Listview: add new row

[donkeyparfait]

I am writing code to display in a listview. I have used a For/Next loop that should add a new line in the listview each time it loops. All i get now is one line when i execute the code. I tested the loop by sending the output to a message box and it showed a message box for every loop. So the loop works, but it is not displaying it in the listview correctly. I think I am missing something that would make the loop process go to the next row in the listview. Here is the code i have so far.

Dim intMultiplicand, intMultiplier, intProduct As Integer
Dim lviTable As New ListViewItem
Const strX = "X"
Const strEquals = "="
Dim objForm1 As New Form1

intMultiplicand = 1
intMultiplier = 1
For intMultiplicand = 1 To 12
intProduct = intMultiplicand * intMultiplier
lviTable.SubItems.Add(intMultiplicand)
lviTable.SubItems.Add(strX)
lviTable.SubItems.Add(intMultiplier)
lviTable.SubItems.Add(strEquals)
lviTable.SubItems.Add(intProduct)

For intMultiplier = 1 To 12
intProduct = intMultiplicand * intMultiplier
lviTable.SubItems.Add(intMultiplicand)
lviTable.SubItems.Add(strX)
lviTable.SubItems.Add(intMultiplier)
lviTable.SubItems.Add(strEquals)
lviTable.SubItems.Add(intProduct)

Next intMultiplier
Next intMultiplicand

lstTable.Items.Add(lviTable)

Please help.

[Killer42]

I'm not that familiar with the listview, so don't take anything I say too seriously. But it looks to me as though all you're doing in these loops is adding lots of subitems (which I believe are equivalent to "columns") into one row.

I didn't really follow the code very well, but if you're expecting multiple rows, then wouldn't I expect to find the Items.Add inside the loop(s)?

(I must have a different version of the listview control here, as it doesn't even have .Items - it has .ListItems. So I may be talking complete garbage. :))

[donkeyparfait]

I'm not that familiar with the listview, so don't take anything I say too seriously. But it looks to me as though all you're doing in these loops is adding lots of subitems (which I believe are equivalent to "columns") into one row.

I didn't really follow the code very well, but if you're expecting multiple rows, then wouldn't I expect to find the Items.Add inside the loop(s)?

(I must have a different version of the listview control here, as it doesn't even have .Items - it has .ListItems. So I may be talking complete garbage. :))

Good point. The loop is not adding any new Items. The assignment requires the subitems, but you are right. I need something that will add Items in the loop. Thanks. This gives me something to work with now. I have been staring at this code all weekend. You guys are great!

[donkeyparfait]

Good point. The loop is not adding any new Items. The assignment requires the subitems, but you are right. I need something that will add Items in the loop. Thanks. This gives me something to work with now. I have been staring at this code all weekend. You guys are great!

BTW,

The code is supposed to produce the multiplication table throught the 12's in the listview. It should look like this...

1 X 1 = 1
1 X 2 = 2
1 X 3 = 3

There should be 144 Items when it is finished, and it should all populate at the touch of one button.

[Killer42]

Hm... in that case, could you see whether this works?

Dim intMultiplicand, intMultiplier, intProduct As Integer
Dim lviTable As New ListViewItem
Const strX = "X"
Const strEquals = "="
' Dim objForm1 As New Form1
 
' intMultiplicand = 1
' intMultiplier = 1
For intMultiplicand = 1 To 12
  ' intProduct = intMultiplicand * intMultiplier
  ' lviTable.SubItems.Add(intMultiplicand)
  ' lviTable.SubItems.Add(strX)
  ' lviTable.SubItems.Add(intMultiplier)
  ' lviTable.SubItems.Add(strEquals)
  ' lviTable.SubItems.Add(intProduct)
  For intMultiplier = 1 To 12
 
    ' Somehow clear/reset lviTable. I don't know how.
 
    intProduct = intMultiplicand * intMultiplier
    lviTable.SubItems.Add (intMultiplicand)
    lviTable.SubItems.Add (strX)
    lviTable.SubItems.Add (intMultiplier)
    lviTable.SubItems.Add (strEquals)
    lviTable.SubItems.Add (intProduct)
    lstTable.Items.Add (lviTable)
  Next intMultiplier
Next intMultiplicand
 

[donkeyparfait]

I was thinking the same thing, but I got this error when I tried that.

An unhandled exception of type 'System.ArgumentException' occurred in system.windows.forms.dll

Additional information: Cannot add or insert the item '' in more than one place. You must first remove it from its current location or clone it.

What does that mean?

[donkeyparfait]

Now I am getting 144 Items, but it is not displaying the subitems. Here is what I have changed.

  Dim intMultiplicand, intMultiplier, intProduct As Integer
        Dim lviTable As New ListViewItem
        Const strX = "X"
        Const strEquals = "="
        Dim objForm1 As New Form1
 
        intMultiplier = 1
        For intMultiplicand = 1 To 12
            lstTable.Items.Add(intMultiplicand)          
           intProduct = intMultiplicand * intMultiplier
            lviTable.SubItems.Add(strX)
            lviTable.SubItems.Add(intMultiplier)
            lviTable.SubItems.Add(strEquals)
            lviTable.SubItems.Add(intProduct)
            For intMultiplier = 2 To 12
                lstTable.Items.Add(intMultiplicand)
                intProduct = intMultiplicand * intMultiplier
                lviTable.SubItems.Add(strX)
                lviTable.SubItems.Add(intMultiplier)
                lviTable.SubItems.Add(strEquals)
                lviTable.SubItems.Add(intProduct)
 
            Next intMultiplier
        Next intMultiplicand
 
        lstTable.Items.Add(lviTable)

[Killer42]

I was thinking the same thing, but I got this error when I tried that.

An unhandled exception of type 'System.ArgumentException' occurred in system.windows.forms.dll
Additional information: Cannot add or insert the item '' in more than one place. You must first remove it from its current location or clone it.

What does that mean?

I think that means you tried to add two items with the same index. To me, that sounds as though you are heading in the right direction - after all, at least you are trying to add more than one item. :)

You might try just plugging in some unique string (Eg. the two numbers concatenated) as the index, and see what happens. I wish I had more experience with the listview...

[donkeyparfait]

You have been a great help. At least I am getting new results now. Thanks.

[senthilk111]

hello, you just trying load mutiplication table in the listview. In vb 6.0 no need to new operator for listview. and please surf in msdn for listview in vb 6.0 you get good description.

if you have any doubt in that example you can query me

[Killer42]

And make sure you let us know here, how things turn out. :)

[donkeyparfait]

THAT WAS IT!!!!!!! You can add subItems without declaring a variable for the ListViewItems. Here is the solution:

 Private Sub btnMultiply_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnMultiply.Click
        Dim intMultiplicand, intMultiplier, intProduct As Integer
        Const strX = "X"
        Const strEquals = "="
        Dim objForm1 As New Form1
        Dim intCount As Integer
 
 
        intCount = 0       
            For intMultiplicand = 1 To 12
            intMultiplier = 1
            lstTable.Items.Add(intMultiplicand)
            intProduct = intMultiplicand * intMultiplier
            lstTable.Items(intCount).SubItems.Add(strX)
            lstTable.Items(intCount).SubItems.Add(intMultiplier)
            lstTable.Items(intCount).SubItems.Add(strEquals)
            lstTable.Items(intCount).SubItems.Add(intProduct)
            intCount += 1
            For intMultiplier = 2 To 12
                lstTable.Items.Add(intMultiplicand)
                intProduct = intMultiplicand * intMultiplier
                lstTable.Items(intCount).SubItems.Add(strX)
                lstTable.Items(intCount).SubItems.Add(intMultiplier)
                lstTable.Items(intCount).SubItems.Add(strEquals)
                lstTable.Items(intCount).SubItems.Add(intProduct)
                intCount += 1           
             Next intMultiplier
        Next intMultiplicand 

I added a count in the loop that would add one every loop so i could tell the listview where to place the Item and SubItem. Then I changed my lsvTable.SubItems.Add() to lstTable.Items(intCount).SubItems.Add. I'm not sure if i explained this correctly, but THANK YOU GUYS VERY MUCH. IT WORKED.

[Killer42]

Excellent!

It's good to see you've resolved your problem.