检查的最佳方式,如果一个下拉列表中包含的价值? [英] Best way to check if a drop down list contains a value?
问题描述
当用户导航到一个新的页面,这DDL的选择指数是由一个cookie确定,但如果DDL不包含cookie的值,那么我想它被设置为0。用什么方法将我用于DDL?是循环的最佳方式,或者是有一个简单的if语句我能执行?
这是我所尝试,但它不返回一个bool。
如果(!ddlCustomerNumber.Items.FindByText(GetCustomerNumberCookie()的ToString()))
ddlCustomerNumber.SelectedIndex = 0;
有两种方法浮现在脑海中:
您可以使用包含像这样:
如果(ddlCustomerNumber.Items.Contains(新
列表项(GetCustomerNumberCookie()的ToString())))
{
// ... code在这里
}
或修改当前的策略:
如果(ddlCustomerNumber.Items.FindByText(
GetCustomerNumberCookie()的ToString())!= NULL)
{
// ... code在这里
}
编辑:还有一个 DropDownList.Items.FindByValue
除了将搜索基于价值观的工作方式FindByText一样的,而不是
When the user navigates to a new page, this ddl's selected index is determined by a cookie, but if the ddl doesn't contain that cookie's value, then I'd like it to be set the 0. What method would I use for the ddl? Is a loop the best way, or is there a simply if statement I can perform?
This is what I've attempted, but it doesn't return a bool.
if ( !ddlCustomerNumber.Items.FindByText( GetCustomerNumberCookie().ToString() ) )
ddlCustomerNumber.SelectedIndex = 0;
There are two methods that come to mind:
You could use Contains like so:
if (ddlCustomerNumber.Items.Contains(new
ListItem(GetCustomerNumberCookie().ToString())))
{
// ... code here
}
or modifying your current strategy:
if (ddlCustomerNumber.Items.FindByText(
GetCustomerNumberCookie().ToString()) != null)
{
// ... code here
}
EDIT: There's also a DropDownList.Items.FindByValue
that works the same way as FindByText, except it searches based on values instead.
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