当T不同时，是否有可能获得列表<T>的项目数？

Question

我有一个子程序，稍微改变其操作以包括一个列表或其他，然后执行相同的操作。由于它只计算列表中的项目数量，所以我认为无论列表类型如何，都可能有一种简单的方法来获取项目计数。

在此先感谢！

编辑：

private List<Message> currentMessages; 
private List<Lead> currentLeads; 
... 
private void nextLeadBtn_Click(object sender, EventArgs e) 
    { 
     object temp; 
     if (includeAllCheck.Checked) 
     { 

      temp = currentMessages; 
      if (SelectedLead == (currentMessages.Count - 1)) 
       SelectedLead = 0; 
      else 
       SelectedLead += 1; 
     } 
     else 
     { 
      temp = currentLeads; 
      if (SelectedLead == (currentLeads.Count - 1)) 
       SelectedLead = 0; 
      else 
       SelectedLead += 1; 
     } 
     // This is what I want to replace the above with 
     //if (SelectedLead == ((List)temp).Count - 1) //obviously this does not work 
     // SelectedLead = 0; 
     //else 
     // SelectedLead += 1; 




     LoadPreviews(includeAllCheck.Checked); 
    } 

Answer 1

您可以随时使用ICollection.Count，如果你不想处理仿制药。 List<T>执行ICollection，所以你可以随时访问。

编辑：既然你已经张贴你的代码，你可以改变该行：

if (SelectedLead == ((List)temp).Count - 1) // won't compile, of course 

到

if (SelectedLead == ((ICollection)temp).Count - 1) // happy as a clam 

事实上，一个更好的选择将将object temp的声明更改为ICollection temp以更好地传达类型信息，并完全避免所有此类废话。

Answer 2

ICollection temp; 
     if (includeAllCheck.Checked) 
     { 

      temp = currentMessages;    
     } 
     else 
     { 
      temp = currentLeads; 

     } 
if (SelectedLead == (temp.Count - 1)) 
       SelectedLead = 0; 
      else 
       SelectedLead += 1;