Cannot Cast from ListViewSubItem

[Randal Chapman]

Hi.

I have a custom class which inherits from
ListViewItem.ListViewSubItem.

It works fine to add new subitems to a listview, but when I try and
get them out it tells me that it is an invalid cast. So, it let me add
the custom item but won't let me get it back out? What's wrong here?
Could it have something to do with the fact that the ListViewSubItem
is a subclass?

sViewSubItem = new CustListViewSubItem();
sViewSubItem = (CustListViewSubItem)sViewItem.SubItems;

_Randal

 

[Chuck]

Hi.

I have a custom class which inherits from
ListViewItem.ListViewSubItem.

It works fine to add new subitems to a listview, but when I try and
get them out it tells me that it is an invalid cast. So, it let me add
the custom item but won't let me get it back out? What's wrong here?
Could it have something to do with the fact that the ListViewSubItem
is a subclass?

sViewSubItem = new CustListViewSubItem();
sViewSubItem = (CustListViewSubItem)sViewItem.SubItems;

_Randal

What type does the watch window say the subitem is? Even if a class is cast
to a base class the watch will correctly ID the correct class.

Chuck

 

[Randal Chapman]

Hi.

I have a custom class which inherits from
ListViewItem.ListViewSubItem.

It works fine to add new subitems to a listview, but when I try and
get them out it tells me that it is an invalid cast. So, it let me add
the custom item but won't let me get it back out? What's wrong here?
Could it have something to do with the fact that the ListViewSubItem
is a subclass?

sViewSubItem = new CustListViewSubItem();
sViewSubItem = (CustListViewSubItem)sViewItem.SubItems;

_Randal

What type does the watch window say the subitem is? Even if a class is cast
to a base class the watch will correctly ID the correct class.

Chuck

It's a ListViewItem.ListViewSubItem like it's supposed to be. Try it,
it just doesn't seem to work for some reason.

_Randal

 

[Chris Jobson]

Hi.

I have a custom class which inherits from
ListViewItem.ListViewSubItem.

It works fine to add new subitems to a listview, but when I try and
get them out it tells me that it is an invalid cast. So, it let me add
the custom item but won't let me get it back out? What's wrong here?
Could it have something to do with the fact that the ListViewSubItem
is a subclass?

sViewSubItem = new CustListViewSubItem();
sViewSubItem = (CustListViewSubItem)sViewItem.SubItems;

_Randal

What type does the watch window say the subitem is? Even if a class is
cast
to a base class the watch will correctly ID the correct class.

Chuck

It's a ListViewItem.ListViewSubItem like it's supposed to be. Try it,
it just doesn't seem to work for some reason.

_Randal

It worked fine for me, BUT only after I remembered that the first sub-item
is index 1 and NOT index 0 (which actually returns the item that owns the
subitems). If i has the value 0 in your example code then that explains the
invalid cast exception.

Chris Jobson

 

[Chuck]

Hi.

I have a custom class which inherits from
ListViewItem.ListViewSubItem.

It works fine to add new subitems to a listview, but when I try and
get them out it tells me that it is an invalid cast. So, it let me add
the custom item but won't let me get it back out? What's wrong here?
Could it have something to do with the fact that the ListViewSubItem
is a subclass?

sViewSubItem = new CustListViewSubItem();
sViewSubItem = (CustListViewSubItem)sViewItem.SubItems;

_Randal

What type does the watch window say the subitem is? Even if a class is
cast
to a base class the watch will correctly ID the correct class.

Chuck

It's a ListViewItem.ListViewSubItem like it's supposed to be. Try it,
it just doesn't seem to work for some reason.

_Randal

Try this for a general 'catcher'

private void listView1_SelectedIndexChanged(object sender, System.EventArgs
e)
{
ListViewItem lvi = listView1.SelectedItems[0];
for(int i=0; i< lvi.SubItems.Count; i++)
{
if(lvi.SubItems is CustListViewSubItem)
{
DoCustThings();
}
else if(lvi.SubItemsis ListViewItem.ListViewSubItem)
{
DoBaseThings();
}
}
}

Chuck

 

[Randal Chapman]

It worked fine for me, BUT only after I remembered that the first sub-item
is index 1 and NOT index 0 (which actually returns the item that owns the
subitems). If i has the value 0 in your example code then that explains the
invalid cast exception.

Chris Jobson

DUH!!! I cannot believe I didn't think of that! Thanks man, it works fine now.

_Randal