给你:

private Stream GenerateStreamFromString(String p)
{
    Byte[] bytes = UTF8Encoding.GetBytes(p);
    MemoryStream strm = new MemoryStream();
    strm.Write(bytes, 0, bytes.Length);
    return strm;
}

使用MemoryStream类，调用Encoding。GetBytes首先将字符串转换为字节数组。

您随后是否需要流上的TextReader ?如果是这样，您可以直接提供一个StringReader，并绕过MemoryStream和Encoding步骤。

public Stream GenerateStreamFromString(string s)
{
    return new MemoryStream(Encoding.UTF8.GetBytes(s));
}

我认为您可以从使用MemoryStream中受益。您可以使用使用Encoding类的GetBytes方法获得的字符串字节填充它。

给你:

private Stream GenerateStreamFromString(String p)
{
    Byte[] bytes = UTF8Encoding.GetBytes(p);
    MemoryStream strm = new MemoryStream();
    strm.Write(bytes, 0, bytes.Length);
    return strm;
}

如果你需要改变编码，我投票给@ShaunBowe的解决方案。但是这里的每个答案都至少将整个字符串复制到内存中一次。ToCharArray + BlockCopy组合的答案做了两次。

如果这很重要的话，这里有一个用于原始UTF-16字符串的简单流包装器。如果与StreamReader一起使用，请选择Encoding。Unicode:

public class StringStream : Stream
{
    private readonly string str;

    public override bool CanRead => true;
    public override bool CanSeek => true;
    public override bool CanWrite => false;
    public override long Length => str.Length * 2;
    public override long Position { get; set; } // TODO: bounds check

    public StringStream(string s) => str = s ?? throw new ArgumentNullException(nameof(s));

    public override long Seek(long offset, SeekOrigin origin)
    {
        switch (origin)
        {
            case SeekOrigin.Begin:
                Position = offset;
                break;
            case SeekOrigin.Current:
                Position += offset;
                break;
            case SeekOrigin.End:
                Position = Length - offset;
                break;
        }

        return Position;
    }

    private byte this[int i] => (i & 1) == 0 ? (byte)(str[i / 2] & 0xFF) : (byte)(str[i / 2] >> 8);

    public override int Read(byte[] buffer, int offset, int count)
    {
        // TODO: bounds check
        var len = Math.Min(count, Length - Position);
        for (int i = 0; i < len; i++)
            buffer[offset++] = this[(int)(Position++)];
        return (int)len;
    }

    public override int ReadByte() => Position >= Length ? -1 : this[(int)Position++];
    public override void Flush() { }
    public override void SetLength(long value) => throw new NotSupportedException();
    public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
    public override string ToString() => str; // ;)     
}

这里有一个更完整的解决方案，包含必要的绑定检查(派生自MemoryStream，因此它也有ToArray和WriteTo方法)。