foreach的函数，怎么改成用for循环写，肯请指点

Question

ArrayList　categories=this.Eric_ArticleCategories.GetTopCategory();
int j=0;
foreach(DataAccess.ArticleCategoriesDetails category in categories)
{
j++;
dr=dt.NewRow();
dr["ID"]=category.ID;
if(j!=categories.Count)
{
dr["categoryName"]="©À©¤"+category.categoryName;
}
else
{
dr["categoryName"]="©¸©¤"+category.categoryName;
}
dt.Rows.Add(dr);
this.ListChildCategory(category.childStr.Trim(),ref dt,dr,dc,out strMsg);
}
这个是用foreach语句实现的，如果改用for循环应该如何写啊，肯请指点

Answer 1

ArrayList　categories=this.Eric_ArticleCategories.GetTopCategory();
int j=0;
for(int i=0; i<categories.count; i++)
{
DataAccess.ArticleCategoriesDetails category = categories[i] as DataAccess.ArticleCategoriesDetails;
j++;
dr=dt.NewRow();
dr["ID"]=category.ID;
if(j!=categories.Count)
{
dr["categoryName"]="&copy;&Agrave;&copy;¤"+category.categoryName;
}
else
{
dr["categoryName"]="&copy;&cedil;&copy;¤"+category.categoryName;
}
dt.Rows.Add(dr);
this.ListChildCategory(category.childStr.Trim(),ref dt,dr,dc,out strMsg);}

Answer 2

for(int i=0; i<categories.count; i++)