维护DropDownList选择的索引 [英] Maintaining DropDownList selected index

问题描述

提前致谢！我想在回发时维护一个dl列表的选定索引

。我正在做的是当一个人从

下拉列表中选择一个项目时，我在日历控件中选择一个日期并用日期填充一个

文本框。为此，我将自动回发设置为下拉列表

。但它总是在帖子后面重置选定的索引。我在onLoad方法中对此进行
控制......


如果不是Page.IsPostBack那么


如果页面回发我选择日期并正确填充textbox.text

。选定的索引丢失。我甚至用选定的索引在

视图状态中添加了一个键，并尝试从

中获取值，但仍然没有。请帮助！

Thanks in advance! I''m trying to maintain a dl list''s selected index
on postback. What I''m doing is when a person selects an item from the
drop down list I select a date in a calendar control and populate a
text box with the date. To do this I set auto postback to the drop
down list. But it always resets the selected index on post back. I
control for this in the onLoad method...

If Not Page.IsPostBack Then

If page is posted back I select the date and populate textbox.text
correctly. Selected index is lost. I even added a key to the
viewstate with the selected index and tried grabbing the value from
that, but still no go. Help please!

推荐答案

下拉列表通常会保持其视图状态，除非您重新绑定它们

他们的数据源。但是我发现如果你的DDL绑定了一个

DataSourceControl，并且你的DDL在另一个控件内（比如在DetailsView的

模板字段中），那么如果你做一些事情，比如更新

detailsview控件中某个字段的headerText，那么它就会重新设置父控件中所有子控件的视图状态。


" Phuff"写道：

Drop down lists do usually maintain their viewstate unless you re-bind them
to their datasource. Howeve i have found that if your DDL is bound to a
DataSourceControl, and your DDL is within another control (such as in a
template field of a DetailsView), then if you do something such as updatting
the headerText of one of the Fields in the detailsview control then it
re-sets the view state of all child controls within parent control.

"Phuff" wrote:

提前致谢！我正在尝试在回发时维护一个dl列表的选定索引
。我正在做的是当一个人从
下拉列表中选择一个项目时，我在日历控件中选择一个日期并用日期填充一个
文本框。为此，我将自动回发设置为下拉列表。但它总是在帖子后面重置选定的索引。我在onLoad方法中对此进行控制...

如果不是Page.IsPostBack那么

如果页面被回发，我选择日期并填充文本框。文字
正确。选定的索引丢失。我甚至用选定的索引向
viewstate添加了一个键，并尝试从
获取值，但仍然没有去。请帮助！

Thanks in advance! I''m trying to maintain a dl list''s selected index
on postback. What I''m doing is when a person selects an item from the
drop down list I select a date in a calendar control and populate a
text box with the date. To do this I set auto postback to the drop
down list. But it always resets the selected index on post back. I
control for this in the onLoad method...

If Not Page.IsPostBack Then

If page is posted back I select the date and populate textbox.text
correctly. Selected index is lost. I even added a key to the
viewstate with the selected index and tried grabbing the value from
that, but still no go. Help please!

谢谢，但不受约束。我所做的是从SQL查询中获取数据集来获取

，然后执行Items.add方法。


我实际上发现它会维护2个选定的州。一个

标记为7和1.第一个索引是描述所有项目的文本字段。

然后我添加其他字段作为数字。该值也设置为

等于字段中作为字符串列出的数字。在我的测试中

例子我有一个字符串......Box / Unit ID然后是1-8的项目。如果我

选择7它将实际保留此索引。其他一切都默认为

1.

Thanks, but its not bound. What I do is loop through dataset grabbed
from a sql query, and then do an Items.add method.

I have actually found that it will maintain 2 selected states. One
labeled 7 and 1. The first index is a text field describing all items.
Then I add the other fields which are numbers. The value is also set
to equal the number listed as a string in the field. OIn my test
example I have a string..."Box/Unit ID" and then an item for 1-8. If I
select 7 it will actually keep this index. Everything else defaults to
1.

为什么不绑定它，然后它会维护ViewState？


" Phuff"写道：

Why not just bind it instead, then it will maintain ViewState?

"Phuff" wrote:

谢谢，但它没有约束。我所做的是从SQL查询中获取数据集，然后执行Items.add方法。

我实际上发现它将保持2个选定的状态。一个标记为7和1的第一个索引是描述所有项目的文本字段。
然后我添加其他字段，这些字段是数字。该值也设置为等于字段中作为字符串列出的数字。在我的测试中
示例我有一个字符串...Box / Unit ID然后是1-8的项目。如果我选择7，它实际上会保留这个索引。其他一切都默认为
1.

Thanks, but its not bound. What I do is loop through dataset grabbed
from a sql query, and then do an Items.add method.

I have actually found that it will maintain 2 selected states. One
labeled 7 and 1. The first index is a text field describing all items.
Then I add the other fields which are numbers. The value is also set
to equal the number listed as a string in the field. OIn my test
example I have a string..."Box/Unit ID" and then an item for 1-8. If I
select 7 it will actually keep this index. Everything else defaults to
1.

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