选择两个不同的变量“集合”。在没有两个循环的循环条件的基础上C＃中的listview项目，我该怎么做？

问题描述

如何在C＃WinForm中预先选择listView项的变量集合，并为每个项目添加不同的数据类型，然后我进入循环迭代项目而不实际加倍循环本身以应用条件？

  bool  SelectAll =  false ;  //  可以是true或false它是一个变量设置...  
  var  myItems =  null ;  //  这里第一个错误，初始化需要var而不能为null，那该怎么办？它必须是一个空类型才能在var中预先选择一个类型，否则var不能再被改变为另一个类型。 
 
  / *  这里应该决定哪个项目集合需要花费b $ b来循环。是的，我只是可以使用所有这些代码放置两个循环，但是这会重复所有这些。我不能做的函数，因为ListViewItemCollection和ListViewSelectedItemCollection的数据类型不相同，并且枚举不允许对象类型（我试过）！* /  
 
  if （SelectAll ==  true ）
 {
 myItems = listView1.Items;  //  问题：此Listview集合与下面的其他数据类型不同！ 
} 
  else  
 {
 myItems = listView1.SelectedItems;  //  问题：此Listview集合与上面的其他数据类型不同！ 
} 
 
  foreach （ListViewItem XYZ  in  myItems） //  这里的循环不会重复通过条件，只有一个循环，但循环的项目选择可能不同 
 {
  //   ...中间有许多代码行 
 } 

我尝试过：



尝试'var'数据类型（需要初始化，不能用null初始化，如果我用第一个数据类型初始化我以后不能再添加其他数据类型。它似乎不是可枚举的，不允许返回在函数中）



尝试'对象'数据类型（不能用作en在循环中无法理解）



尝试将'ListViewItemCollection'作为ienumerable，但它不能采用像'ListViewSelectedItemCollection'这样的另一种类型。



所有代码条件重复的第二个循环是我不想要的！

我尝试了一个函数，但返回数据类型因条件而异，它可以是'ListViewItemCollection'或'ListViewSelectedItemCollection'。所以一个函数也不适用。



在循环之前是否有人想要变量项选择？

解决方案

How would I pre-select a variable collection of listView items in C# WinForm with a different datatype for each, before I enter a loop with iterating through the items without doubling actually the loop itself for applying the condition?

bool SelectAll=false; //can be true or false it is a variable setting...
var myItems=null; //here first error, initialization is required of "var" and cannot be "null", so what to do? it must be an empty type to not preselect a type in var, else var cannot be changed anymore to another type.

/*here shall be the decision which collection of items shall 
be taken to loop through. Yes, I simply could put two loops with all this code, but that would suck to repeat all this. A function I cannot do, because the data type of the ListViewItemCollection and ListViewSelectedItemCollection is not the same and an object type is not allowed for enumeration (I tried it)!*/

if(SelectAll==true)
{
myItems=listView1.Items; //problem: this Listview Collection is a different data type as the other below!
}
else
{
myItems=listView1.SelectedItems; //problem: this Listview Collection is a different data type as the other above!
}

foreach(ListViewItem XYZ in myItems) //here shall be the loop not repeat through the condition, just one loop but the selection of the items to loop through could be different
{
//...many lines of codes inbetween
}

What I have tried:

tried 'var' datatype (needs to be initialized, cannot be initialized with null, if I initialize with the first data type I cannot later put another data type on it. it seems not to be enumerable and is not allowed to be returned in a function)

tried 'object' datatype (cannot be used as enumerable in the loop)

tried 'ListViewItemCollection' as ienumerable, but it cannot take another type like 'ListViewSelectedItemCollection'.

A second loop with all the code conditional repeated is what I do not want!
I tried a function, but the return datatype varies on a condition, it can be either 'ListViewItemCollection' or 'ListViewSelectedItemCollection'. So a function doesn't apply either.

Has someone another idea for variable items selection before the loop?

解决方案

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