未将对象引用设置到对象的实例

对象引用没有设置到对象实例的原因很多：
1、如下：

public int Revise(ref int numline, ref int numcircle, ref int numtext,System.IO.StreamWriter str_w, List< string >
record,EXT extend,Line []
lines, Circle[] circles, Text []
texts)
[align=left] {[/align]
string []
record1 =record.ToArray();
for (int i
= 0; i < record1.Length;i++ )
[align=left] {[/align]
string temp
= string .Empty;
[align=left] temp = record1[i];[/align]
if (temp
== "$EXTMIN" )
[align=left] {[/align]
record1[i + 2] = Convert .ToString(extend.Min_x)
;
[align=left] record1[i + 4] = Convert .ToString(extend.Min_y);[/align]
[align=left] record1[i + 6] = Convert .ToString(extend.min_z);[/align]
[align=left] record1[i + 10] = Convert .ToString(extend.Max_x);[/align]
[align=left] record1[i + 12] = Convert .ToString(extend.Max_y);[/align]
[align=left] record1[i + 14] = Convert .ToString(extend.Max_z);[/align]
[align=left] i += 14;[/align]
[align=left] continue ;[/align]
[align=left] }[/align]
if (temp
== "AcDbLine" )
[align=left] {[/align]
[align=left] record1[i + 2]= Convert .ToString(lines[numline].x1);//此处开始报错[/align]
[align=left] record1[i + 4] = Convert .ToString(lines[numline].y1);[/align]
[align=left] record1[i + 6] = Convert .ToString(lines[numline].z1);[/align]
[align=left] record1[i + 8] = Convert .ToString(lines[numline].x2);[/align]
record1[i + 10] = Convert .ToString(lines[numline].y2)
;
[align=left] record1[i + 12] = Convert .ToString(lines[numline].z2);[/align]
[align=left] numline--;[/align]
[align=left] i += 12;[/align]
[align=left] continue ;[/align]
[align=left] }[/align]
[align=left] }[/align]

for (int i
= 0; i < record1.Length;i++ )
[align=left] {[/align]
[align=left] str_w.WriteLine(record1[i]);[/align]
[align=left] }[/align]
[align=left] return 1;[/align]
[align=left] }[/align]

[align=left]其中numline,numcircle,numtext，代表的line，circle，text对象的个数[/align]
[align=left]原因就在于，数组的下标总是比个数小1，假如有5个元素，我们尝试给lines[5]赋值，而lines[5]已经越界，更不可能初始化。[/align]

[align=left]2、对于数组，不光要实例化数组，还要实例化数组的对象[/align]

public int Read_Entities(ref int numpolyline, Polyline []
plines,System.IO. StreamReader str_r)
[align=left] {[/align]
string buff
= string .Empty;
[align=left] buff = str_r.ReadLine();[/align]
//int numline
= 0;
//int numcircle
= 0;
[align=left] //int numtext=0;[/align]
while (buff
!= "OBJECTS" )
[align=left] {[/align]
[align=left] [/align]
if (buff
== "LWPOLYLINE" )
[align=left] {[/align]
while (buff
!= "AcDbPolyline" )
[align=left] {[/align]
[align=left] buff = str_r.ReadLine();[/align]
[align=left] }[/align]
[align=left] plines[numpolyline] = new Polyline ();//(1)[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] plines[numpolyline].pointnum = Convert .ToInt32(str_r.ReadLine());[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] plines[numpolyline].points = new point [plines[numpolyline].pointnum];//(2)[/align]
[align=left] for (int i=0;i<plines[numpolyline].pointnum;i++)[/align]
[align=left] {[/align]
[align=left] plines[numpolyline].points[i] = new point ();//(3)[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] plines[numpolyline].points[i].x = Convert .ToDouble(str_r.ReadLine());[/align]
[align=left] str_r.ReadLine();[/align]
[align=left] plines[numpolyline].points[i].y = Convert .ToDouble(str_r.ReadLine());[/align]
[align=left] }[/align]

[align=left] }[/align]
[align=left] buff = str_r.ReadLine();[/align]
[align=left] }[/align]
[align=left] return 1;[/align]
[align=left] }[/align]
[align=left]其中，多线由多个点组成[/align]
[align=left]注释（1）处：初始化polyline对象[/align]
[align=left]注释（2）处：初试化point数组[/align]
[align=left]注释（3）处：初始化点对象实例[/align]
[align=left]一直忘记了第二个，导致一直提示错误[/align]

待续。。。