blocks|key|446169|text|在迭代(使用foreach)集合时，不能修改集合。相反，使用反向for循环：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|446170|ListBox.SelectedObjectCollection+selectedItems+=+new+ListBox.SelectedObjectCollection(lstClientes);
selectedItems+=+lstClientes.SelectedItems;

if+(lstClientes.SelectedIndex+!=+-1)
{+
++++for+(int+i+=+selectedItems.Count+-+1;+i+>=+0;+i--)
++++++++lstClientes.Items.Remove(selectedItems[i]);
}
else
++++MessageBox.Show("Debe+seleccionar+un+email");|code-block|syntax|javascript|446171|使用反向循环可以确保您在删除它们之后不会跳过它们。|446172|entityMap^0|6|7|W|3|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

You can't modify a collection while iterating (using a <code>foreach</code>) through it. Instead use a reverse <code>for</code> loop:

<pre><code>ListBox.SelectedObjectCollection selectedItems = new ListBox.SelectedObjectCollection(lstClientes);
selectedItems = lstClientes.SelectedItems;

if (lstClientes.SelectedIndex != -1)
{ 
 for (int i = selectedItems.Count - 1; i &gt;= 0; i--)
 lstClientes.Items.Remove(selectedItems[i]);
}
else
 MessageBox.Show("Debe seleccionar un email");
</code></pre>

Using a reverse loop ensures you don't skip over any after removing them.

blocks|key|446146|text|selectedItems+=+lstClientes.SelectedItems;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|446147|这一行不会创建新的集合，但会设置对列表框中集合的引用。因此，您正在迭代一个集合，并尝试一次从集合中移除项。这是不可能的|unstyled|446148|您可以使用此命令，例如：|446149|foreach+(string+s+in+lstClientes.SelectedItems.OfType<string>().ToList())
+++lstClientes.Items.Remove(s);|446150|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$B|C]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>selectedItems = lstClientes.SelectedItems;
</code></pre>

This line does not create a new collection, but sets a reference to the one in a listbox. So you are iterating through a collection and try to remove items from it at once. It is not possible

You could use this, for example:

<pre><code>foreach (string s in lstClientes.SelectedItems.OfType&lt;string&gt;().ToList())
 lstClientes.Items.Remove(s);
</code></pre>

blocks|key|228115|text|就像这样简单：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|228116|while+(lst.SelectedItems.Count+>+0)
{
+++lst.Items.Remove(lst.SelectedItems[0]);
}|code-block|syntax|javascript|228117|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Simple just like this:

<pre><code>while (lst.SelectedItems.Count &gt; 0)
{
 lst.Items.Remove(lst.SelectedItems[0]);
}
</code></pre>

blocks|key|228153|text|lst.Items.Remove(lst.Items[lst.SelectedIndex]);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|228154|如果你不想循环，你可以使用这个|unstyled|228155|注意:这只适用于删除1个项目(多个选择将只删除第一个选定的项目)|228156|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>lst.Items.Remove(lst.Items[lst.SelectedIndex]);
</code></pre>

You can use this if you don't want to loop

Note: This only works to remove 1 item (multiple selections it will only remove the first selected item)

blocks|key|228425|text|为了基于Patrick的答案，我倾向于使用反向索引删除，因为它保留了待删除的项的索引，而不是删除相同的项。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|228426|private+void+BtnDelete_Click(object+sender,+EventArgs+e)+{
++++if+(listBox.SelectedIndex+==+-1)+{
++++++++return;
++++}

++++//+Remove+each+item+in+reverse+order+to+maintain+integrity
++++var+selectedIndices+=+new+List<int>(listBox.SelectedIndices.Cast<int>());
++++selectedIndices.Reverse();
++++selectedIndices.ForEach(index+=>+listBox.Items.RemoveAt(index));
}|code-block|syntax|javascript|228427|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

To build on Patrick's answer I tend to use a reverse index removal as it retains the index of items pending removal while they're being removed without removing identical items.

<pre><code>private void BtnDelete_Click(object sender, EventArgs e) {
 if (listBox.SelectedIndex == -1) {
 return;
 }

 // Remove each item in reverse order to maintain integrity
 var selectedIndices = new List&lt;int&gt;(listBox.SelectedIndices.Cast&lt;int&gt;());
 selectedIndices.Reverse();
 selectedIndices.ForEach(index =&gt; listBox.Items.RemoveAt(index));
}
</code></pre>

blocks|key|228136|text|我找到了更好的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|228137|++++++++if+(listBoxIn.SelectedItems.Count+!=+0)
++++++++{
++++++++++++while+(listBoxIn.SelectedIndex!=-1)
++++++++++++{
++++++++++++++++listBoxIn.Items.RemoveAt(listBoxIn.SelectedIndex);++++++++++++++++++
++++++++++++}
++++++++}|code-block|syntax|javascript|228138|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I found better solution. 

<pre><code> if (listBoxIn.SelectedItems.Count != 0)
 {
 while (listBoxIn.SelectedIndex!=-1)
 {
 listBoxIn.Items.RemoveAt(listBoxIn.SelectedIndex); 
 }
 }
</code></pre>

blocks|key|446291|text|我今天遇到了同样的问题，想要更简洁的东西，于是想出了这个Linq解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|446292|foreach+(int+index+in+myListBox.SelectedIndices.Cast<int>().Select(x+=>+x).Reverse())
++++myListBox.Items.RemoveAt(index);|code-block|syntax|javascript|446293|基本上与Patrick的向后迭代和删除选定项的解决方案相同。然而，我们不是向后迭代，而是反转要删除的项列表并向前迭代。我们不再遍历原始枚举，因此允许移除foreach中的项。|446294|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I encountered this same problem today and wanted something a bit cleaner, and came up with this Linq solution:

<pre><code>foreach (int index in myListBox.SelectedIndices.Cast&lt;int&gt;().Select(x =&gt; x).Reverse())
 myListBox.Items.RemoveAt(index);
</code></pre>

Basically the same as Patrick's solution of iterating backwards and removing selected items. However instead of iterating backwards, we reverse the list of items to remove and iterate forwards. We no longer iterate over the original enumeration, so we are allowed to remove items within the foreach.

blocks|key|446257|text|这是删除所选项目的最简单方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|446258|+for(int+v=0;+v<listBox1.SelectedItems.Count;+v%2B%2B)+{
++++++++++++listBox1.Items.Remove(listBox1.SelectedItems[v]);
++++++++}|code-block|syntax|javascript|446259|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is the most easiest way to remove selected items

<pre><code> for(int v=0; v&lt;listBox1.SelectedItems.Count; v++) {
 listBox1.Items.Remove(listBox1.SelectedItems[v]);
 }
</code></pre>

blocks|key|446343|text|创建一个全局变量：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|446344|public+partial+class+Form1+:+Form
++++{

++++++++Int32+index;
++++}|code-block|syntax|javascript|446345|然后，在选定的索引更改时，将该索引保存在您定义的变量中：|446346|+private+void+lsbx_layers_SelectedIndexChanged(object+sender,+EventArgs+e)
++++++++{

+++++++++++layerindex+=+lsbx_layers.SelectedIndices[0];//selected+index+that+has+fired+the+event
+++++++++}|446347|最后，删除元素：|446348|+lsbx_layers.Items.RemoveAt(Layerindex);|446349|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Create a global variable:

<pre><code>public partial class Form1 : Form
 {

 Int32 index;
 }
</code></pre>

Then at the selected index change save that index in the var you defined :

<pre><code> private void lsbx_layers_SelectedIndexChanged(object sender, EventArgs e)
 {

 layerindex = lsbx_layers.SelectedIndices[0];//selected index that has fired the event
 }
</code></pre>

Finally ,remove the element :

<pre><code> lsbx_layers.Items.RemoveAt(Layerindex);
</code></pre>

I want to do that but, the listbox changes on every deletion, so it throws runtime exception even if I tried to do a new object.

I tried like this:

<pre><code>ListBox.SelectedObjectCollection selectedItems = new ListBox.SelectedObjectCollection(lstClientes);
 selectedItems = lstClientes.SelectedItems;
if (lstClientes.SelectedIndex != -1)
{ 
 foreach (string s in selectedItems)
 lstClientes.Items.Remove(s);
}
else
 MessageBox.Show("Debe seleccionar un email");
</code></pre>

Delete selected items from listbox

我想这样做，但是，列表框在每次删除时都会改变，所以即使我试图创建一个新对象，它也会抛出运行时异常。我试过这样做：ListBox.SelectedObjectCollection selectedItems = new ListBox.SelectedObjectCollection(lstClientes);   selectedItems = lstClientes.SelectedItems;

问从列表框中删除所选项目
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