字符串总长度为5个字符
我有一个场景,ID以A0001开头,以A9999结尾,然后是B0001到B9999,直到F0001到F9999
之后
从FA001到FA999,然后是FB001到FB999,一直到....FFFF9
请建议如何创建这种格式。
public static IEnumerable<string> Numbers()
{
return Enumerable.Range(0xA0000, 0xFFFF9 - 0xA0000 + 1)
.Select(x => x.ToString("X"));
}
public class IdGenerator
{
private const int Min = 0xA0000;
private const int Max = 0xFFFF9;
private int _value = Min - 1;
public string NextId()
{
if (_value < Max)
{
_value++;
}
else
{
_value = Min;
}
return _value.ToString("X");
}
}
虽然我晚了几年,但我希望我的答案能够帮助需要好的ID生成器的人。之前的回答都不能按照预期工作,也没有回答这个问题。
我的答案完全符合要求,而且更好!!!
请注意,将_fixedLength设置为零将创建动态大小的ID。将其设置为其他值将创建固定长度的ID;
还请注意,调用使用当前ID的重载将“播种”该类,并且连续调用不需要使用另一个ID进行调用。除非您有随机ID并需要每次获取下一个ID。
享受吧!
public static class IDGenerator
{
private static readonly char _minChar = 'A';
private static readonly char _maxChar = 'C';
private static readonly int _minDigit = 1;
private static readonly int _maxDigit = 5;
private static int _fixedLength = 5;//zero means variable length
private static int _currentDigit = 1;
private static string _currentBase = "A";
public static string NextID()
{
if(_currentBase[_currentBase.Length - 1] <= _maxChar)
{
if(_currentDigit <= _maxDigit)
{
var result = string.Empty;
if(_fixedLength > 0)
{
var prefixZeroCount = _fixedLength - _currentBase.Length;
if(prefixZeroCount < _currentDigit.ToString().Length)
throw new InvalidOperationException("The maximum length possible has been exeeded.");
result = result = _currentBase + _currentDigit.ToString("D" + prefixZeroCount.ToString());
}
else
{
result = _currentBase + _currentDigit.ToString();
}
_currentDigit++;
return result;
}
else
{
_currentDigit = _minDigit;
if(_currentBase[_currentBase.Length - 1] == _maxChar)
{
_currentBase = _currentBase.Remove(_currentBase.Length - 1) + _minChar;
_currentBase += _minChar.ToString();
}
else
{
var newChar = _currentBase[_currentBase.Length - 1];
newChar++;
_currentBase = _currentBase.Remove(_currentBase.Length - 1) + newChar.ToString();
}
return NextID();
}
}
else
{
_currentDigit = _minDigit;
_currentBase += _minChar.ToString();
return NextID();
}
}
public static string NextID(string currentId)
{
if(string.IsNullOrWhiteSpace(currentId))
return NextID();
var charCount = currentId.Length;
var indexFound = -1;
for(int i = 0; i < charCount; i++)
{
if(!char.IsNumber(currentId[i]))
continue;
indexFound = i;
break;
}
if(indexFound > -1)
{
_currentBase = currentId.Substring(0, indexFound);
_currentDigit = int.Parse(currentId.Substring(indexFound)) + 1;
}
return NextID();
}
}
下面是使用 _fixedLength = 4 和 _maxDigit = 5 的输出示例:
A001 A002 A003 A004 A005 B001 B002 B003 B004 B005 C001 C002 C003 C004 C005 AA01 AA02 AA03 AA04 AA05 AB01 AB02 AB03 AB04 AB05 AC01 AC02 AC03 AC04 AC05
private void button1_Click(object sender, EventArgs e)
{
string get = label1.Text.Substring(7); //label1.text=ATHCUS-100
MessageBox.Show(get);
string ou="ATHCUS-"+(Convert.ToInt32(get)+1).ToString();
label1.Text = ou.ToString();
}
SELECT TOP 1 [ID_COLUMN] FROM [NAME_OF_TABLE] ORDER BY [ID_COLUMN] DESC
public string NextID(string lastID)
{
var allLetters = new string[] {"A", "B", "C", "D", "E", "F"};
var lastLetter = lastID.Substring(0, 1);
var lastNumber = int.Parse(lastID.Substring(1));
if (Array.IndexOf(allLetters, lastLetter) < allLetters.Length - 1 &&
lastNumber == 9999)
{
//increase the letter
lastLetter = allLetters(Array.IndexOf(allLetters, lastLetter) + 1);
lastNumber = 0;
} else {
lastLetter = "!";
}
var result = lastLetter + (lastNumber + 1).ToString("0000");
//ensure we haven't exceeded the upper limit
if (result.SubString(0, 1) == "!") {
result = "Upper Bounds Exceeded!";
}
return result;
}
免责声明
此代码仅生成第一组ID。我不理解生成第二组的过程。
int dbid = /* get id from db */
string id = dbid.ToString("X5");
这应该可以为您提供所需的格式,作为从数据库ID直接转换的结果。