Contains Method and IndexOf Method seem not work in Compact Framew

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Machi - 28 Apr 2005 08:36 GMT

May i know why the Contains Method always return false and IndexOf method
always return -1 although the value for "cboTableIDMain.Text.Trim())" is the
same?

Thanks you very much.
==================================================
ListViewItem lsvItem = new ListViewItem(cboTableIDMain.Text.Trim());
int index = lsvTableList.Items.IndexOf(lsvItem);
bool bln = lsvTableList.Items.Contains(lsvItem);

if (lsvTableList.Items.IndexOf(lsvItem) < 0)
{
    lsvTableList.BeginUpdate();
    lsvTableList.Items.Add(lsvItem);
    lsvTableList.EndUpdate();
}

===================================================

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Christof Nordiek - 28 Apr 2005 09:42 GMT

Hi Machi,

simply calling new ListViewItem(...) doesn't put the new item to
lsvTableIDMain.
You have to call lsvTableList.Items.Add(lsv); after the first line.

> May i know why the Contains Method always return false and IndexOf method
> always return -1 although the value for "cboTableIDMain.Text.Trim())" is
[quoted text clipped - 15 lines]
>
> ===================================================

Reply to this Message

Machi - 28 Apr 2005 10:36 GMT

I do not get what you mean. Do you see the source codes properly? I
understand that new ListViewItem(...) doesn't put the new item to the
ListView control and i don't want to put the data into listview control until
i make sure the text i want to put it in the listview control is not
available in the listview control.

I want to make sure there is no duplication of same text in the listview
control.

I, for sure can use looping to check for that, but besides that, is there
any better way to do so?

Thanks.

> Hi Machi,
>
[quoted text clipped - 21 lines]
> >
> > ===================================================

Reply to this Message

Morten Wennevik - 28 Apr 2005 10:27 GMT

Hi Machi,

You are testing if a ListViewItem reference is already inside your ListView, not the contents of the ListViewItem.

Since you create a new ListViewItem it will have a new reference and will never be found. Contains/IndexOf will therefore always fail.

Try something like this

string s = cboTableIDMain.Text.Trim();
bool found = false;
foreach(ListViewItem lvi in lsvTableList.Items)
{
    if(lvi.Text == s)
    {
        found = true;
        break;
    }
}
if(!found)
    lsvTableList.Items.Add(new ListViewItem(s));

> May i know why the Contains Method always return false and IndexOf method
> always return -1 although the value for "cboTableIDMain.Text.Trim())" is the
[quoted text clipped - 14 lines]
>
> ===================================================

Signature

Happy coding!
Morten Wennevik [C# MVP]

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Machi - 28 Apr 2005 10:42 GMT

Morten Wennevik, thanks for the information.

> Hi Machi,
>
[quoted text clipped - 35 lines]
> >
> > ===================================================

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Contains Method and IndexOf Method seem not work in Compact Framew

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