在 ASP.NET 2.0 中，我们如何检查列表框中的任何项目是否被选中？

Question

I have to do a for loop and check whether any of the items are checked if I want to know if any of the items are checked.

In C#, there is something like

listbox.SelectedItems.Count();

Is there any similar method for ASP.NET?

Answer 1

you can see whether any item is selected by the below code:

if (listboxname.SelectedIndex == -1)
       MessageBox.Show("Please select an Item first!");

Answer 2

看起来你需要遍历它们。

Answer 3

According to MSDN and my experience, you have to go over all the items, to do this:

you can determine the selected item(s) in the ListBox control by enumerating the Items collection and testing the Selected value for each ListItem element.

Answer 4

This might not be available in 2.0 though...but another option is to query the Items collection with LINQ. See this link for info on that

Answer 5

I had the same issue and I may have found a solution for you. I don't know how effective it is. But here it is:

if (listbox.SelectedIndex <= -1)
{
    listbox.SelectedIndex = 0;
}
if (listbox.SelectedIndex > -1)
{
    //do something
}

Answer 6

I had the same issue and I may have found a solution for you. I don't know how effective it is. But here it is:

        if (listData.SelectedIndex>=0)
        {               
                listData.Items.Remove(listData.SelectedItem.ToString());                
        }
        else
        {
            MessageBox.Show("plz select data first");
        }