Validate string as Proper Base64String and Convert to byte[]

Question

Hi all,

 

i want to validate input string is Valid Base64String or not, if its valid then convert into byte[].

 

i try following solutions

1) Use RegEx

2) Use MemoryStream

3) Use Convert.FromBase64String

 

For example i want to validate this string "932rnqia38y2" its Base64String or not and then convert to byte[], this string is not valid Base64String but i am always getting true or valid in my code.

 

please let me know if you have any solutions.

 

**Code..**

//Regex _rx = new Regex(@"^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}[AEIMQUYcgkosw048]=|[A-Za-z0-9+/][AQgw]==)?$", RegexOptions.Compiled);

Regex _rx = new Regex(@"^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$", RegexOptions.Compiled);

if (image == null) return null;

if ((image.Length % 4 == 0) && _rx.IsMatch(image))

{

try

{

//MemoryStream stream = new MemoryStream(Convert.FromBase64String(image));

return Convert.FromBase64String(image);

}

catch (FormatException)

{

return null;

}

}