WPF: Control Visibility from Database / Prerender Hook
we have a rather odd requirement: The visibility of any control in our WPF-Application is to be driven by a database-table.
That means we have a table which stores the name of the element and its visiblity.
Now I am looking for an elegant way to implement this feature on the client side.
I could create my 开发者_如何学运维own UserControl and inherit from it everywhere, providing a InitializeComponent Template Method. But what if someone programmatically adds more childcontrols?
I don't want my controls to know about this mechanism at all. I want to hook in/intercept at a certain point (pre control-rendering) and adjust the visibility of the control according to the database.
Is that somehow possible? And if not, how would you design it?
So here is what I did:
I inherited from UserControl and put the check in the an EventHandler for the Loaded Event.
I then let my Controls inherit from my CustomControl, this works pretty well.
The FindName() implementation won't find the FrameworkElements for some reason I don't know, although their names are defined in the xaml. So here is the routine I use to find the children by their names:
public static T FindVisualChildByName<T>(DependencyObject parent, string name) where T : DependencyObject
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
string controlName = child.GetValue(Control.NameProperty) as string;
if (controlName == name)
{
return child as T;
}
else
{
T result = FindVisualChildByName<T>(child, name);
if (result != null)
{
return result;
}
}
}
return null;
}
I don't like this solution but it works.
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