[开发笔记]-C#判断文件类型

亦凉 2021-04-24 03:03 928阅读 0赞

判断文件真实的类型，不是通过扩展名来判断：
````
    /// <summary>
            /// 判断文件格式
            /// http://www.dandelioncloud.cn/babycool 
            /// </summary>
            /// <param name="filePath"></param>
            /// <returns></returns>
            public static bool IsAllowedExtension(string filePath)
            {
    
                FileStream stream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
                BinaryReader reader = new BinaryReader(stream);
                string fileclass = "";
               // byte buffer;
                try
                {
                    
                    //buffer = reader.ReadByte();
                    //fileclass = buffer.ToString();
                    //buffer = reader.ReadByte();
                    //fileclass += buffer.ToString();
    
                    for (int i = 0; i < 2; i++)
                    {
                        fileclass += reader.ReadByte().ToString();
                    }
    
                }
                catch (Exception)
                {
    
                    throw;
                }
    
                if (fileclass == "255216")
                {
                    return true;
                }
                else
                {
                    return false;
                }
    
                /*文件扩展名说明
                 * 255216 jpg
                 * 208207 doc xls ppt wps
                 * 8075 docx pptx xlsx zip
                 * 5150 txt
                 * 8297 rar
                 * 7790 exe
                 * 3780 pdf      
                 * 
                 * 4946/104116 txt
                 * 7173        gif 
                 * 255216      jpg
                 * 13780       png
                 * 6677        bmp
                 * 239187      txt,aspx,asp,sql
                 * 208207      xls.doc.ppt
                 * 6063        xml
                 * 6033        htm,html
                 * 4742        js
                 * 8075        xlsx,zip,pptx,mmap,zip
                 * 8297        rar   
                 * 01          accdb,mdb
                 * 7790        exe,dll
                 * 5666        psd 
                 * 255254      rdp 
                 * 10056       bt种子 
                 * 64101       bat 
                 * 4059        sgf    
                 */
    
            }
````