C#中用到的知识点－小笔记

struct FileFormat
{
    public string prefix;
    public string suffix;
    public int numberLength;
    public int startNumber;
    public int endNumber;
}
public class FileReader{
    StreamReader sr;
    string txtFileName = "picture list.txt";
    string texturePath;

    public int textureLength { get; private set; }
    private List<FileFormat> _textureInfo;

	// Use this for initialization
	public void Start () 
    {
        // initial variable
        _textureInfo = new List<FileFormat>();
        // open exist .txt file
        if (File.Exists(txtFileName) && txtFileName != null)
        {
            sr = new StreamReader("picture list.txt");
            DecodeTxtFile();
        }
	}

    /// <summary>
    /// decode the txt file     1.前缀 2.后缀 3.内容长度 4.开始数字 5.结束数字
    /// </summary>
    /// 
    private void DecodeTxtFile()
    {
        while (true)
        {
            string sLine = sr.ReadLine();
            if (sLine != null)
            {
                // the first line is the path
                if (texturePath == null)
                {
                    texturePath = sLine;
                }
                else
                {
                    char[] delimiters = { ‘ ‘ };
                    string[] sLineParts = sLine.Split(delimiters);

                    if (sLineParts.Length >= 5)
                    {
                        FileFormat ff = new FileFormat();
                        ff.prefix = sLineParts[0];
                        ff.suffix = sLineParts[1];
                        int.TryParse(sLineParts[2], out ff.numberLength);
                        int.TryParse(sLineParts[3], out ff.startNumber);
                        int.TryParse(sLineParts[4], out ff.endNumber);
                        _textureInfo.Add(ff);
                    }
                }
            }
            else
                break; 
        }

        textureLength = _textureInfo.Count;
    }

    /// <summary>
    /// get the texture length by the texture infor index
    /// </summary>
    /// <param name="index"></param>
    /// <returns></returns>
    public int GetLengthByIndex(int index)
    {
        if (index <= textureLength && index >= 0)
        {
            int lengthResult = _textureInfo[index].endNumber - _textureInfo[index].startNumber;
            return lengthResult;
        }
        return 0;
    }

    /// <summary>
    ///  get the string name of the texture file by index and texture number 
    /// </summary>
    /// <param name="index"></param>
    /// <param name="textureNumber"></param>
    /// <returns></returns>
    public string GetFileNameByIndex(int index, int textureNumber, bool attachedPath = false)
    {
        string sResult = "";
        if (textureNumber <= _textureInfo[index].endNumber - _textureInfo[index].startNumber)
        {
            if(!attachedPath)
                sResult = _textureInfo[index].prefix + string.Format("{0:D5}", _textureInfo[index].startNumber + textureNumber) + _textureInfo[index].suffix;
            else
                sResult = texturePath + "\\" + _textureInfo[index].prefix + string.Format("{0:D5}", _textureInfo[index].startNumber + textureNumber) + _textureInfo[index].suffix;
            return sResult;
        }
        return sResult;        
    }
}

    private FileInfo fileInfo;
    private byte[] imageData;

    /// <summary>
    /// decoder the image according to the filepath
    /// </summary>
    /// <param name="filePath"></param>
    public void Decoder(string filePath, out byte[] outImage)
    {
        if (filePath == null)
        {
            outImage = imageData;
            return;
        }
            
        fileInfo = new FileInfo(filePath);

        imageData = new byte[fileInfo.Length];

        using (FileStream fs = fileInfo.OpenRead())
        {
            fs.Read(imageData, 0, imageData.Length);
            outImage = imageData;
        }
    }

// texture to display the image
    private Texture2D tex;
    Decoder(fileName, out imageData);
    tex.LoadImage(imageData);