获得图片的真实格式

csharp

http://www.chenjiliang.com/Article/View.aspx?id=320

public bool IsPicture(string filePath)//filePath是文件的完整路径
{
    try
    {
        FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
        BinaryReader reader = new BinaryReader(fs);
        string fileClass;
        byte buffer;
        byte[] b = new byte[2];
        buffer = reader.ReadByte();
        b[0] = buffer;
        fileClass = buffer.ToString();
        buffer = reader.ReadByte();
        b[1] = buffer;
        fileClass += buffer.ToString();
        reader.Close();
        fs.Close();
        if (fileClass == "255216" || fileClass == "7173" || fileClass == "13780")//255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    catch
    {
        return false;
    }
}

csharp

/// <summary>
/// 返回图片格式（和文件名后缀无关）
/// </summary>
/// <param name="strImgPath">图片路径及名称</param>
/// <returns>jpeg\gif\bmp\png\tif\icon\wmf</returns>
string GetImageFormat(string strImgFilePath)
{
    string strImgFormat = "";
    System.Drawing.Image imgSrc = System.Drawing.Image.FromFile(strImgFilePath);
    if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Jpeg))
        strImgFormat = "jpeg";
    else if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Gif))
        strImgFormat = "gif";
    else if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Bmp))
        strImgFormat = "bmp";
    else if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Png))
        strImgFormat = "png";
    else if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Tiff))
        strImgFormat = "tiff";
    else if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Icon))
        strImgFormat = "icon";
    else if (imgSrc.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Wmf))
        strImgFormat = "wmf";
    return strImgFormat;
}