为了更好.NET内置多种方法可用于文件读取,文件流FileStream,文本流StreamReader,二进制读取BinaryReader
File.OpenRead

File.OpenText
public string ReadFile(string fileOpenPath)
{
if (!System.IO.File.Exists(fileOpenPath))
{
return null;
}
using (System.IO.StreamReader sr = System.IO.File.OpenText(fileOpenPath))
{
return sr.ReadToEnd().ToString();
}
}