通用的编码格式为UTF8 ，你也可以修改codingType类型获取想要的编码格式的结果

using UnityEngine.UI;
using System;
using UnityEngine;

/// <summary>
/// 编码类型
/// </summary>
public enum CodingType
{
    UTF8 = 1,
    ASCII,
    Unicode,
    GB,
}
public class CheckCodingFormat : MonoBehaviour
{
    /// <summary>
    /// 编辑结束回调
    /// </summary>
    /// <param name="content"></param>
    public delegate void CallBackInputContent(string content);
    public event CallBackInputContent onChangeValueCallBack;
    public event CallBackInputContent onEndEditCallBack;

    /// <summary>
    /// 限制的字节数
    /// </summary>
    public int BYTE_LIMIT = 10;

    public CodingType codingType = CodingType.UTF8;
    private InputField inputField;
    void Awake()
    {
        inputField = transform.GetComponent<InputField>();
        inputField.onEndEdit.AddListener(OnEndEdit);
    }

  /// <summary>
    /// 实时改变内容时的回调
    /// </summary>
    /// <param name="value"></param>
    private void OnChangedValue(string value)
    {
        value = GetCodingResult(codingType);
        inputField.text = value;
        if (onChangeValueCallBack != null)
        {
            onChangeValueCallBack(value);
        }
    }

    /// <summary>
    /// 结束编辑后的回调
    /// </summary>
    /// <param name="value"></param>
    private void OnEndEdit(string value)
    {
        value = GetCodingResult(codingType);
        inputField.text = value;
        if (onEndEditCallBack != null)
        {
            onEndEditCallBack(value);
        }
    }

    /// <summary>
    /// 获取编码结果
    /// </summary>
    /// <param name="checkType"></param>
    /// <returns></returns>
    public string GetCodingResult(CodingType checkType)
    {
        string value = "";
        string temp = inputField.text.Substring(0, (inputField.text.Length < BYTE_LIMIT + 1) ? inputField.text.Length : BYTE_LIMIT + 1);
        switch (checkType)
        {
            case CodingType.UTF8:
                value = CodingByUTF8(temp);
                break;
            case CodingType.ASCII:
                value = CodingByASCII(temp);
                break;
            case CodingType.Unicode:
                value = CodingByUnicode(temp);
                break;
            case CodingType.GB:
                value = CodingByGB(temp);
                break;
        }
        return value;
    }

    /// <summary>
    /// UTF8编码格式
    /// </summary>
    /// <param name="temp"></param>
    /// <returns></returns>
    private string CodingByUTF8(string temp)
    {
        string outputStr = "";
        int count = 0;
        for (int i = 0; i < temp.Length; i++)
        {
            string tempStr = temp.Substring(i, 1);
            byte[] encodedBytes = System.Text.ASCIIEncoding.UTF8.GetBytes(tempStr);
            string output = "[" + temp + "]";
            for (int byteIndex = 0; byteIndex < encodedBytes.Length; byteIndex++)
            {
                output += Convert.ToString((int)encodedBytes[byteIndex], 2) + "  ";
            }
            int byteCount = System.Text.ASCIIEncoding.UTF8.GetByteCount(tempStr);
            // 中文2字节，英文1字节
            count = byteCount > 1 ? count += 2 : count += 1;
            if (count <= BYTE_LIMIT)
                outputStr += tempStr;
            else
                break;
        }
        return outputStr;
    }

    /// <summary>
    /// Unicode 编码格式
    /// </summary>
    /// <param name="temp"></param>
    /// <returns></returns>
    private string CodingByUnicode(string temp)
    {
        string outputStr = "";
        int count = 0;

        for (int i = 0; i < temp.Length; i++)
        {
            string tempStr = temp.Substring(i, 1);
            // Unicode用两个字节对字符进行编码
            byte[] encodedBytes = System.Text.ASCIIEncoding.Unicode.GetBytes(tempStr);
            if (encodedBytes.Length == 2)
            {
                int byteValue = (int)encodedBytes[1];
                if (byteValue == 0)//这里是单个字节
                {
                    count += 1;
                }
                else
                {
                    count += 2;
                }
            }
            if (count <= BYTE_LIMIT)
            {
                outputStr += tempStr;
            }
            else
            {
                break;
            }
        }
        return outputStr;
    }

    /// <summary>
    /// GB编码格式
    /// </summary>
    /// <param name="temp"></param>
    /// <returns></returns>
    private string CodingByGB(string temp)
    {
        string outputStr = "";
        int count = 0;
        for (int i = 0; i < temp.Length; i++)
        {
            string tempStr = temp.Substring(i, 1);
            byte[] encodedBytes = System.Text.ASCIIEncoding.Default.GetBytes(tempStr);
            if (encodedBytes.Length == 1)
            {
                count += 1;
            }
            else
            {
                count += 2;
            }
            if (count <= BYTE_LIMIT)
            {
                outputStr += tempStr;
            }
            else
            {
                break;
            }
        }
        return outputStr;
    }

    /// <summary>
    /// ASCII编码格式
    /// </summary>
    /// <param name="temp"></param>
    /// <returns></returns>
    private string CodingByASCII(string temp)
    {
        byte[] encodedBytes = System.Text.ASCIIEncoding.ASCII.GetBytes(temp);
        string outputStr = "";
        int count = 0;
        for (int i = 0; i < temp.Length; i++)
        {
            if ((int)encodedBytes[i] == 63)
                count += 2;
            else
                count += 1;
            if (count <= BYTE_LIMIT)
                outputStr += temp.Substring(i, 1);
            else if (count > BYTE_LIMIT)
                break;
        }
        if (count <= BYTE_LIMIT)
        {
            outputStr = temp;
        }
        return outputStr;
    }
}

// 字符串所占字节长度
    public static int CharacterLength(string content)
    {
        content = content.Replace('?', 'a');
        byte[] _byteArray = System.Text.Encoding.ASCII.GetBytes(content);
        int _count = 0;
        for (int i = 0; i < _byteArray.Length; ++i)
        {
//未在ASCII码表上的字符转化为 ? - 63
            if (63 == _byteArray[i])
            {
                _count += 2;
            }
            else
            {
                _count++;
            }
        }
        return _count;
    }