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XamGrid - How to handle Checked/Unchecked events of the checkboxes in a CheckBoxColumn
posted

Hello,

first of all a "Happy New Year" to the support team!

I need to know the best way how to attach event handler to the CheckBox of a CheckBoxColumn for handling Checked/Unchecked events.

Up to now we attached the event handler in the event handler for CellControlAttached:

private void levelXamGrid_CellControlAttached(object sender, CellControlAttachedEventArgs e)
{
    if (((Infragistics.Controls.Grids.CellBase)e.Cell).Column is Infragistics.Controls.Grids.CheckBoxColumn)
    {
        System.Diagnostics.Trace.WriteLine("ProhibitionControl - levelXamGrid_CellControlAttached");

        (e.Cell.Control.Content as System.Windows.Controls.CheckBox).Checked += ProhibitionControl_Checked;
        (e.Cell.Control.Content as System.Windows.Controls.CheckBox).Unchecked += ProhibitionControl_Unchecked;
    }
}

At the moment the Checked/Unchecked event handler only do some Trace output:

void ProhibitionControl_Checked(object sender, RoutedEventArgs e)
{
    System.Diagnostics.Trace.WriteLine("ProhibitionControl - ProhibitionControl_Checked");
}

void ProhibitionControl_Unchecked(object sender, RoutedEventArgs e)
{
    System.Diagnostics.Trace.WriteLine("ProhibitionControl - ProhibitionControl_UnChecked");
}


The grid layout is set up in the following method:

private bool CreateGridLayout(XamGrid gridTable)
{
    if (Levels1 == null || Levels1.Count == 0 || Levels2 == null || Levels2.Count == 0)
    {
        return false;
    }

    // Create the Grid-Layout
    gridTable.Columns.Clear();
    gridTable.ItemsSource = null;
    gridTable.HeaderRowHeight = RowHeight.Dynamic;

    TextColumn col = new TextColumn();
    col.Key = "Name";
    col.HeaderText = "Name";
    gridTable.Columns.Add(col);
    foreach (CCJLevel level2 in Levels2)
    {
        CheckBoxColumn chckcol = new CheckBoxColumn();
        chckcol.Key = "lev" + level2.ID.ToString();
        chckcol.HeaderText = level2.Name;
       
        chckcol.EditorDisplayBehavior = EditorDisplayBehaviors.Always;
        gridTable.Columns.Add(chckcol);
    }

    return true;
}

When initializing the grid, you can see in the attached file 'ProhibXamGridWithCheckBoxColumn.PNG', I get the following Trace output:

ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached

'ProhibitionControl - levelXamGrid_CellControlAttached' is traced 12 times because the grid contains 12 Checkboxes.
'ProhibitionControl - ProhibitionControl_Checked' is traced 11 times because 11 Checkboxes are checked.
In this case the behavior is correct.

If I then check the last unchecked Checkbox I get the following Trace output:

ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_ActiveCellChanged

In this case the behavior is not correct, because I would expect only one Trace output for 'ProhibitionControl - ProhibitionControl_Checked'.

If I then uncheck the last checked Checkbox again I get the following Trace output:

ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_Click

In this case the behavior is not correct, because I would expect only one Trace output for 'ProhibitionControl - ProhibitionControl_UnChecked'.

If I then uncheck the first checked Checkbox I get the following Trace output:

ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_Click
ProhibitionControl - ProhibitionControl_UnChecked
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - levelXamGrid_CellControlAttached
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - ProhibitionControl_Checked
ProhibitionControl - levelXamGrid_ActiveCellChanged

In this case the behavior is not correct, because I would expect only one Trace output for 'ProhibitionControl - ProhibitionControl_UnChecked'.

My questions:
1. What is the best way to handle the case, when the selection of a CheckBox changes?
2. Do we really need two event handler for Checked/Unchecked events?
3. How should we attach the event handler for Checked/Unchecked events?
4. How can we achieve that the specific handler is called only once when the selection (respectively the check state) of a CheckBox changes?

Please open the attached file 'ProhibXamGridWithCheckBoxColumn.PNG'.

Regards,
chrisobs

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