将byte []字符串转换回byte []数组

Question

I have one scenario with class like this.

Class Document
{
    public string Name {get;set;}
    public byte[] Contents {get;set;}
}

Now I am trying to implement the import export functionality where I keep the document in binary so the document will be in json file with other fields and the document will be something in this format.

UEsDBBQABgAIAAAAIQCitGbRsgEAALEHAAATAAgCW0NvbnRlbnRfVHlwZXNdLnhtbCCiBAIooAACAAAAAAA==

Now when I upload this file back, I get this file as a string and I get the same data but when I try to convert this in binary bytes[] the file become corrupt.

How can I achieve this ?

I use something like this to convert

var ss = sr.ReadToEnd();

 MemoryStream stream = new MemoryStream();
 StreamWriter writer = new StreamWriter(stream);

 writer.Write(ss);
 writer.Flush();
 stream.Position = 0;  

 var bytes = default(byte[]);

 bytes = stream.ToArray();

Answer 1

This looks like base 64. Use:

System.Convert.ToBase64String(b)

https://msdn.microsoft.com/en-us/library/dhx0d524%28v=vs.110%29.aspx

And

System.Convert.FromBase64String(s)

https://msdn.microsoft.com/en-us/library/system.convert.frombase64string%28v=vs.110%29.aspx

Answer 2

You need to de-code it from base64 , like this:

Assuming you've read the file into ss as a string.

var bytes = Convert.FromBase64String(ss);

Answer 3

There are several things going on here. You need to know the encoding for the default StreamWriter , if it is not specified it defaults to UTF-8 encoding. However, .NET strings are always either UNICODE or UTF-16 .

MemoryStream from string - confusion about Encoding to use

I would suggest using System.Convert.ToBase64String(someByteArray) and its counterpart System.Convert.FromBase64String(someString) to handle this for you.