Add MenuItems to a ContextMenuStrip from SubItems of a ListView

Question

My Form defines a ContextMenuStrip:

Dim CMS As New ContextMenuStrip
Button1.ContextMenuStrip = CMS

There is also a Listview with 5 columns and some data:

ListView1.View = View.Details

How can I display the content of SubItems at index 1 and K of the first 5 Items of this ListView in a ContextMenuStrip?

CMS.Items.Clear()
For i As Integer = 0 To 5
    Dim line As String = ListView1.Items(i).SubItems(1).Text
    Dim line1 As String = ListView1.Items(i).SubItems(3).Text
    CMS.Items.Add(line & "|" & line1)
Next i

If the ListView contains are less than 5 ListViewItems, I get an exception.
If there is one ListViewItem in the ListView, then create one MenuItem.
If there are more than 5 ListViewItems, then display only values from the first 5 Items.

Jimi · Answer 1 · 2021-08-03T13:02:52.747

You can define an interval of values in different ways.
Using the Min/Max methods of the Math class is probably simple and it can adapted to different scenarios. Personally, I used it quite often to validate the Maximum and Minimum values of Properties (e.g., you have a Property of Type Byte, so you may want to accept only values between 0 and 255).

You want to retrieve values from SubItems of the first 5 Items of a ListView. This is the Max() value.
The Min number of elements is determined by the content of the Items collection. It could be 0: in this case we don't want to iterate that collection, since it has nothing to give back. So, 0 is the Min() value
We need to consider that the indexer of these collections starts from 0.

The range of values is then:

Math.Max(Math.Min([Items Number], 5), 0) - 1

-1 since we start from 0: if we want Max 5 values, we iterate from 0 to (5 - 1) and if the Items collection has 0 elements, we iterate from 0 to (0 - 1), so we don't iterate the collection at all (the loop terminates right away).

You can rewrite your loop as:

For i As Integer = 0 To Math.Max(Math.Min(ListView1.Items.Count, 5), 0) - 1
    Dim line As String = ListView1.Items(i).SubItems(1).Text
    Dim line1 As String = ListView1.Items(i).SubItems(3).Text
    CMS.Items.Add(line & "|" & line1)
Next i

You asked to get the **first** 5 Items: your question was *If there are more than 5 lines, then display only the first 5 lines*. — Jimi, Aug 03 '21 at 14:07

Add MenuItems to a ContextMenuStrip from SubItems of a ListView

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