前言：
现在很多STMP服务器在发送邮件时均需重新认证一遍，而Delphi的TNMSMTP控件对它没有很“可视化”的支持，使很多人在开发过程中大打问号。
由于前段时间在做《CSDN查询助手》的时候，使用的也是需认证的服务器（163.com）。从其它地方摘取了部分代码得以解决，现在此发布与大家共享。
实现：
1、在NMSMTP的OnConnect事件中添加代码：
var strUserName, strPassword: String;
begin
strUserName := EncodeString('CoolSlob');//CoolSlob是服务器的帐号
strPassword := EncodeString('Password');//Password是密码
{进行认证，输入编码后的用户名、密码}
nmsmtp1.Transaction('EHLO') ;
nmsmtp1.Transaction('AUTH LOGIN');
nmsmtp1.Transaction(strUserName);
nmsmtp1.Transaction(strPassword);
StatusBar1.SimpleText := '连接成功';
end;
2、EncodeString函数实现过程：
{对参数Decoded字符串进行Base64编码，返回编码后的字符串}
function EncodeString(Decoded:string):String;
var
mmTemp,mmDecoded:TMemoryStream;
strTemp:TStrings;
begin
mmTemp := TMemoryStream.Create;
mmDecoded:=TMemoryStream.Create;
strTemp:=TStringList.Create;
strTemp.Add(Decoded);
strTemp.SaveToStream(mmTemp);
mmTemp.Position := 0;
{剔除mmTemp从strTemp中带来的字符#13#10}
mmDecoded.CopyFrom(mmTemp,mmTemp.Size-2);
{对mmDecoded进行Base64编码，由mmTemp返回编码后的结果}
EncodeBASE64(mmTemp,mmDecoded);
{获得Base64编码后的字符串}
mmTemp.Position:=0;
strTemp.LoadFromStream(mmTemp);
{返回结果必须从strTemp[0]中获得，如果使用strTemp.Text会
带来不必要的字符#13#10}
Result:=strTemp[0];
end;
3、EncodeBASE64函数实现过程：
function EncodeBASE64(Encoded: TMemoryStream ; Decoded: TMemoryStream): Integer;
const
_Code64: String[64] =
('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/');
var
I: LongInt;
B: array[0..2279] of Byte;
J, K, L, M, Quads: Integer;
Stream: string[76];
EncLine: String;
begin
Encoded.Clear;
Stream := '';
Quads := 0;
{为提高效率，每2280字节流为一组进行编码}
J := Decoded.Size div 2280;
Decoded.Position := 0;
{对前J*2280个字节流进行编码}
for I := 1 to J do
begin
Decoded.Read(B, 2280);
for M := 0 to 39 do
begin
for K := 0 to 18 do
begin
L:= 57*M + 3*K;
Stream[Quads+1] := _Code64[(B[L] div 4)+1];
Stream[Quads+2] := _Code64[(B[L] mod 4)*16 + (B[L+1] div 16)+1];
Stream[Quads+3] := _Code64[(B[L+1] mod 16)*4 + (B[L+2] div 64)+1];
Stream[Quads+4] := _Code64[B[L+2] mod 64+1];
Inc(Quads, 4);
if Quads = 76 then
begin
Stream[0] := #76;
EncLine := Stream+#13#10;
Encoded.Write(EncLine[1], Length(EncLine));
Quads := 0;
end;
end;
end;
end;
{对以2280为模的余数字节流进行编码}
J := (Decoded.Size mod 2280) div 3;
for I := 1 to J do
begin
Decoded.Read(B, 3);
Stream[Quads+1] := _Code64[(B[0] div 4)+1];
Stream[Quads+2] := _Code64[(B[0] mod 4)*16 + (B[1] div 16)+1];
Stream[Quads+3] := _Code64[(B[1] mod 16)*4 + (B[2] div 64)+1];
Stream[Quads+4] := _Code64[B[2] mod 64+1];
Inc(Quads, 4);
{每行76个字符}
if Quads = 76 then
begin
Stream[0] := #76;
EncLine := Stream+#13#10;
Encoded.Write(EncLine[1], Length(EncLine));
Quads := 0;
end;
end;
{“=”补位}
if (Decoded.Size mod 3) = 2 then
begin
Decoded.Read(B, 2);
Stream[Quads+1] := _Code64[(B[0] div 4)+1];
Stream[Quads+2] := _Code64[(B[0] mod 4)*16 + (B[1] div 16)+1];
Stream[Quads+3] := _Code64[(B[1] mod 16)*4 + 1];
Stream[Quads+4] := '=';
Inc(Quads, 4);
end;
if (Decoded.Size mod 3) = 1 then
begin
Decoded.Read(B, 1);
Stream[Quads+1] := _Code64[(B[0] div 4)+1];
Stream[Quads+2] := _Code64[(B[0] mod 4)*16 + 1];
Stream[Quads+3] := '=';
Stream[Quads+4] := '=';
Inc(Quads, 4);
end;
Stream[0] := Chr(Quads);
if Quads > 0 then
begin
EncLine := Stream+#13#10;
Encoded.Write(EncLine[1], Length(EncLine));
end;
Result := Encoded.Size;
end;
声明：
上述代码非本人所作，由于不知其原始出处，故仍作为“原创”！
