VB 有几个本机函数用于将 char 转换为 ASCII 值，反之亦然 - Asc() 和 Chr()。
现在我需要在 C# 中获得等效的功能。最好的方法是什么？
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96675 次
12 回答
31
您始终可以添加对 Microsoft.VisualBasic 的引用，然后使用完全相同的方法：Strings.Chr和Strings.Asc。
这是获得完全相同功能的最简单方法。
于 2009-04-06T12:37:59.340 回答
24
因为Asc()您可以将其char转换为int这样的：
int i = (int)your_char;
并且Chr()你可以char从一个int这样的转换回：
char c = (char)your_int;
这是一个演示整个事情的小程序：
using System;
class Program
{
static void Main()
{
char c = 'A';
int i = 65;
// both print "True"
Console.WriteLine(i == (int)c);
Console.WriteLine(c == (char)i);
}
}
于 2009-04-06T12:29:06.520 回答
6
我使用 resharper 得到了这些，确切的代码由 VB 在你的机器上运行
/// <summary>
/// Returns the character associated with the specified character code.
/// </summary>
///
/// <returns>
/// Returns the character associated with the specified character code.
/// </returns>
/// <param name="CharCode">Required. An Integer expression representing the <paramref name="code point"/>, or character code, for the character.</param><exception cref="T:System.ArgumentException"><paramref name="CharCode"/> < 0 or > 255 for Chr.</exception><filterpriority>1</filterpriority>
public static char Chr(int CharCode)
{
if (CharCode < (int) short.MinValue || CharCode > (int) ushort.MaxValue)
throw new ArgumentException(Utils.GetResourceString("Argument_RangeTwoBytes1", new string[1]
{
"CharCode"
}));
if (CharCode >= 0 && CharCode <= (int) sbyte.MaxValue)
return Convert.ToChar(CharCode);
try
{
Encoding encoding = Encoding.GetEncoding(Utils.GetLocaleCodePage());
if (encoding.IsSingleByte && (CharCode < 0 || CharCode > (int) byte.MaxValue))
throw ExceptionUtils.VbMakeException(5);
char[] chars = new char[2];
byte[] bytes = new byte[2];
Decoder decoder = encoding.GetDecoder();
if (CharCode >= 0 && CharCode <= (int) byte.MaxValue)
{
bytes[0] = checked ((byte) (CharCode & (int) byte.MaxValue));
decoder.GetChars(bytes, 0, 1, chars, 0);
}
else
{
bytes[0] = checked ((byte) ((CharCode & 65280) >> 8));
bytes[1] = checked ((byte) (CharCode & (int) byte.MaxValue));
decoder.GetChars(bytes, 0, 2, chars, 0);
}
return chars[0];
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// Returns an Integer value representing the character code corresponding to a character.
/// </summary>
///
/// <returns>
/// Returns an Integer value representing the character code corresponding to a character.
/// </returns>
/// <param name="String">Required. Any valid Char or String expression. If <paramref name="String"/> is a String expression, only the first character of the string is used for input. If <paramref name="String"/> is Nothing or contains no characters, an <see cref="T:System.ArgumentException"/> error occurs.</param><filterpriority>1</filterpriority>
public static int Asc(char String)
{
int num1 = Convert.ToInt32(String);
if (num1 < 128)
return num1;
try
{
Encoding fileIoEncoding = Utils.GetFileIOEncoding();
char[] chars = new char[1]
{
String
};
if (fileIoEncoding.IsSingleByte)
{
byte[] bytes = new byte[1];
fileIoEncoding.GetBytes(chars, 0, 1, bytes, 0);
return (int) bytes[0];
}
byte[] bytes1 = new byte[2];
if (fileIoEncoding.GetBytes(chars, 0, 1, bytes1, 0) == 1)
return (int) bytes1[0];
if (BitConverter.IsLittleEndian)
{
byte num2 = bytes1[0];
bytes1[0] = bytes1[1];
bytes1[1] = num2;
}
return (int) BitConverter.ToInt16(bytes1, 0);
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// Returns an Integer value representing the character code corresponding to a character.
/// </summary>
///
/// <returns>
/// Returns an Integer value representing the character code corresponding to a character.
/// </returns>
/// <param name="String">Required. Any valid Char or String expression. If <paramref name="String"/> is a String expression, only the first character of the string is used for input. If <paramref name="String"/> is Nothing or contains no characters, an <see cref="T:System.ArgumentException"/> error occurs.</param><filterpriority>1</filterpriority>
public static int Asc(string String)
{
if (String == null || String.Length == 0)
throw new ArgumentException(Utils.GetResourceString("Argument_LengthGTZero1", new string[1]
{
"String"
}));
return Strings.Asc(String[0]);
}
资源只是存储错误消息，因此您希望以某种方式忽略它们，而您无权访问的其他两种方法如下：
internal static Encoding GetFileIOEncoding()
{
return Encoding.Default;
}
internal static int GetLocaleCodePage()
{
return Thread.CurrentThread.CurrentCulture.TextInfo.ANSICodePage;
}
于 2016-05-03T09:12:56.163 回答
3
Strings.Asc 不等同于可以超出 127 代码值的非 ASCII 字符的普通 C# 转换。我在 https://social.msdn.microsoft.com/Forums/vstudio/en-US/13fec271-9a97-4b71-ab28-4911ff3ecca0/equivalent-in-c-of-asc-chr-functions-of上找到的答案-vb?forum=csharpgeneral 相当于这样的东西：
static int Asc(char c)
{
int converted = c;
if (converted >= 0x80)
{
byte[] buffer = new byte[2];
// if the resulting conversion is 1 byte in length, just use the value
if (System.Text.Encoding.Default.GetBytes(new char[] { c }, 0, 1, buffer, 0) == 1)
{
converted = buffer[0];
}
else
{
// byte swap bytes 1 and 2;
converted = buffer[0] << 16 | buffer[1];
}
}
return converted;
}
或者，如果您想要读取交易，请添加对 Microsoft.VisualBasic 程序集的引用。
于 2016-01-21T22:30:43.247 回答
1
对于 Chr()，您可以使用：
char chr = (char)you_char_value;
于 2009-04-06T12:30:39.560 回答
1
在 C# 中，您可以使用 Char.ConvertFromUtf32 语句
int intValue = 65; \\ Letter A
string strVal = Char.ConvertFromUtf32(intValue);
相当于VB的
Dim intValue as integer = 65
Dim strValue As String = Char.ConvertFromUtf32(intValue)
无需 Microsoft.VisualBasic 参考
于 2018-12-13T18:17:59.733 回答
0
将此方法添加到 C# 中
private int Asc(char String)
{
int int32 = Convert.ToInt32(String);
if (int32 < 128)
return int32;
try
{
Encoding fileIoEncoding = Encoding.Default;
char[] chars = new char[1] { String };
if (fileIoEncoding.IsSingleByte)
{
byte[] bytes = new byte[1];
fileIoEncoding.GetBytes(chars, 0, 1, bytes, 0);
return (int)bytes[0];
}
byte[] bytes1 = new byte[2];
if (fileIoEncoding.GetBytes(chars, 0, 1, bytes1, 0) == 1)
return (int)bytes1[0];
if (BitConverter.IsLittleEndian)
{
byte num = bytes1[0];
bytes1[0] = bytes1[1];
bytes1[1] = num;
}
return (int)BitConverter.ToInt16(bytes1, 0);
}
catch (Exception ex)
{
throw ex;
}
}
`
于 2019-01-24T09:51:31.363 回答
0
我从 Microsoft.VisualBasic.dll 中提取了 Asc() 函数：
public static int Asc(char String)
{
int num;
byte[] numArray;
int num1 = Convert.ToInt32(String);
if (num1 >= 128)
{
try
{
Encoding fileIOEncoding = Encoding.Default;
char[] str = new char[] { String };
if (!fileIOEncoding.IsSingleByte)
{
numArray = new byte[2];
if (fileIOEncoding.GetBytes(str, 0, 1, numArray, 0) != 1)
{
if (BitConverter.IsLittleEndian)
{
byte num2 = numArray[0];
numArray[0] = numArray[1];
numArray[1] = num2;
}
num = BitConverter.ToInt16(numArray, 0);
}
else
{
num = numArray[0];
}
}
else
{
numArray = new byte[1];
fileIOEncoding.GetBytes(str, 0, 1, numArray, 0);
num = numArray[0];
}
}
catch (Exception exception)
{
throw exception;
}
}
else
{
num = num1;
}
return num;
}
于 2019-08-13T09:40:19.330 回答
0
于 2019-08-28T18:54:29.173 回答
0
以下例程适用于 .net 标准 2.0 + .net 5 的 COM 互操作服务器环境和经典 ASP/VB6 客户端，代码页为 1252。
我没有用其他代码页测试它：
public static int Asc(char String)
{
int int32 = Convert.ToInt32(String);
if (int32 < 128)
return int32;
Encoding encoding = CodePagesEncodingProvider.Instance.GetEncoding(Thread.CurrentThread.CurrentCulture.TextInfo.ANSICodePage);
char[] chars = new char[1] { String };
if (encoding.IsSingleByte)
{
byte[] bytes = new byte[1];
encoding.GetBytes(chars, 0, 1, bytes, 0);
return (int)bytes[0];
}
byte[] bytes1 = new byte[2];
if (encoding.GetBytes(chars, 0, 1, bytes1, 0) == 1)
return (int)bytes1[0];
if (BitConverter.IsLittleEndian)
{
byte num = bytes1[0];
bytes1[0] = bytes1[1];
bytes1[1] = num;
}
return (int)BitConverter.ToInt16(bytes1, 0);
}
于 2021-06-03T12:02:43.627 回答
-1
//Char to Int - ASC("]")
int lIntAsc = (int)Char.Parse("]");
Console.WriteLine(lIntAsc); //Return 91
//Int to Char
char lChrChar = (char)91;
Console.WriteLine(lChrChar ); //Return "]"
于 2018-02-23T13:59:53.747 回答
-2
给定 char c 和 int i，以及函数 fi(int) 和 fc(char)：
从 char 到 int（类似于 VB Asc()）：将 char 显式转换为 int：int i = (int)c;
或隐式转换（提升）：fi(char c) {i+= c;}
从 int 到 char（类似于 VB Chr()）：
将 int 显式转换为 char：char c = (char)i, fc(int i) {(char)i};
不允许隐式转换，因为 int 比 char 更宽（具有更大的值范围）
于 2009-04-06T12:35:11.250 回答