Infralution Support

[mouse9]

I need to enable and disable individual cells, Windows style (disabled = grayed and doesn't respond) The column is boolean (checkbox). The Editable property of CellWidget has no effect. Below is what I have tried in a class derived from VirtualTree, which sort of works but the checkbox controls disappear in some rows and appear sometimes on a row after the last row. Is there a better/correct way to do this? Thanks

private void EnableCheckBoxColumn(bool enabled)
{
Column column = GetColumnByName("ShowROI");
if (column == null)
return;

int i = 0;
Row row = GetRow(i);
while (row != null)
{
CellWidget cellWidget = GetCellWidget(row, column);
if (cellWidget != null)
{
Control control = cellWidget.EditorControl;
if (control != null)
{
control.Enabled = enabled;
}
}

row = GetRow(++i);
}
}

private void EnableCheckBox(RoiAnalysis roi, bool enabled)
{
Column column = GetColumnByName("ShowROI");
Row row = FindRow(roi);

if (column != null && row != null)
{
CellWidget cellWidget = GetCellWidget(row, column);
if (cellWidget != null)
{
Control control = cellWidget.EditorControl;
if (control != null)
{
control.Enabled = enabled;
}
}
}
}

[Infralution]

Because VirtualTree is data driven and creates editor controls dynamically the approach you have taken to try and enumerate over the currently visible editor controls is likely to have problems.

The correct way to do this is to handle the InitializeControl event of the CellEditor. Then set the Control enabled to true or false based on some properties of the data in the row (or cell). The code below assumes you have some method "CanEdit" that returns true or false depending on whether the control should be enabled for that data item.

[mouse9]

This works only if the rows affected by changes to the underlying data are not visible in the control (ie scrolled out of visible range). Visible rows do not update their enabled state. I am calling UpdateRows() immediately after changing the underlying data.

[Infralution]

Yes you are right - I didn't realize you wanted to change the enabled state dynamically. Instead of handling the InitializeControl event you can handle the SetValue event like below: