vb.net 中的 Strings类全部字符串操作的所有函数及其功能和详细代码每行上面注释

在 VB.NET 中，Strings 类提供了许多用于字符串操作的函数，以下是其中所有常用函数及其功能和详细代码：

1. Asc(string) As Integer

功能：返回字符串第一个字符的 ASCII 码值。

详细代码：

Dim str As String = "hello world"
Dim ascii As Integer = Asc(str) ' 获取字符串第一个字符的 ASCII 码值

2. Chr(charCode As Integer) As Char

功能：根据指定的 ASCII 码值返回字符。

详细代码：

Dim charCode As Integer = 65
Dim ch As Char = Chr(charCode) ' 获取 ASCII 码值为 65 的字符 'A'

3. Len(str As String) As Integer

功能：返回字符串的长度。

详细代码：

Dim str As String = "hello world"
Dim len As Integer = Len(str) ' 获取字符串长度

4. Mid(str As String, start As Integer, [length As Integer]) As String

功能：返回从指定位置开始的指定长度的子字符串。

详细代码：

Dim str As String = "hello world"
Dim subStr As String = Mid(str, 1, 5) ' 获取从字符串第一个字符开始的前5个字符

5. InStr([start As Integer, ]string1 As String, string2 As String[, compare As CompareMethod = CompareMethod.Binary]) As Integer

功能：返回一个字符串在另一个字符串中第一次出现的位置。

详细代码：

Dim str As String = "hello world"
Dim index As Integer = InStr(str, "world") ' 获取子字符串 "world" 在原字符串中的位置

6. Replace(expression As String, find As String, replacement As String[, start As Integer = 1[, count As Integer = -1[, compare As CompareMethod = CompareMethod.Binary]]]) As String

功能：替换字符串中指定的子字符串。

详细代码：

Dim str As String = "hello world"
Dim newStr As String = Replace(str, "world", "vb.net") ' 将子字符串 "world" 替换为 "vb.net"

7. Trim([string]) As String

功能：去除字符串两端的空格。

详细代码：

Dim str As String = " hello world "
Dim newStr As String = Trim(str) ' 去除字符串两端的空格

8. LCase(string) As String

功能：将字符串转换为小写。

详细代码：

Dim str As String = "Hello World"
Dim newStr As String = LCase(str) ' 将字符串转换为小写

9. UCase(string) As String

功能：将字符串转换为大写。

详细代码：

Dim str As String = "Hello World"
Dim newStr As String = UCase(str) ' 将字符串转换为大写

10. Str(str As Object) As String

功能：将数字或其他数据类型转换为字符串。

详细代码：

Dim num As Integer = 123
Dim str As String = Str(num) ' 将数字 123 转换为字符串

11. String(number As Integer, [character As Char]) As String

功能：创建一个指定长度的字符串，并用指定的字符填充。

详细代码：

Dim str As String = String(5, "x"c) ' 创建一个长度为 5 的字符串，用字符 'x' 填充

12. Left(str As String, length As Integer) As String

功能：返回字符串的左侧指定长度的子字符串。

详细代码：

Dim str As String = "hello world"
Dim subStr As String = Left(str, 5) ' 获取字符串左侧的前5个字符

13. Right(str As String, length As Integer) As String

功能：返回字符串的右侧指定长度的子字符串。

详细代码：

Dim str As String = "hello world"
Dim subStr As String = Right(str, 5) ' 获取字符串右侧的后5个字符

14. Space(number As Integer) As String

功能：创建一个指定长度的空格字符串。

详细代码：

Dim str As String = Space(5) ' 创建一个长度为 5 的空格字符串

15. Split(expression As String[, delimiter As String = " "[, limit As Integer = -1[, compare As CompareMethod = CompareMethod.Binary]]]) As String()

功能：将字符串按指定分隔符分割成字符串数组。

详细代码：

Dim str As String = "hello,world,vb.net"
Dim arr() As String = Split(str, ",") ' 将字符串按逗号分隔成字符串数组

16. Join(stringArray() As String[, delimiter As String = ""]) As String

功能：将字符串数组按指定分隔符连接成一个字符串。

详细代码：

Dim arr() As String = {"hello", "world", "vb.net"}
Dim str As String = Join(arr, ",") ' 将字符串数组按逗号连接成一个字符串

17. StrComp(string1 As String, string2 As String[, compare As CompareMethod = CompareMethod.Binary]) As Integer

功能：比较两个字符串的大小关系。

详细代码：

Dim str1 As String = "hello"
Dim str2 As String = "world"
Dim result As Integer = StrComp(str1, str2) ' 比较字符串 str1 和字符串 str2 的大小关系

18. StrReverse(string) As String

功能：将字符串反转。

详细代码：

Dim str As String = "hello world"
Dim newStr As String = StrReverse(str) ' 将字符串反转