C#读取中文文件出现乱码的解决方法

FileStream aFile = new FileStream(SingleFile,FileMode.Open);
StreamReader sr = new StreamReader(aFile,Encoding.GetEncoding("gb2312"),true);
string FileContent = sr.ReadToEnd();
aFile.Close();
ProcessData Pd = new ProcessData();
Pd.ProceData(FileContent);

private void DetectEncoding()
{
 if (this.byteLen >= 2)
 {
 this._detectEncoding = false;
 bool flag = false;
 if ((this.byteBuffer[0] == 0xfe) && (this.byteBuffer[1] == 0xff))
 {
  this.encoding = new UnicodeEncoding(true, true);
  this.CompressBuffer(2);
  flag = true;
 }
 else if ((this.byteBuffer[0] == 0xff) && (this.byteBuffer[1] == 0xfe))
 {
  if (((this.byteLen < 4) || (this.byteBuffer[2] != 0)) || (this.byteBuffer[3] != 0))
  {
 this.encoding = new UnicodeEncoding(false, true);
 this.CompressBuffer(2);
 flag = true;
  }
  else
  {
 this.encoding = new UTF32Encoding(false, true);
 this.CompressBuffer(4);
 flag = true;
  }
 }
 else if (((this.byteLen >= 3) && (this.byteBuffer[0] == 0xef)) && ((this.byteBuffer[1] == 0xbb) && (this.byteBuffer[2] == 0xbf)))
 {
  this.encoding = Encoding.UTF8;
  this.CompressBuffer(3);
  flag = true;
 }
 else if ((((this.byteLen >= 4) && (this.byteBuffer[0] == 0)) && ((this.byteBuffer[1] == 0) && (this.byteBuffer[2] == 0xfe))) && (this.byteBuffer[3] == 0xff))
 {
  this.encoding = new UTF32Encoding(true, true);
  this.CompressBuffer(4);
  flag = true;
 }
 else if (this.byteLen == 2)
 {
  this._detectEncoding = true;
 }
 if (flag)
 {
  this.decoder = this.encoding.GetDecoder();
  this._maxCharsPerBuffer = this.encoding.GetMaxCharCount(this.byteBuffer.Length);
  this.charBuffer = new char[this._maxCharsPerBuffer];
 }
 }
}