在Asp.Net ListView控件编程方式选择项 [英] Programmatically Select Item in Asp.Net ListView
问题描述
做一个快速搜索后，我找不到答案，这个看似简单的事。
After doing a quick search I can't find the answer to this seemingly simple thing to do.
如何手动在Asp.Net ListView中选择一个项目？
我有一个SelectedItemTemplate，但我不希望使用一个asp：按钮或ASP：LinkButton的选择项目。我希望它从一个URL来完成。像查询字符串，例如
I have a SelectedItemTemplate, but I don't want to use an asp:button or asp:LinkButton to select an item. I want it to be done from a URL. Like a QueryString, for example.
我想将是对的ItemDataBound的方式，检查条件，然后将其设置为如果属实选择，但我怎么做到这一点？
The way I imagine would be on ItemDataBound, check a condition and then set it to selected if true, but how do I do this?
例如：
protected void lv_ItemDataBound(object sender, ListViewItemEventArgs e) {
using (ListViewDataItem dataItem = (ListViewDataItem)e.Item) {
if (dataItem != null) {
if( /* item select condition */ ) {
// What do I do here to Set this Item to be Selected?
// edit: Here's the solution I'm using :
((ListView)sender).SelectedIndex = dataItem.DisplayIndex;
// Note, I get here and it gets set
// but the SelectedItemTemplate isn't applied!!!
}
}
}
}
我敢肯定，这是code的一行或两行。
I'm sure it's one or two lines of code.
编辑：我已经更新了code，以反映该解决方案，似乎我能选择ListView的SelectedItemIndex，但是，它不是实际渲染SelectedItemTemplate。我不知道我是否应该在ItemDataBound事件做这个的建议如下
I've updated the code to reflect the solution, and it seems that I can select the ListView's SelectedItemIndex, however, it's not actually rendering the SelectedItemTemplate. I don't know if I should be doing this in the ItemDataBound event as suggested below.
推荐答案
我看了一些什么引擎盖下将在ListView控件，并认为这可能是最好的办法。
I looked at some of what's going on in ListView under the hood and think this is probably the best approach.
void listView_ItemCreated(object sender, ListViewItemEventArgs e)
{
// exit if we have already selected an item; This is mainly helpful for
// postbacks, and will also serve to stop processing once we've found our
// key; Optionally we could remove the ItemCreated event from the ListView
// here instead of just returning.
if ( listView.SelectedIndex > -1 ) return;
ListViewDataItem item = e.Item as ListViewDataItem;
// check to see if the item is the one we want to select (arbitrary) just return true if you want it selected
if (DoSelectDataItem(item)==true)
{
// setting the SelectedIndex is all we really need to do unless
// we want to change the template the item will use to render;
listView.SelectedIndex = item.DisplayIndex;
if ( listView.SelectedItemTemplate != null )
{
// Unfortunately ListView has already a selected a template to use;
// so clear that out
e.Item.Controls.Clear();
// intantiate the SelectedItemTemplate in our item;
// ListView will DataBind it for us later after ItemCreated has finished!
listView.SelectedItemTemplate.InstantiateIn(e.Item);
}
}
}
bool DoSelectDataItem(ListViewDataItem item)
{
return item.DisplayIndex == 0; // selects the first item in the list (this is just an example after all; keeping it simple :D )
}
注意
- 的ListView选择它的数据绑定事件触发后的项目将使用的模板。所以，如果selectedIndex为前接盘，没有更多的工作是必要
- 设置的SelectedIndex数据绑定工作后的任何地方，你只是没有得到SelectedItemTemplate。对于你或者重新绑定的数据;重新实例或在ListViewItem的的SelectedItemTemplate。 请务必先清除ListViewItem.Controls集合！的
- ListView selects the template an item will use after it's DataBinding event fires. So if the SelectedIndex is set before then, no more work is necessary
- Setting the SelectedIndex anywhere after DataBinding works, you just don't get the SelectedItemTemplate. For that you have either rebind the data; or reinstantiate the SelectedItemTemplate on the ListViewItem. be sure to clear the ListViewItem.Controls collection first!
更新我已删除了我的大部分原来的解决方案，因为这应该工作更多的情况下，更好。
UPDATE I have removed most of my original solution, since this should work better and for more cases.
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