CompareTo( m2 ), m1->CompareTo( obj ) );
Show( "Guid: ", n1, n2, n1.CompareTo( n2 ), n1.CompareTo( n2 ) );
//
Console::WriteLine( "{0}The following types are not CLS-compliant:", nl );
Show( "SByte: ", w1, w2, w1.CompareTo( w2 ), w1.CompareTo( w2 ) );
Show( "UInt16: ", x1, x2, x1.CompareTo( x2 ), x1.CompareTo( x2 ) );
Show( "UInt32: ", y1, y2, y1.CompareTo( y2 ), y1.CompareTo( y2 ) );
Show( "UInt64: ", z1, z2, z1.CompareTo( z2 ), z1.CompareTo( z2 ) );
}
catch ( Exception^ e )
{
Console::WriteLine( e );
}
}
// This example displays the following output:
//
// The following is the result of using the generic and non-generic versions of the
// CompareTo method for several base types:
//
// Boolean: True is equal to True
// Byte: 1 is equal to 1
// Int16: -2 is less than 2
// Int32: 3 is equal to 3
// Int64: 4 is greater than -4
// Decimal: -5.5 is less than 5.5
// Single: 6.6 is equal to 6.6
// Double: 7.7 is greater than -7.7
// Char: A is equal to A
// String: abc is equal to abc
// DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
// TimeSpan: 11.22:33:44 is equal to 11.22:33:44
// Version: 1.2.333.4 is less than 2.0
// Guid: ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
// aa0057b223
//
// The following types are not CLS-compliant:
// SByte: 8 is equal to 8
// UInt16: 9 is equal to 9
// UInt32: 10 is equal to 10
// UInt64: 11 is equal to 11
// This example demonstrates the generic and non-generic versions of the
// CompareTo method for several base types.
// The non-generic version takes a parameter of type Object, while the generic
// version takes a type-specific parameter, such as Boolean, Int32, or Double.
using System;
class Sample
{
public static void Main()
{
string nl = Environment.NewLine;
string msg = "{0}The following is the result of using the generic and non-generic{0}" +
"versions of the CompareTo method for several base types:{0}";
DateTime now = DateTime.Now;
// Time span = 11 days, 22 hours, 33 minutes, 44 seconds
TimeSpan tsX = new TimeSpan(11, 22, 33, 44);
// Version = 1.2.333.4
Version versX = new Version("1.2.333.4");
// Guid = CA761232-ED42-11CE-BACD-00AA0057B223
Guid guidX = new Guid("{CA761232-ED42-11CE-BACD-00AA0057B223}");
Boolean a1 = true, a2 = true;
Byte b1 = 1, b2 = 1;
Int16 c1 = -2, c2 = 2;
Int32 d1 = 3, d2 = 3;
Int64 e1 = 4, e2 = -4;
Decimal f1 = -5.5m, f2 = 5.5m;
Single g1 = 6.6f, g2 = 6.6f;
Double h1 = 7.7d, h2 = -7.7d;
Char i1 = 'A', i2 = 'A';
String j1 = "abc", j2 = "abc";
DateTime k1 = now, k2 = now;
TimeSpan l1 = tsX, l2 = tsX;
Version m1 = versX, m2 = new Version("2.0");
Guid n1 = guidX, n2 = guidX;
// The following types are not CLS-compliant.
SByte w1 = 8, w2 = 8;
UInt16 x1 = 9, x2 = 9;
UInt32 y1 = 10, y2 = 10;
UInt64 z1 = 11, z2 = 11;
//
Console.WriteLine(msg, nl);
try
{
// The second and third Show method call parameters are automatically boxed because
// the second and third Show method declaration arguments expect type Object.
Show("Boolean: ", a1, a2, a1.CompareTo(a2), a1.CompareTo((Object)a2));
Show("Byte: ", b1, b2, b1.CompareTo(b2), b1.CompareTo((Object)b2));
Show("Int16: ", c1, c2, c1.CompareTo(c2), c1.CompareTo((Object)c2));
Show("Int32: ", d1, d2, d1.CompareTo(d2), d1.CompareTo((Object)d2));
Show("Int64: ", e1, e2, e1.CompareTo(e2), e1.CompareTo((Object)e2));
Show("Decimal: ", f1, f2, f1.CompareTo(f2), f1.CompareTo((Object)f2));
Show("Single: ", g1, g2, g1.CompareTo(g2), g1.CompareTo((Object)g2));
Show("Double: ", h1, h2, h1.CompareTo(h2), h1.CompareTo((Object)h2));
Show("Char: ", i1, i2, i1.CompareTo(i2), i1.CompareTo((Object)i2));
Show("String: ", j1, j2, j1.CompareTo(j2), j1.CompareTo((Object)j2));
Show("DateTime: ", k1, k2, k1.CompareTo(k2), k1.CompareTo((Object)k2));
Show("TimeSpan: ", l1, l2, l1.CompareTo(l2), l1.CompareTo((Object)l2));
Show("Version: ", m1, m2, m1.CompareTo(m2), m1.CompareTo((Object)m2));
Show("Guid: ", n1, n2, n1.CompareTo(n2), n1.CompareTo((Object)n2));
//
Console.WriteLine("{0}The following types are not CLS-compliant:", nl);
Show("SByte: ", w1, w2, w1.CompareTo(w2), w1.CompareTo((Object)w2));
Show("UInt16: ", x1, x2, x1.CompareTo(x2), x1.CompareTo((Object)x2));
Show("UInt32: ", y1, y2, y1.CompareTo(y2), y1.CompareTo((Object)y2));
Show("UInt64: ", z1, z2, z1.CompareTo(z2), z1.CompareTo((Object)z2));
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
public static void Show(string caption, Object var1, Object var2,
int resultGeneric, int resultNonGeneric)
{
string relation;
Console.Write(caption);
if (resultGeneric == resultNonGeneric)
{
if (resultGeneric < 0) relation = "less than";
else if (resultGeneric > 0) relation = "greater than";
else relation = "equal to";
Console.WriteLine("{0} is {1} {2}", var1, relation, var2);
}
// The following condition will never occur because the generic and non-generic
// CompareTo methods are equivalent.
else
{
Console.WriteLine("Generic CompareTo = {0}; non-generic CompareTo = {1}",
resultGeneric, resultNonGeneric);
}
}
}
/*
This example produces the following results:
The following is the result of using the generic and non-generic versions of the
CompareTo method for several base types:
Boolean: True is equal to True
Byte: 1 is equal to 1
Int16: -2 is less than 2
Int32: 3 is equal to 3
Int64: 4 is greater than -4
Decimal: -5.5 is less than 5.5
Single: 6.6 is equal to 6.6
Double: 7.7 is greater than -7.7
Char: A is equal to A
String: abc is equal to abc
DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
TimeSpan: 11.22:33:44 is equal to 11.22:33:44
Version: 1.2.333.4 is less than 2.0
Guid: ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
aa0057b223
The following types are not CLS-compliant:
SByte: 8 is equal to 8
UInt16: 9 is equal to 9
UInt32: 10 is equal to 10
UInt64: 11 is equal to 11
*/
' This example demonstrates the generic and non-generic versions of the
' CompareTo method for several base types.
' The non-generic version takes a parameter of type Object, while the generic
' version takes a type-specific parameter, such as Boolean, Int32, or Double.
Class Sample
Public Shared Sub Main()
Dim nl As String = Environment.NewLine
Dim msg As String = _
"{0}The following is the result of using the generic and non-generic{0}" & _
"versions of the CompareTo method for several base types:{0}"
Dim now As DateTime = DateTime.Now
' Time span = 11 days, 22 hours, 33 minutes, 44 seconds
Dim tsX As New TimeSpan(11, 22, 33, 44)
' Version = 1.2.333.4
Dim versX As New Version("1.2.333.4")
' Guid = CA761232-ED42-11CE-BACD-00AA0057B223
Dim guidX As New Guid("{CA761232-ED42-11CE-BACD-00AA0057B223}")
Dim a1 As [Boolean] = True, a2 As [Boolean] = True
Dim b1 As [Byte] = 1, b2 As [Byte] = 1
Dim c1 As Int16 = -2, c2 As Int16 = 2
Dim d1 As Int32 = 3, d2 As Int32 = 3
Dim e1 As Int64 = 4, e2 As Int64 = -4
Dim f1 As [Decimal] = -5.5D, f2 As [Decimal] = 5.5D
Dim g1 As [Single] = 6.6F, g2 As [Single] = 6.6F
Dim h1 As [Double] = 7.7, h2 As [Double] = -7.7
Dim i1 As [Char] = "A"c, i2 As [Char] = "A"c
Dim j1 As String = "abc", j2 As String = "abc"
Dim k1 As DateTime = now, k2 As DateTime = now
Dim l1 As TimeSpan = tsX, l2 As TimeSpan = tsX
Dim m1 As Version = versX, m2 As New Version("2.0")
Dim n1 As Guid = guidX, n2 As Guid = guidX
' The following types are not CLS-compliant.
' SByte, UInt16, UInt32, UInt64
Console.WriteLine(msg, nl)
Try
' The second and third Show method call parameters are automatically boxed because
' the second and third Show method declaration arguments expect type Object.
Show("Boolean: ", a1, a2, a1.CompareTo(a2), a1.CompareTo(CObj(a2)))
Show("Byte: ", b1, b2, b1.CompareTo(b2), b1.CompareTo(CObj(b2)))
Show("Int16: ", c1, c2, c1.CompareTo(c2), c1.CompareTo(CObj(c2)))
Show("Int32: ", d1, d2, d1.CompareTo(d2), d1.CompareTo(CObj(d2)))
Show("Int64: ", e1, e2, e1.CompareTo(e2), e1.CompareTo(CObj(e2)))
Show("Decimal: ", f1, f2, f1.CompareTo(f2), f1.CompareTo(CObj(f2)))
Show("Single: ", g1, g2, g1.CompareTo(g2), g1.CompareTo(CObj(g2)))
Show("Double: ", h1, h2, h1.CompareTo(h2), h1.CompareTo(CObj(h2)))
Show("Char: ", i1, i2, i1.CompareTo(i2), i1.CompareTo(CObj(i2)))
Show("String: ", j1, j2, j1.CompareTo(j2), j1.CompareTo(CObj(j2)))
Show("DateTime: ", k1, k2, k1.CompareTo(k2), k1.CompareTo(CObj(k2)))
Show("TimeSpan: ", l1, l2, l1.CompareTo(l2), l1.CompareTo(CObj(l2)))
Show("Version: ", m1, m2, m1.CompareTo(m2), m1.CompareTo(CObj(m2)))
Show("Guid: ", n1, n2, n1.CompareTo(n2), n1.CompareTo(CObj(n2)))
'
Console.WriteLine("{0}The following types are not CLS-compliant:", nl)
Console.WriteLine("SByte, UInt16, UInt32, UInt64")
Catch e As Exception
Console.WriteLine(e)
End Try
End Sub
Public Shared Sub Show(caption As String, var1 As [Object], var2 As [Object], _
resultGeneric As Integer, resultNonGeneric As Integer)
Dim relation As String
Console.Write(caption)
If resultGeneric = resultNonGeneric Then
If resultGeneric < 0 Then
relation = "less than"
ElseIf resultGeneric > 0 Then
relation = "greater than"
Else
relation = "equal to"
End If
Console.WriteLine("{0} is {1} {2}", var1, relation, var2)
' The following condition will never occur because the generic and non-generic
' CompareTo methods are equivalent.
Else
Console.WriteLine("Generic CompareTo = {0}; non-generic CompareTo = {1}", _
resultGeneric, resultNonGeneric)
End If
End Sub
End Class
'
'This example produces the following results:
'
'The following is the result of using the generic and non-generic versions of the
'CompareTo method for several base types:
'
'Boolean: True is equal to True
'Byte: 1 is equal to 1
'Int16: -2 is less than 2
'Int32: 3 is equal to 3
'Int64: 4 is greater than -4
'Decimal: -5.5 is less than 5.5
'Single: 6.6 is equal to 6.6
'Double: 7.7 is greater than -7.7
'Char: A is equal to A
'String: abc is equal to abc
'DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
'TimeSpan: 11.22:33:44 is equal to 11.22:33:44
'Version: 1.2.333.4 is less than 2.0
'Guid: ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
'aa0057b223
'
'The following types are not CLS-compliant:
'SByte, UInt16, UInt32, UInt64
'
備註
這個方法會實作為 System.IComparable<T> 介面，而且執行方式稍微優於 Char.CompareTo 方法，因為它不需要將 value 參數轉換成物件。This method implements the System.IComparable<T> interface and performs slightly better than the Char.CompareTo method because it does not have to convert the value parameter to an object.
這個方法所執行的比較是以這個實例的編碼值為基礎，而不是以 value 其字典的特性為基礎。The comparison performed by this method is based on the encoded values of this instance and value, not their lexicographical characteristics.
如果 CompareTo 方法參數類型的位較少 (比實例類型更窄) ，某些程式設計語言會執行隱含擴輾轉換，將參數值轉換為具有更多位的值。If the CompareTo method parameter type has fewer bits (is narrower) than the instance type, some programming languages perform an implicit widening conversion that transforms the value of the parameter into a value with more bits.
例如，假設實例型別是 Int32 ，而且參數類型是 Byte 。For example, suppose the instance type is Int32 and the parameter type is Byte. Microsoft c # 編譯器會產生指示，將參數的值表示為 Int32 物件，然後產生 Int32.CompareTo 會比較 Int32 實例和 Int32 參數標記法值的方法。The Microsoft C# compiler generates instructions to represent the value of the parameter as an Int32 object, then generates a Int32.CompareTo method that compares the values of the Int32 instance and the Int32 parameter representation.
一般而言，隱含擴輾轉換會在數數值型別上執行。Typically, implicit widening conversions are performed on numeric types. 請參閱程式設計語言的檔，以判斷其編譯器是否執行擴輾轉換。Consult your programming language's documentation to determine if its compiler performs widening conversions. 如果實例和參數類型不符，而且無法使用適當的轉換，則編譯器會產生 box 參數的指示，並叫 CompareTo 用採用參數的多載 Object 。If the instance and parameter types mismatch and a suitable conversion is not available, the compiler generates instructions to box the parameter and invoke the CompareTo overload that takes an Object parameter.
另請參閱
適用於
CompareTo(Object)
public:
virtual int CompareTo(System::Object ^ value);public int CompareTo (object? value);public int CompareTo (object value);abstract member CompareTo : obj -> int
override this.CompareTo : obj -> intPublic Function CompareTo (value As Object) As Integer參數
- value
- Object
要與這個執行個體相比較的物件，或 null。An object to compare this instance to, or null.
傳回
帶正負號的數字，指出這個執行個體在排序順序中的位置與 value 參數的相對關係。A signed number indicating the position of this instance in the sort order in relation to the value parameter.
| 傳回值Return Value | 描述Description |
|---|---|
| 小於零Less than zero | 這個執行個體位於 value 之前。This instance precedes value.
|
| 零Zero | 這個執行個體在排序次序中的位置與 value 相同。This instance has the same position in the sort order as value.
|
| 大於零Greater than zero | 這個執行個體位於 value 之後。This instance follows value.
-或--or-
|
實作
例外狀況
範例
下列程式碼範例將示範 CompareTo 。The following code example demonstrates CompareTo.
using namespace System;
int main()
{
char chA = 'A';
char chB = 'B';
Console::WriteLine( chA.CompareTo( 'A' ) ); // Output: "0" (meaning they're equal)
Console::WriteLine( 'b'.CompareTo( chB ) ); // Output: "32" (meaning 'b' is greater than 'B' by 32)
Console::WriteLine( chA.CompareTo( chB ) ); // Output: "-1" (meaning 'A' is less than 'B' by 1)
}
using System;
public class CompareToSample {
public static void Main() {
char chA = 'A';
char chB = 'B';
Console.WriteLine(chA.CompareTo('A')); // Output: "0" (meaning they're equal)
Console.WriteLine('b'.CompareTo(chB)); // Output: "32" (meaning 'b' is greater than 'B' by 32)
Console.WriteLine(chA.CompareTo(chB)); // Output: "-1" (meaning 'A' is less than 'B' by 1)
}
}
Module CompareToSample
Sub Main()
Dim chA As Char
chA = "A"c
Dim chB As Char
chB = "B"c
Console.WriteLine(chA.CompareTo("A"c)) ' Output: "0" (meaning they're equal)
Console.WriteLine("b"c.CompareTo(chB)) ' Output: "32" (meaning 'b' is 32 greater than 'B')
Console.WriteLine(chA.CompareTo(chB)) ' Output: "-1" (meaning 'A' is less than 'B' by 1)
End Sub
End Module
備註
方法會實 CompareTo 作為 IComparable 介面。The CompareTo method implements the IComparable interface.
value參數必須是 null 或的實例 Char ，否則會擲回例外狀況。The value parameter must be null or an instance of Char; otherwise, an exception is thrown.
這個方法所執行的比較是以這個實例的編碼值為基礎 value ，而不一定是其字典式特性。The comparison performed by this method is based on the encoded values of this instance and value, not necessarily their lexicographical characteristics. Char無論其值為何，都會將任何實例視為大於 null 。Any instance of Char, regardless of its value, is considered greater than null.