Class StringExtensions

string 扩展方法

Inheritance

Object

StringExtensions

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Lett.Extensions

Assembly: Lett.Extensions.dll

Syntax

public static class StringExtensions

Methods

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AppendPrefixIfNotExist(String, String, StringComparison)

如果字符串不包含指定前缀，则添加前缀

默认不区分大小写

Declaration

public static string AppendPrefixIfNotExist(this string this, string prefix, StringComparison stringComparison = StringComparison.OrdinalIgnoreCase)

Parameters

Type	Name	Description
String	this
String	prefix	前缀
StringComparison	stringComparison	字符串比较规则默认使用 OrdinalIgnoreCase

Returns

Type	Description
String

Examples

var rs1  = "aa".AppendPrefixIfNotExist("t_");                               // t_aa

var rs2  = "T_bb".AppendPrefixIfNotExist("t_");                             // T_bb

var rs3  = "T_cc".AppendPrefixIfNotExist("t_", StringComparison.Ordinal);   // t_T_cc

"T_cc".AppendPrefixIfNotExist(null);         // throw ArgumentNullException  prefix is null

default(string).AppendPrefixIfNotExist("d"); // throw ArgumentNullException  @this is null

Exceptions

Type	Condition
ArgumentNullException	`this` 不允许为空
ArgumentNullException	`prefix` 不允许为空

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AppendSuffixIfNotExist(String, String, StringComparison)

如果字符串不包含指定后缀，则添加后缀

默认不区分大小写

Declaration

public static string AppendSuffixIfNotExist(this string this, string suffix, StringComparison stringComparison = StringComparison.OrdinalIgnoreCase)

Parameters

Type	Name	Description
String	this
String	suffix	后缀
StringComparison	stringComparison	字符串比较规则默认使用 OrdinalIgnoreCase

Returns

Type	Description
String

Examples

var rs1  = "aa".AppendSuffixIfNotExist("_t");                               // aa_t

var rs2  = "bb_T".AppendSuffixIfNotExist("_t");                             // bb_T

var rs3  = "cc_T".AppendSuffixIfNotExist("_t", StringComparison.Ordinal);   // cc_T_t

"cc_T".AppendSuffixIfNotExist(null);            // throw ArgumentNullException suffix is null

default(string).AppendSuffixIfNotExist("_t");   // throw ArgumentNullException @this is null

Exceptions

Type	Condition
ArgumentNullException	`this` 不允许为空
ArgumentNullException	`suffix` 不允许为空

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AsDirectoryInfo(String)

转换为 DirectoryInfo (当前字符串作为 path)

Declaration

public static DirectoryInfo AsDirectoryInfo(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
DirectoryInfo

Exceptions

Type	Condition
ArgumentNullException

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AsFileStream(String, FileMode, FileAccess, FileShare, Int32)

转换为 FileStream (当前字符串作为 path)

Declaration

public static FileStream AsFileStream(this string this, FileMode fileMode, FileAccess fileAccess, FileShare fileShare, int bufferSize = 8192)

Parameters

Type	Name	Description
String	this
FileMode	fileMode	文件打开方式
FileAccess	fileAccess
FileShare	fileShare
Int32	bufferSize	缓冲区大小

Returns

Type	Description
FileStream

Exceptions

Type	Condition
ArgumentNullException	`@this` is null.
ArgumentException	`@this` is an empty string (""), contains only white space, or contains one or more invalid characters. -or- `this` refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment.
NotSupportedException	`@this` refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment.
FileNotFoundException	The file cannot be found, such as when `fileMode` is FileMode.Truncate or FileMode.Open, and the file specified by `this` does not exist. The file must already exist in these modes.
IOException	An I/O error, such as specifying FileMode.CreateNew when the file specified by `this` already exists, occurred. -or- The system is running Windows 98 or Windows 98 Second Edition and `fileShare` is set to FileShare.Delete. -or- The stream has been closed.
SecurityException	The caller does not have the required permission.
DirectoryNotFoundException	The specified path is invalid, such as being on an unmapped drive.
UnauthorizedAccessException	The `fileAccess` requested is not permitted by the operating system for the specified `this`, such as when `fileAccess` is Write or ReadWrite and the file or directory is set for read-only access.
PathTooLongException	The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

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Base64Decode(String)

进行 BASE6 4解码

使用 UTF8

Declaration

public static string Base64Decode(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
String	转换失败返回 `null`

Examples

var base64 = "QUJDRA==";
base64.Base64Decode(); // "ABCD"

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Base64Encode(String)

进行 BASE64 编码

使用 UTF8

Declaration

public static string Base64Encode(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
String	转换失败返回 `null`

Examples

var str1   = "ABCD";
str1.Base64Encode(); // "QUJDRA=="

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ContainsAll(String, IEnumerable<String>)

是否全部包含

使用 CurrentCultureIgnoreCase 比较

Declaration

public static bool ContainsAll(this string this, IEnumerable<string> values)

Parameters

Type	Name	Description
String	this
IEnumerable<String>	values	需要进行判断的字符串集合

Returns

Type	Description
Boolean

Examples

var a = "aaabbbccc";
var b = new[] {"aaa", "bbb"};
a.ContainsAll(b);  // true

Exceptions

Type	Condition
ArgumentNullException	`values` is null
ArgumentException

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ContainsAll(String, IEnumerable<String>, StringComparison)

是否全部包含

Declaration

public static bool ContainsAll(this string this, IEnumerable<string> values, StringComparison comparisonType)

Parameters

Type	Name	Description
String	this
IEnumerable<String>	values	需要进行判断的字符串集合
StringComparison	comparisonType	字符串比较规则

Returns

Type	Description
Boolean

Examples

var a = "aaabbbccc";
var b = new[] {"aaa", "bbb"};
a.ContainsAll(b);  // true

Exceptions

Type	Condition
ArgumentNullException	`values` is null
ArgumentException

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ContainsAny(String, IEnumerable<String>)

是否包含任意一个

使用 CurrentCultureIgnoreCase 判断

Declaration

public static bool ContainsAny(this string this, IEnumerable<string> values)

Parameters

Type	Name	Description
String	this
IEnumerable<String>	values	需要进行判断的字符串集合

Returns

Type	Description
Boolean

Examples

var a = "aaabbbccc";
var b = new[] {"a", "dd", "eee"};
a.ContainsAny(b); // true

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ContainsAny(String, IEnumerable<String>, StringComparison)

是否包含任意一个

Declaration

public static bool ContainsAny(this string this, IEnumerable<string> values, StringComparison comparisonType)

Parameters

Type	Name	Description
String	this
IEnumerable<String>	values	需要进行判断的字符串集合
StringComparison	comparisonType	字符串比较规则

Returns

Type	Description
Boolean

Examples

var a = "aaabbbccc";
var b = new[] {"a", "dd", "eee"};
a.ContainsAny(b); // true

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Format(String, Object[])

格式化

Declaration

public static string Format(this string this, params object[] args)

Parameters

Type	Name	Description
String	this
Object[]	args

Returns

Type	Description
String

Examples

var tmp = "{0}-{1}";
tmp.Format(new[]{"aaa","bbb"}); // "aaa-bbb"

Exceptions

Type	Condition
ArgumentNullException
FormatException

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IgnoreCaseEquals(String, String)

忽略大小写比较

使用 CurrentCultureIgnoreCase

Declaration

public static bool IgnoreCaseEquals(this string this, string value)

Parameters

Type	Name	Description
String	this
String	value	需要进行比较的字符串

Returns

Type	Description
Boolean

Examples

"aaa".IgnoreCaseEquals("AaA"); // true

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IsEmail(String)

是否Email

Declaration

public static bool IsEmail(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

"abc@qqq.com".IsEmail();  // true
"abc@qqq#.com".IsEmail(); // false

Exceptions

Type	Condition
ArgumentNullException	字符串为空
ArgumentNullException
ArgumentException
RegexMatchTimeoutException

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IsEmpty(String)

是否空字符串

Declaration

public static bool IsEmpty(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

var a = "";
var b = " ";

a.IsEmpty(); // true
b.IsEmpty(); // false

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IsLike(String, String)

使用通配符比较字符串是否相似

通配符 *

特殊字符用 \ 转义

正则匹配时，使用 Singleline

Declaration

public static bool IsLike(this string this, string pattern)

Parameters

Type	Name	Description
String	this
String	pattern	通配符表达式，为 null 时返回 false

Returns

Type	Description
Boolean	`this`为 null 时返回 false `pattern`为 null 时返回 false

Examples

var test1 = "abcdefg\r\nabcdefghijk";
test1.IsLike("abc*");     // true
test1.IsLike("a*");       // true
test1.IsLike("*ijk");     // true
test1.IsLike("abc*fg*");  // true

Exceptions

Type	Condition
ArgumentOutOfRangeException
ArgumentNullException
FormatException
ArgumentException
RegexMatchTimeoutException

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IsLower(String)

是否全部小写

Declaration

public static bool IsLower(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

"abcddd".IsLower(); // true;
"abDD".IsLower();   // false

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IsNullOrEmpty(String)

是否 null 或 string.Empty

Declaration

public static bool IsNullOrEmpty(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

" ".IsNullOrEmpty(); // false
"".IsNullOrEmpty();  // true

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IsNullOrWhiteSpace(String)

是否null或空白

Declaration

public static bool IsNullOrWhiteSpace(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

"   ".IsNullOrWhiteSpace(); // true
"\r".IsNullOrWhiteSpace();  // true

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IsUpper(String)

是否全部大写

Declaration

public static bool IsUpper(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

"ABC".IsUpper(); // true
"ABd".IsUpper(); // false

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IsUrl(String)

是否URL

Declaration

public static bool IsUrl(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

"http://sdf.com".IsUrl(); // true
"http://sdf.c.dddd.cccc.saaa.com".IsUrl(); // true
"www.sdf.com".IsUrl(); // false

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IsWhiteSpace(String)

是否空白字符串

Declaration

public static bool IsWhiteSpace(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Boolean

Examples

var a = "";
var b = " ";
var c = "\r";
var d = "\t";
var e = "\n";
var f = "\r \t";

a.IsWhiteSpace(); // true
b.IsWhiteSpace(); // true
c.IsWhiteSpace(); // true
d.IsWhiteSpace(); // true
e.IsWhiteSpace(); // true
f.IsWhiteSpace(); // true

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Left(String, Int32)

从左侧返回指定长度的字符串

Declaration

public static string Left(this string this, int length)

Parameters

Type	Name	Description
String	this
Int32	length	指定长度不能小于 0

Returns

Type	Description
String

Examples

"1234567890".Left(3); // "123"

Exceptions

Type	Condition
ArgumentOutOfRangeException	`length` 不能小于 0

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RegexIsMatch(String, String)

正则表达式 - 是否匹配

使用None

Declaration

public static bool RegexIsMatch(this string this, string pattern)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式

Returns

Type	Description
Boolean

Examples

var source = "abcdefg\r\nabcdefghijk";
source.RegexIsMatch(@"^abc.*\r$", RegexOptions.Multiline); // true

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException
RegexMatchTimeoutException

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RegexIsMatch(String, String, RegexOptions)

正则表达式 - 是否匹配

Declaration

public static bool RegexIsMatch(this string this, string pattern, RegexOptions regexOption)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式
RegexOptions	regexOption	正则表达式选项

Returns

Type	Description
Boolean

Examples

var source = "abcdefg\r\nabcdefghijk";
source.RegexIsMatch(@"^abc.*\r$", RegexOptions.Multiline); // true

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException
RegexMatchTimeoutException

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RegexMatch(String, String)

正则表达式 - 单个匹配对象

使用 None

Declaration

public static Match RegexMatch(this string this, string pattern)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式

Returns

Type	Description
Match	单个匹配对象

Examples

var str = "aaaabaaaabaaaa";
var match = str.RegexMatch("b"); // match.Success == true;

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException
RegexMatchTimeoutException

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RegexMatch(String, String, RegexOptions)

正则表达式 - 单个匹配对象

Declaration

public static Match RegexMatch(this string this, string pattern, RegexOptions regexOption)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式
RegexOptions	regexOption	正则表达式选项

Returns

Type	Description
Match	单个匹配对象

Examples

var str = "aaaabaaaabaaaa";
var match = str.RegexMatch("b"); // match.Success == true;

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException
RegexMatchTimeoutException

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RegexMatches(String, String)

正则表达式 - 所有匹配对象

使用 None

Declaration

public static MatchCollection RegexMatches(this string this, string pattern)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式

Returns

Type	Description
MatchCollection	所有匹配对象

Examples

var str   = "aaaabaaaabaaaa";
var matches = str.RegexMatches(@"aaaab");  // matches.Count == 2

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException

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RegexMatches(String, String, RegexOptions)

正则表达式 - 所有匹配对象

Declaration

public static MatchCollection RegexMatches(this string this, string pattern, RegexOptions regexOption)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式
RegexOptions	regexOption	正则表达式选项

Returns

Type	Description
MatchCollection	所有匹配对象

Examples

var str   = "aaaabaaaabaaaa";
var matches = str.RegexMatches(@"aaaab");  // matches.Count == 2

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException

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RegexReplace(String, String, String)

正则表达式 - 替换字符串

使用 None

Declaration

public static string RegexReplace(this string this, string pattern, string replacement)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式
String	replacement	替换字符串

Returns

Type	Description
String

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RegexReplace(String, String, String, RegexOptions)

正则表达式 - 替换字符串

Declaration

public static string RegexReplace(this string this, string pattern, string replacement, RegexOptions regexOption)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式
String	replacement	替换字符串
RegexOptions	regexOption	正则表达式选项

Returns

Type	Description
String

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RegexReplace(String, String, MatchEvaluator)

正则表达式 - 替换字符串

Declaration

public static string RegexReplace(this string this, string pattern, MatchEvaluator evaluator)

Parameters

Type	Name	Description
String	this	源字符串
String	pattern	正则表达式
MatchEvaluator	evaluator	委托表示的方法返回的字符串

Returns

Type	Description
String

Examples

var rs2 = test1.RegexReplace(@"\.", match => match.Value + "@");  // "aaaa.@bbbb.@cccc"

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
RegexMatchTimeoutException

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RegexSplit(String, String)

正则表达式 - 拆分字符串

使用 None

Declaration

public static string[] RegexSplit(this string this, string pattern)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式

Returns

Type	Description
String[]

Examples

var str = "aaaa.bbbb.cccc";
var rs = str.RegexSplit(@"\."); // rs.Count == 3

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException
RegexMatchTimeoutException

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RegexSplit(String, String, RegexOptions)

正则表达式 - 拆分字符串

Declaration

public static string[] RegexSplit(this string this, string pattern, RegexOptions regexOption)

Parameters

Type	Name	Description
String	this
String	pattern	正则表达式
RegexOptions	regexOption	正则表达式选项

Returns

Type	Description
String[]

Examples

var str = "aaaa.bbbb.cccc";
var rs = str.RegexSplit(@"\."); // rs.Count == 3

Exceptions

Type	Condition
ArgumentException
ArgumentNullException
ArgumentOutOfRangeException
RegexMatchTimeoutException

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RemovePrefix(String, String, StringComparison)

移除前缀，若前缀不符则返回原字符串

默认不区分大小写

Declaration

public static string RemovePrefix(this string this, string prefix, StringComparison stringComparison = StringComparison.OrdinalIgnoreCase)

Parameters

Type	Name	Description
String	this
String	prefix	前缀
StringComparison	stringComparison

Returns

Type	Description
String

Examples

"t_table".RemovePrefix("T_");                                       // "table"
"t_table".RemovePrefix("T_", StringComparison.Ordinal);             // "t_table"
"t_table".RemovePrefix("aaaaaaaaaaa", StringComparison.Ordinal);    // "t_table"
"t_table".RemovePrefix("T_TABLE");                                  // ""

"t_table".RemovePrefix(null);           // throw ArgumentNullException 
default(string).RemovePrefix("ddd");    // throw ArgumentNullException

Exceptions

Type	Condition
ArgumentNullException	`this` 不允许为空
ArgumentNullException	`prefix` 不允许为空

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RemoveSuffix(String, String, StringComparison)

移除后缀，若后缀不符则返回原字符串

默认不区分大小写

Declaration

public static string RemoveSuffix(this string this, string suffix, StringComparison stringComparison = StringComparison.OrdinalIgnoreCase)

Parameters

Type	Name	Description
String	this
String	suffix	后缀
StringComparison	stringComparison

Returns

Type	Description
String

Examples

"logo.jpg".RemoveSuffix(".JPg");                            // "logo"
"logo.jpg".RemoveSuffix(".JPG", StringComparison.Ordinal);  // "logo.jpg"
"logo.jpg".RemoveSuffix("aaaaaaaa");                        // "logo.jpg"
"logo.jpg".RemoveSuffix("LoGO.jpG");                        // ""

"logo.jpg".RemoveSuffix(null);          // throw ArgumentNullException
default(string).RemoveSuffix("dddd");   // throw ArgumentNullException

Exceptions

Type	Condition
ArgumentNullException	`this` 不允许为空
ArgumentNullException	`suffix` 不允许为空

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Right(String, Int32)

从右侧返回指定长度的字符串

Declaration

public static string Right(this string this, int length)

Parameters

Type	Name	Description
String	this
Int32	length	指定长度不能小于 0

Returns

Type	Description
String

Examples

"1234567890".Right(3); // "890"

Exceptions

Type	Condition
ArgumentOutOfRangeException	`length` 不能小于 0

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ToBytes(String)

转换为 byte 数组

编码格式默认为 UTF8

Declaration

public static byte[] ToBytes(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
Byte[]

Examples

var source = "abcd";
var rs = source.ToBytes(Encoding.Unicode);
var rs2 = source.ToBytes();    // use Encoding.UTF8

Exceptions

Type	Condition
ArgumentNullException	`this` is null
EncoderFallbackException

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ToBytes(String, Encoding)

转换为 byte 数组

Declaration

public static byte[] ToBytes(this string this, Encoding encoding)

Parameters

Type	Name	Description
String	this
Encoding	encoding	编码格式

Returns

Type	Description
Byte[]

Examples

var source = "abcd";
var rs = source.ToBytes(Encoding.Unicode);
var rs2 = source.ToBytes();    // use Encoding.UTF8

Exceptions

Type	Condition
ArgumentNullException	`encoding` is null
ArgumentNullException	`this` is null
EncoderFallbackException

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ToXmlDocument(String)

转换为 XmlDocument

Declaration

public static XmlDocument ToXmlDocument(this string this)

Parameters

Type	Name	Description
String	this

Returns

Type	Description
XmlDocument

Examples

var source = "<item><name>wrench</name></item>";
var rs     = source.ToXmlDocument();

Exceptions

Type	Condition
XmlException