未将对象引用设置到对象的实例,怎么解决??

[晒屁屁]

int re=0;
string buf=new String('\0',1024);
int siz=1024;
re=WinApi.GetComputerName(buf,siz);//在这句时出错
buf.Substring(0,buf.IndexOf('\0'));
Debug.WriteLine(buf);

[saucer]

try

using System;
using System.Text;
using System.Runtime.InteropServices;

[DllImport("kernel32.dll", SetLastError=true, CharSet=CharSet.Auto)]
[return:MarshalAs(UnmanagedType.Bool)]
public static extern bool GetComputerName(
StringBuilder lpBuffer,
[MarshalAs(UnmanagedType.U4)] ref int lpnSize);

int re=0;
StringBuilder buf = new StringBuilder("",1024);
int siz=1024;
bool bOK = GetComputerName(buf,ref siz);
Debug.WriteLine(buf.ToString());

[晒屁屁]

试成功了,能讲讲为什么吗,还有为什么经常会有这种错误呢?我是指在别的情况下,这种错误一般是怎么回事呢?谢谢~

[slayersun]

等待答案

[saucer]

1. you need to declare GetComputerName as static
2. GetComputerName will fill the name in the first parameter you pass in, so you need to give it a StringBuilder or a byte[]
3. it also changes the last parameter to let you know how many long the name is

[fushuming]

gz