问题描述
我遇到这样的异常:
我在viewModel中有一个属性:
I have a property in viewModel:
private ObservableCollection<TreeViewItem> fooStorage=new ObservableCollection<TreeViewItem>();
public ObservableCollection<TreeViewItem> FooStorage
{
get { return facetStorage; }
set { facetStorage = value; }
}
但是，在我清除FooStorage并尝试添加新项目之后:
However, after I cleared FooStorage and trying to add new item:
private void LoadData()
{
if (FooStorage.Count > 0)
{
FooStorage.Clear();
}
for (int k = 0; k < lengthOfColl; k++)
{
FooStorage.Add(new TreeViewItem() { Header=k.ToString()});//here is exception
}
}
我有一个例外.
当我第一次调用LoadData()方法时，一切正常.然后，如果我第二次调用方法LoadData()，则会收到此类异常.
When I call a method LoadData() at the first time, it all works okay. Then if I call a method LoadData() at the second time, then I get a such exception.
有人遇到过这样的例外吗?我无法在测试项目中重现此异常的最有趣的事情.
Have anybody met a such exception? The most interesting thing that I cannot reproduce this exception in a test project.
StackTrace:
StackTrace:
更新:
我正在从FooStorage向位于DataGridTextBoxColumn的HeaderTemplate内的其他TreeView添加新的TreeViewItem's.因此，当用户单击DataGridTextBoxColumn2的Header1时，Header1的TreeView将由viewModel中的FooStorage填充.好的.当用户单击DataGridTextBoxColumn2的Header2时，应从viewModel中的FooStorage填充Header2的TreeView，但是当我Clear()和Add()新项添加到FooStorage时，则我上面有一个例外.
I am adding new TreeViewItem's from FooStorage to different TreeView placed inside of HeaderTemplate of DataGridTextBoxColumn. So when user clicks at Header1 of DataGridTextBoxColumn2, then TreeView of Header1 is populated by FooStorage from viewModel. OK. The when user clicks at Header2 of DataGridTextBoxColumn2, then TreeView of Header2 should be populated by FooStorage from viewModel, however when I Clear() and Add() new items to FooStorage, then I've got an above exception.
推荐答案
只想说将UI元素TreeViewItem传递给ViewModel是一种不好的做法.所以也许添加新的TreeViewItem然后在不同的地方使用是我的问题.
Just would like to say that passing UI Element TreeViewItem to ViewModel is a bad practice. So maybe adding new TreeViewItem which is then used in different places was my problem.
正如@Sinatr所说:
As @Sinatr said:
帕特里克·霍夫曼(Patrick Hofman)给了我建议，以在用户界面中禁用该部分，然后在禁用它之后，就没有问题了.
Patrick Hofman gave me advice to disable that section in the UI and after I disabled it, then there was no problems.
因此，我得出的结论是，我已经遭受了不良习惯的后果，并受到了惩罚. 避免不良做法.而ObservableCollection<T>则无罪！抱歉，ObservableCollection<T>.
So I've concluded that I've met consequences of using bad practice and was punished. Avoid bad practices. And ObservableCollection<T> is not guilty! Sorry, ObservableCollection<T>.
现在我正在学习TreeView由乔什·史密斯(Josh Smith).
这篇关于“指定的参数超出有效值范围.参数名称:索引"当将新项目添加到ObservableCollection< T>时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！