ArrayList中Add的一个问题求解

[rogerfz]

见代码：
public class Stock
{
public Color m_Color;
public String m_Ticker;
public float[] m_Price;
}



ArrayList m_StockList = new ArrayList();
Stock aStock = new Stock();
aStock.m_Ticker = "MSFT";
aStock.m_Color = Color.Red;
aStock.m_Price = new float[5] { 36.1F, 71.3F, 119.35F, 45.2F, 64.9F };
m_StockList.Add(aStock);

aStock.m_Ticker = "INTL";
aStock.m_Color = Color.Blue;
aStock.m_Price = new float[5] { 10.3F, 23.34F, 22.2F, 8.78F, 20.19F };
m_StockList.Add(bStock);

aStock.m_Ticker = "ORCL";
aStock.m_Color = Color.Green;
aStock.m_Price = new float[5] { 20.3F, 123.34F, 52.2F, 68.78F, 70.19F };
m_StockList.Add(cStock);

为何对m_StockList增加了3次，每次增加的都是不一样的，但是为什么查看m_StockList时有3个相同的东西呢，都是为最后一个

[wuyq11]

Stock aStock = new Stock();

m_StockList.Add(aStock);
aStock=null;
aStock =new Stock();
指向同一个对象

[s136735431]

引用类型保存的是地址，可以把多创建几个Stock的对象，你这个写法会覆盖原值。
ArrayList m_StockList = new ArrayList();
Stock aStock = new Stock();
aStock.m_Ticker = "MSFT";
aStock.m_Color = Color.Red;
aStock.m_Price = new float[5] { 36.1F, 71.3F, 119.35F, 45.2F, 64.9F };
m_StockList.Add(aStock);

Stock bStock = new Stock();
bStock.m_Ticker = "INTL";
bStock.m_Color = Color.Blue;
bStock.m_Price = new float[5] { 10.3F, 23.34F, 22.2F, 8.78F, 20.19F };
m_StockList.Add(bStock);

Stock cStock = new Stock();
cStock.m_Ticker = "ORCL";
cStock.m_Color = Color.Green;
cStock.m_Price = new float[5] { 20.3F, 123.34F, 52.2F, 68.78F, 70.19F };
m_StockList.Add(cStock);