String.StartsWith メソッド (String, Boolean, CultureInfo)
アセンブリ: mscorlib (mscorlib.dll 内)

Public Function StartsWith ( _ value As String, _ ignoreCase As Boolean, _ culture As CultureInfo _ ) As Boolean
Dim instance As String Dim value As String Dim ignoreCase As Boolean Dim culture As CultureInfo Dim returnValue As Boolean returnValue = instance.StartsWith(value, ignoreCase, culture)
public function StartsWith ( value : String, ignoreCase : boolean, culture : CultureInfo ) : boolean
- culture
この文字列と value との比較方法を決定するカルチャ情報。culture が null 参照 (Visual Basic では Nothing) の場合は、現在のカルチャが使用されます。
value パラメータがこの文字列の先頭と一致する場合は true。それ以外の場合は false。


このメソッドは、value パラメータと、この文字列の先頭にある、value とまったく同じ長さの部分文字列とを比較し、両者が等しいかどうかを示す値を返します。等しいという結果を得るためには、value が、空の文字列 (Empty) であるか、この同じインスタンスへの参照であるか、または、このインスタンスの先頭と一致している必要があります。
このメソッドは、大文字と小文字の区別とカルチャの種類を引数として受け取り、カルチャに依存する単語ベースの比較を実行します。

次に示すのは、ある文字列が別の文字列の先頭に出現するかどうかを調べるコード例です。StartsWith メソッドは、検索の結果に影響する大文字と小文字の区別の有無、およびさまざまなカルチャを指定して、複数回呼び出されます。

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。


String.StartsWith メソッド (String)
アセンブリ: mscorlib (mscorlib.dll 内)

Dim instance As String Dim value As String Dim returnValue As Boolean returnValue = instance.StartsWith(value)
戻り値
この文字列の先頭が value と一致する場合は true。それ以外の場合は false。


このメソッドは、value と、このインスタンスの先頭にある、value とまったく同じ長さの部分文字列とを比較し、両者が等しいかどうかを調べます。等しいという結果を得るためには、value が、空の文字列 (Empty) であるか、この同じインスタンスへの参照であるか、または、このインスタンスの先頭と一致している必要があります。

StartsWith メソッドを使用する方法を次のコード例に示します。
Imports System Public Class EndsWithTest Public Shared Sub Main() Dim strSource As String() = {"<b>This is bold text</b>", _ "<H1>This is large Text</H1>", _ "<b><i><font color = green>This has multiple tags</font></i></b>", _ "<b>This has <i>embedded</i> tags.</b>", _ "<This line simply begins with a lesser than symbol, it should not be modified"} ' process a string that contains html tags ' this sample does not remove embedded tags (tags in the middle of a line) Console.WriteLine("The following lists the items before the tags have been stripped:") Console.WriteLine("-----------------------------------------------------------------") ' print out the initial array of strings Dim s As String For Each s In strSource Console.WriteLine(s) Next s Console.WriteLine() Console.WriteLine("The following lists the items after the tags have been stripped:") Console.WriteLine("----------------------------------------------------------------") ' print out the array of strings For Each s In strSource Console.WriteLine(StripStartTags(s)) Next s End Sub 'Main Private Shared Function StripStartTags(item As String) As String ' try to find a tag at the start of the line using StartsWith If item.Trim().StartsWith("<") Then ' now search for the closing tag... Dim lastLocation As Integer = item.IndexOf(">") If lastLocation >= 0 Then ' remove the identified section, if it is a valid region item = item.Substring((lastLocation + 1)) End If End If Return item End Function 'StripStartTags End Class 'EndsWithTest
using System; public class EndsWithTest { public static void Main() { // process a string that contains html tags // this sample does not remove embedded tags (tags in the middle of a line) string [] strSource = { "<b>This is bold text</b>", "<H1>This is large Text</H1>", "<b><i><font color=green>This has multiple tags</font></i></b>", "<b>This has <i>embedded</i> tags.</b>" , "<This line simply begins with a lesser than symbol, it should not be modified" }; Console.WriteLine("The following lists the items before the tags have been stripped:"); Console.WriteLine("-----------------------------------------------------------------"); // print out the initial array of strings foreach ( string s in strSource ) Console.WriteLine( s ); Console.WriteLine(); Console.WriteLine("The following lists the items after the tags have been stripped:"); Console.WriteLine("----------------------------------------------------------------"); // print out the array of strings foreach ( string s in strSource ) Console.WriteLine( StripStartTags( s ) ); } private static string StripStartTags( string item ) { // try to find a tag at the start of the line using StartsWith if (item.Trim().StartsWith("<")) { // now search for the closing tag... int lastLocation = item.IndexOf( ">" ); // remove the identified section, if it is a valid region if ( lastLocation >= 0 ) item = item.Substring( lastLocation + 1 ); } return item; } }
using namespace System; using namespace System::Collections; String^ StripStartTags( String^ item ) { // try to find a tag at the start of the line using StartsWith if ( item->Trim()->StartsWith( "<" ) ) { // now search for the closing tag->->. int lastLocation = item->IndexOf( ">" ); // remove the identified section, if it is a valid region if ( lastLocation >= 0 ) item = item->Substring( lastLocation + 1 ); } return item; } int main() { // process a string that contains html tags // this sample does not remove embedded tags (tags in the middle of a line) array<String^>^strSource = {"<b>This is bold text</b>","<H1>This is large Text</H1>","<b><i><font color=green>This has multiple tags</font></i></b>","<b>This has <i>embedded</i> tags.</b>","<This line simply begins with a lesser than symbol, it should not be modified"}; Console::WriteLine( "The following lists the items before the tags have been stripped:" ); Console::WriteLine( "-----------------------------------------------------------------" ); // print out the initial array of strings IEnumerator^ myEnum1 = strSource->GetEnumerator(); while ( myEnum1->MoveNext() ) { String^ s = safe_cast<String^>(myEnum1->Current); Console::WriteLine( s ); } Console::WriteLine(); Console::WriteLine( "The following lists the items after the tags have been stripped:" ); Console::WriteLine( "----------------------------------------------------------------" ); // print [Out] the* array of strings IEnumerator^ myEnum2 = strSource->GetEnumerator(); while ( myEnum2->MoveNext() ) { String^ s = safe_cast<String^>(myEnum2->Current); Console::WriteLine( StripStartTags( s ) ); } }
import System.*; public class EndsWithTest { public static void main(String[] args) { // process a string that contains html tags // this sample does not remove embedded tags // (tags in the middle of a line) String strSource[] = { "<b>This is bold text</b>" , "<H1>This is large Text</H1>", "<b><i><font color=green>This has multiple tags</font></i></b>" , "<b>This has <i>embedded</i> tags.</b>" , "<This line simply begins with a lesser than symbol," + " it should not be modified" }; Console.WriteLine("The following lists the items before" + " the ends have been stripped:"); Console.WriteLine("-------------------------------------" + "----------------------------"); // print out the initial array of strings for (int iCtr = 0; iCtr < strSource.get_Length(); iCtr++) { String s = strSource[iCtr]; Console.WriteLine(s); } Console.WriteLine(); Console.WriteLine("The following lists the items after" + " the ends have been stripped:"); Console.WriteLine("---------------------------------------" + "-------------------------"); // print out the array of strings for (int iCtr = 0; iCtr < strSource.get_Length(); iCtr++) { String s = strSource[iCtr]; Console.WriteLine(StripStartTags(s)); } } //main private static String StripStartTags(String item) { // try to find a tag at the start of the line using StartsWith if (item.Trim().StartsWith("<")) { // now search for the closing tag... int lastLocation = item.IndexOf(">"); // remove the identified section, if it is a valid region if (lastLocation >= 0) { item = item.Substring(lastLocation + 1); } } return item; } //StripStartTags } //EndsWithTest
import System; public class EndsWithTest { public static function Main() : void { // process a string that contains html tags // this sample does not remove embedded tags (tags in the middle of a line) var strSource : String [] = [ "<b>This is bold text</b>", "<H1>This is large Text</H1>", "<b><i><font color=green>This has multiple tags</font></i></b>", "<b>This has <i>embedded</i> tags.</b>" , "<This line simply begins with a lesser than symbol, it should not be modified" ]; Console.WriteLine("The following lists the items before the tags have been stripped:"); Console.WriteLine("-----------------------------------------------------------------"); // print out the initial array of strings for( var i : int in strSource ) Console.WriteLine( strSource[i] ); Console.WriteLine(); Console.WriteLine("The following lists the items after the tags have been stripped:"); Console.WriteLine("----------------------------------------------------------------"); // print out the array of strings for ( i in strSource ) Console.WriteLine( StripStartTags( strSource[i] ) ); } private static function StripStartTags( item : String ) : String { // try to find a tag at the start of the line using StartsWith if (item.Trim().StartsWith("<")) { // now search for the closing tag... var lastLocation : int = item.IndexOf( ">" ); // remove the identified section, if it is a valid region if ( lastLocation >= 0 ) item = item.Substring( lastLocation + 1 ); } return item; } } EndsWithTest.Main();

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。


String.StartsWith メソッド (String, StringComparison)
アセンブリ: mscorlib (mscorlib.dll 内)

<ComVisibleAttribute(False)> _ Public Function StartsWith ( _ value As String, _ comparisonType As StringComparison _ ) As Boolean
Dim instance As String Dim value As String Dim comparisonType As StringComparison Dim returnValue As Boolean returnValue = instance.StartsWith(value, comparisonType)
[ComVisibleAttribute(false)] public bool StartsWith ( string value, StringComparison comparisonType )
[ComVisibleAttribute(false)] public: bool StartsWith ( String^ value, StringComparison comparisonType )
/** @attribute ComVisibleAttribute(false) */ public boolean StartsWith ( String value, StringComparison comparisonType )
ComVisibleAttribute(false) public function StartsWith ( value : String, comparisonType : StringComparison ) : boolean
戻り値
value パラメータがこの文字列の先頭と一致する場合は true。それ以外の場合は false。


StartsWith メソッドは、value パラメータと、この文字列の先頭にある部分文字列とを比較し、両者が等しいかどうかを示す値を返します。等しいという結果を得るためには、value が、この同じインスタンスへの参照であるか、空の文字列 ("") であるか、または、この文字列の先頭と一致している必要があります。StartsWith メソッドによって実行される比較の種類は、comparisonType パラメータの値に依存します。

ある文字列が特定の部分文字列で始まっているかどうかを判断するコード例を次に示します。選択したカルチャ、大文字と小文字の区別、比較の種類 (序数ベースにしたかどうか) が実行結果に影響します。
' This example demonstrates the ' System.String.StartsWith(String, StringComparison) method. Imports System Imports System.Threading Class Sample Public Shared Sub Main() Dim intro As String = "Determine whether a string starts with another string, " & _ "using" & vbCrLf & " different values of StringComparison." Dim scValues As StringComparison() = { _ StringComparison.CurrentCulture, _ StringComparison.CurrentCultureIgnoreCase, _ StringComparison.InvariantCulture, _ StringComparison.InvariantCultureIgnoreCase, _ StringComparison.Ordinal, _ StringComparison.OrdinalIgnoreCase } ' Console.Clear() Console.WriteLine(intro) ' Display the current culture because the culture-specific comparisons ' can produce different results with different cultures. Console.WriteLine("The current culture is {0}." & vbCrLf, _ Thread.CurrentThread.CurrentCulture.Name) ' Determine whether three versions of the letter I are equal to each other. Dim sc As StringComparison For Each sc In scValues Console.WriteLine("StringComparison.{0}:", sc) Test("ABCxyz", "ABC", sc) Test("ABCxyz", "abc", sc) Console.WriteLine() Next sc End Sub 'Main Protected Shared Sub Test(ByVal x As String, ByVal y As String, _ ByVal comparison As StringComparison) Dim resultFmt As String = """{0}"" {1} with ""{2}""." Dim result As String = "does not start" ' If x.StartsWith(y, comparison) Then result = "starts" End If Console.WriteLine(resultFmt, x, result, y) End Sub 'Test End Class 'Sample ' 'This code example produces the following results: ' 'Determine whether a string starts with another string, using ' different values of StringComparison. 'The current culture is en-US. ' 'StringComparison.CurrentCulture: '"ABCxyz" starts with "ABC". '"ABCxyz" does not start with "abc". ' 'StringComparison.CurrentCultureIgnoreCase: '"ABCxyz" starts with "ABC". '"ABCxyz" starts with "abc". ' 'StringComparison.InvariantCulture: '"ABCxyz" starts with "ABC". '"ABCxyz" does not start with "abc". ' 'StringComparison.InvariantCultureIgnoreCase: '"ABCxyz" starts with "ABC". '"ABCxyz" starts with "abc". ' 'StringComparison.Ordinal: '"ABCxyz" starts with "ABC". '"ABCxyz" does not start with "abc". ' 'StringComparison.OrdinalIgnoreCase: '"ABCxyz" starts with "ABC". '"ABCxyz" starts with "abc". '
// This example demonstrates the // System.String.StartsWith(String, StringComparison) method. using System; using System.Threading; class Sample { public static void Main() { string intro = "Determine whether a string starts with another string, " + "using\n different values of StringComparison."; StringComparison[] scValues = { StringComparison.CurrentCulture, StringComparison.CurrentCultureIgnoreCase, StringComparison.InvariantCulture, StringComparison.InvariantCultureIgnoreCase, StringComparison.Ordinal, StringComparison.OrdinalIgnoreCase }; // Console.Clear(); Console.WriteLine(intro); // Display the current culture because the culture-specific comparisons // can produce different results with different cultures. Console.WriteLine("The current culture is {0}.\n", Thread.CurrentThread.CurrentCulture.Name); // Determine whether three versions of the letter I are equal to each other. foreach (StringComparison sc in scValues) { Console.WriteLine("StringComparison.{0}:", sc); Test("ABCxyz", "ABC", sc); Test("ABCxyz", "abc", sc); Console.WriteLine(); } } protected static void Test(string x, string y, StringComparison comparison) { string resultFmt = "\"{0}\" {1} with \"{2}\"."; string result = "does not start"; // if (x.StartsWith(y, comparison)) result = "starts"; Console.WriteLine(resultFmt, x, result, y); } } /* This code example produces the following results: Determine whether a string starts with another string, using different values of StringComparison. The current culture is en-US. StringComparison.CurrentCulture: "ABCxyz" starts with "ABC". "ABCxyz" does not start with "abc". StringComparison.CurrentCultureIgnoreCase: "ABCxyz" starts with "ABC". "ABCxyz" starts with "abc". StringComparison.InvariantCulture: "ABCxyz" starts with "ABC". "ABCxyz" does not start with "abc". StringComparison.InvariantCultureIgnoreCase: "ABCxyz" starts with "ABC". "ABCxyz" starts with "abc". StringComparison.Ordinal: "ABCxyz" starts with "ABC". "ABCxyz" does not start with "abc". StringComparison.OrdinalIgnoreCase: "ABCxyz" starts with "ABC". "ABCxyz" starts with "abc". */
// This example demonstrates the // System::String->StartsWith(String, StringComparison) method. using namespace System; using namespace System::Threading; static void Test(String^ testString, String^ searchString, StringComparison comparison) { String^ resultFormat = "\"{0}\" {1} with \"{2}\"."; String^ resultString = "does not start"; if (testString->StartsWith(searchString, comparison)) { resultString = "starts"; } Console::WriteLine(resultFormat, testString, resultString, searchString); } int main() { String^ introMessage = "Determine whether a string starts with another string, " + "using\ndifferent values of StringComparison."; array<StringComparison>^ comparisonValues = { StringComparison::CurrentCulture, StringComparison::CurrentCultureIgnoreCase, StringComparison::InvariantCulture, StringComparison::InvariantCultureIgnoreCase, StringComparison::Ordinal, StringComparison::OrdinalIgnoreCase}; Console::Clear(); Console::WriteLine(introMessage); // Display the current culture because the culture-specific comparisons // can produce different results with different cultures. Console::WriteLine("The current culture is {0}.\n", Thread::CurrentThread->CurrentCulture->Name); // Perform two tests for each StringComparison for each(StringComparison stringCmp in comparisonValues) { Console::WriteLine("StringComparison.{0}:", stringCmp); Test("ABCxyz", "ABC", stringCmp); Test("ABCxyz", "abc", stringCmp); Console::WriteLine(); } } /* This code example produces the following results: Determine whether a string starts with another string, using different values of StringComparison. The current culture is en-US. StringComparison.CurrentCulture: "ABCxyz" starts with "ABC". "ABCxyz" does not start with "abc". StringComparison.CurrentCultureIgnoreCase: "ABCxyz" starts with "ABC". "ABCxyz" starts with "abc". StringComparison.InvariantCulture: "ABCxyz" starts with "ABC". "ABCxyz" does not start with "abc". StringComparison.InvariantCultureIgnoreCase: "ABCxyz" starts with "ABC". "ABCxyz" starts with "abc". StringComparison.Ordinal: "ABCxyz" starts with "ABC". "ABCxyz" does not start with "abc". StringComparison.OrdinalIgnoreCase: "ABCxyz" starts with "ABC". "ABCxyz" starts with "abc". */

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。


String.StartsWith メソッド

名前 | 説明 |
---|---|
String.StartsWith (String) | このインスタンスの先頭が、指定した文字列と一致するかどうかを判断します。 .NET Compact Framework によってサポートされています。 |
String.StartsWith (String, StringComparison) | 指定された比較オプションを使って比較した場合に、この文字列の先頭が、指定された文字列と一致するかどうかを判断します。 .NET Compact Framework によってサポートされています。 |
String.StartsWith (String, Boolean, CultureInfo) | 指定されたカルチャを使って比較した場合に、この文字列の先頭が、指定された文字列と一致するかどうかを判断します。 |

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