Introduction
Update to the Magic TabControl to add the ability to allow:
- Change the Tab Title Font
- Change Enable property of a Tab page
- Change Visible property of a Tab page
Background
This is an update to the Magic TabControl
Using the code
In this release of the Magic TabControl, the ability to make Visible a given page as well as Enable a given page is now implemented. The programmer can set the status programmatically as shown in the code sample below.
private void chkVisible_CheckedChanged(object sender, EventArgs e)
{
if (cboTabsInControl.SelectedIndex > -1)
{
((Crownwood.Magic.Controls.TabPage)cboTabsInControl.SelectedItem).Visible = chkVisible.Checked;
}
}
private void chkEnabled_CheckedChanged(object sender, EventArgs e)
{
if (cboTabsInControl.SelectedIndex >-1)
{
((Crownwood.Magic.Controls.TabPage)cboTabsInControl.SelectedItem).Enabled = chkEnabled.Checked;
}
}
Points of Interest
The ability to add this simple mods was straight forward. For the Visibile property, the following enhancement to TabControls.cs was made:
protected virtual void AddTabPage(TabPage page)
{
page.Shown = false;
page.VisibleChanged += new EventHandler(OnPageVisibleChanged);
...
To the AddTabPage function the VisibleChanged event needed to be captured in order to allow a given page to be seen or not to be seen. The OnPageVisibleChanged event will now handle how the tab pages are to be handled when the Visible status changes. In this case, a seperate collection has been created to hold all tab pages set to Visible = false (_tabPagesInVisible). When the Visible = true, the tab page will be searched from the _tabPagesInVisible collection removed and placed back into the _tabPages collection.
protected virtual void OnPageVisibleChanged(object sender,EventArgs e)
{
if (sender is TabPage)
{
if (!((TabPage)sender).Visible)
{
((TabPage)sender).TabIndex = _tabPages.IndexOf((TabPage)sender);
_tabPages.Remove((TabPage)sender);
_tabPagesInVisible.Add((TabPage)sender);
}
else
{
if (_tabPagesInVisible.Count != 0)
{
foreach(TabPage page in _tabPagesInVisible)
{
if (page.Title == ((TabPage)sender).Title)
{
_tabPages.Insert(((TabPage)sender).TabIndex, (TabPage)sender);
_tabPagesInVisible.Remove(page);
break;
}
}
}
}
}
}
Now, since we still want to know what tab pages are truly a part of the tab page control, a mod to the tabPages property was also made, to merge the two data collections.
public virtual TabPageCollection TabPages
{
get {
TabPageCollection allPages = _tabPages;
if (_tabPagesInVisible.Count != 0)
{
foreach(TabPage page in _tabPagesInVisible)
{
allPages.Insert(page.TabIndex, page);
}
}
return allPages;
}
}
The handling of the page.Enabled was a more simple process, again it affected code in the TabControl.cs module
protected virtual void MovePageSelection(TabPage page)
{
int pageIndex = _tabPages.IndexOf(page);
if (pageIndex != _pageSelected && page.Enabled == true)
...
With these simple updates, one can now prevent the user from going into a given tab or simple done't make that tab(s) visible to the user if they do not have rights to access that data.
History
Update to the Magic TabControl to add the ability to allow:
- Change the Tab Title Font
- Change Enable property of a Tab page
- Change Visible property of a Tab page
Working with computers and code since the days of the Fluke 1720A touch control system (1979). A lot of peeks and pokes to get the assembly code in..
Created firmware compilers and optimizers...
These days, life is less complex programming in ASP.NET. Laughing at the arguments of VB.NET vs C#...hmmm, both interpretive, both dependent on the same core...(would hate for those lads who don't get it...to work on the projects that I have prior to ASP.NET)