Question

我正在尝试创建一个模板方法，通过二进制读取器从文件中读取float或double值。

我不能使用Binaryreader.readSingle或Binaryreader.readDouble方法，因为它们太具体了......可能是读取字节并使用bitConverter转换为float或double。但bitConverter可以将字节转换为模板类型“T”吗？

// Note: T type will be either float or double 
static void readValues<T>(string fileName, T[] arr, int arrLen)
{
   BinaryReader reader = new BinaryReader(File.Open(fileName, FileMode.Open));

   for(int i = 0; i < arrLen; i++)
   {
      // Have to use one of the methods to read the values
      // which one to use

      // 1. To read float
      //arr[i] = reader.readSingle();

      // 2. To read Double
      //arr[i] = reader.readDouble();


   }
}

Answer 1

像往常一些人（我）仍然关注某些乐器......如果你所拥有的只是一把锤子，你所有的问题都会像钉子一样......没有使用表达树（如果有人有兴趣，那么另一个版本）表达树是历史的一部分）。一个类根据泛型类型T将委托缓存到“右”方法。另一个类使一切都作为扩展方法工作。

public static class BinaryReaderEx
{
    public static T Read<T>(this BinaryReader br)
    {
        return BinaryReader<T>.Read(br);
    }
}

public static class BinaryReader<T>
{
    public static readonly Func<BinaryReader, T> Read;

    static BinaryReader()
    {
        Type type = typeof(T);

        if (type == typeof(bool))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, bool>)(p => p.ReadBoolean()));
        }
        else if (type == typeof(char))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, char>)(p => p.ReadChar()));
        }
        else if (type == typeof(string))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, string>)(p => p.ReadString()));
        }
        else if (type == typeof(sbyte))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, sbyte>)(p => p.ReadSByte()));
        }
        else if (type == typeof(short))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, short>)(p => p.ReadInt16()));
        }
        else if (type == typeof(int))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, int>)(p => p.ReadInt32()));
        }
        else if (type == typeof(long))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, long>)(p => p.ReadInt64()));
        }
        else if (type == typeof(byte))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, byte>)(p => p.ReadByte()));
        }
        else if (type == typeof(ushort))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, ushort>)(p => p.ReadUInt16()));
        }
        else if (type == typeof(uint))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, uint>)(p => p.ReadUInt32()));
        }
        else if (type == typeof(ulong))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, ulong>)(p => p.ReadUInt64()));
        }
        else if (type == typeof(float))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, float>)(p => p.ReadSingle()));
        }
        else if (type == typeof(double))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, double>)(p => p.ReadDouble()));
        }
        else if (type == typeof(decimal))
        {
            Read = (Func<BinaryReader, T>)(Delegate)((Func<BinaryReader, decimal>)(p => p.ReadDecimal()));
        }
        else
        {
            throw new ArgumentException();
        }
    }
}

使用：

using (var br = new BinaryReader(ms))
{
    //byte b = BinaryReader<bool>.Read(br);
    //double d = BinaryReader<double>.Read(br);
    //string s = BinaryReader<string>.Read(br);

    // Or

    byte b = br.Read<bool>();
    double d = br.Read<double>();
    string s = br.Read<string>();
}

Answer 2

这不是一个好的情况，仿制药将是一个很好的设计选择。

编写两个函数会更好，一个函数接受一个双精度数组，另一个函数接受一个浮点数组。编译器将根据您传入的数组选择正确的重载，并且在您抛出所有错误处理（如果我传入一组int中的内容？）和cast而不是泛型版本后，它甚至可能最终会减少代码。

bitconverter可以将字节转换为模板类型“T”吗？

2 个答案: