Question

I have a ListView which has checkboxes on the first column. While writing some code for a custom sort (when the user clicks the column header) I’ve come across some weird behavior.

When the user clicks a column header, I’m using a ColumnClickEventHandler to set listView.Sorting to SortOrder.Ascending (or SortOrder.Descending); when this line of code gets hit, it seems to fire off the ItemCheck event handler.

eg

listView.ItemCheck += new ItemCheckEventHandler(listView_ItemCheck);
listView.ColumnClick += new ColumnClickEventHandler(listView_ColumnClick);
...
...
void listView_ColumnClick(object sender, ColumnClickEventArgs e)
{
   // Determine whether the column is the same as the last column clicked.
   if (e.Column != sortColumn)
   {
      // Set the sort column to the new column.
      sortColumn = e.Column;
      // Set the sort order to ascending by default.
      listView.Sorting = SortOrder.Ascending;
   }
   else
   {
      // Determine what the last sort order was and change it.
      if (listView.Sorting == SortOrder.Ascending)
         listView.Sorting = SortOrder.Descending;
      else
         listView.Sorting = SortOrder.Ascending;
   }
}

After the line listView.Sorting = SortOrder.Descending; is hit the event handler for listView.ItemCheck is called.

Answer 1

this is probably a bad trick, but you could try :

void listView_ColumnClick(object sender, ColumnClickEventArgs e)
{
   listView.ItemCheck -= listView_ItemCheck;
   // Determine whether the column is the same as the last column clicked.
   if (e.Column != sortColumn)
   {

      // Set the sort column to the new column.
      sortColumn = e.Column;
      // Set the sort order to ascending by default.
      listView.Sorting = SortOrder.Ascending;
   }
   else
   {
      // Determine what the last sort order was and change it.
      if (listView.Sorting == SortOrder.Ascending)
         listView.Sorting = SortOrder.Descending;
      else
         listView.Sorting = SortOrder.Ascending;

   } 
   listView.ItemCheck += listView_ItemCheck;
}

or

use a boolean property (private bool disableItemCheck_) used in

listView_ColumnClick (same place as my modifications) and

listView_ItemCheck 

if (disableItemCheck_)
return;
//ItemCheck logic