如何将以下的JAVASCRIPT代码改写为C# 超难问题

[sanshisong]

var output = [];
var chr1, chr2, chr3;
var enc1, enc2, enc3, enc4;
var i = 0;

input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
var l = input.length;
while (i < l) {
enc1 = this._keyStr.indexOf(input.charAt(i++));
enc2 = this._keyStr.indexOf(input.charAt(i++));
enc3 = this._keyStr.indexOf(input.charAt(i++));
enc4 = this._keyStr.indexOf(input.charAt(i++));

chr1 = (enc1 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;

output.push(String.fromCharCode(chr1));

if (enc3 != 64) {
output.push(String.fromCharCode(chr2));
}
if (enc4 != 64) {
output.push(String.fromCharCode(chr3));
}
}

[tidelgl]

帮顶

[sanshisong]

有会的么

[wcwtitxu]

byte[] bytes = Convert.FromBase64String(input);
string result = Encoding.Default.GetString(bytes);
Console.WriteLine(result);