Until now, I use the Xceed propertygrid with AutoGenerateProperties="True" and specify which properties I don't want to display by using the [Browsable(false)] attribute.
Now I have a case, where I need to show only a subset of properties, depending on the value of an other property.
I think the answer is to use PropertyDefinitions, as shown here.
But the example only shows how to implement a single set of PropertyDefinitions that will be used for every inspected object.
Do you have a hint or an example of how I can define multiple sets of PropertyDefinitions and choose when they should be used?
Sorry this is quite a lengthy answer. I also used to use AutoGenerateProperties="True" however I had a similar issue.
My resulting solution was to populate the PropertyDefinition as you suggested. I did this programmatically as I ended up having some rather special cases with wanting properties created dynamically based on the contents of a collection somewhere. One thing I did notice was that even through programmatically checking through my classes to emulate the AutoGenerateProperties="True" feature mine was much faster than their solution.
In order to deal with the Visibility as you requested though I had to create my own Attribute to make items invisible from the PropertyGrid.
public class VisibilityAttribute : Attribute
{
public Visibility Visibility { get; private set; }
public VisibilityAttribute(Visibility visibility)
{
this.Visibility = visibility;
}
}
Each item that can be selected in my project has it's own implementation of a PropertySetBase class that has property definitions like so:
[Category("Appearance"), LocalisedProperty(typeof(PropertySetBase), "LocalBackground", "LocalBackgroundDescription"), Editor(typeof(OptionalBrushEditor), typeof(OptionalBrushEditor)),
PropertyOrder(0)]
public virtual OptionalProperty<Brush> LocalBackground { get; set; }
And the logic to then process the PropertySetBases in the currentPropertySelection collection.
private void PreparePropertyGrid()
{
PropertyDefinitionCollection propertyDefinitions = new PropertyDefinitionCollection();
// This is how I determine
var mainPropertySet = this.currentPropertySelection.FirstOrDefault();
if (mainPropertySet != null)
{
var properties = TypeDescriptor.GetProperties(mainPropertySet.GetType());
// Allowing for multiple selection, if on further iterations through the selected items we will remove properties that do not exist in both PropertySets
bool firstIteration = true;
foreach (var x in this.currentPropertySelection)
{
foreach (var p in properties.Cast<PropertyDescriptor>())
{
if (!firstIteration)
{
// Perhaps we should be checking a little more safely for TargetProperties but if the collection is empty we have bigger problems.
var definition = propertyDefinitions.FirstOrDefault(d => string.Equals(d.TargetProperties[0] as string, p.Name, StringComparison.Ordinal));
// Someone in the selection does not have this property so we can ignore it.
if (definition == null)
{
continue;
}
// If this item doesn't have the property remove it from the display collection and proceed.
var localProperty = x.GetType().GetProperty(p.Name);
if (localProperty == null)
{
propertyDefinitions.Remove(definition);
continue;
}
// There is actually no point in proceeding if this is not the first iteration and we have checked whether the property exists.
continue;
}
string category = p.Category;
string description = p.Description;
string displayName = p.DisplayName ?? p.Name;
int? displayOrder = null;
bool? isBrowsable = p.IsBrowsable;
bool? isExpandable = null;
var orderAttribute = p.Attributes[typeof(PropertyOrderAttribute)] as PropertyOrderAttribute;
if (orderAttribute != null)
{
displayOrder = orderAttribute.Order;
}
var expandableAttribute = p.Attributes[typeof(ExpandableObjectAttribute)] as ExpandableObjectAttribute;
if (expandableAttribute != null)
{
isExpandable = true;
}
propertyDefinitions.Add(new PropertyDefinition
{
Category = category,
Description = description,
DisplayName = displayName,
DisplayOrder = displayOrder,
IsBrowsable = isBrowsable,
IsExpandable = isExpandable,
TargetProperties = new[] { p.Name },
});
}
}
firstIteration = false;
this.propertyGrid.PropertyDefinitions = propertyDefinitions;
}
}
When it came to actually showing/hiding the properties I did the following:
public void UpdateProperties(Tuple<string, bool?, Visibility?>[] newPropertyStates)
{
// Note this currently works under the assumption that an Item has to be selected in order to have a value changed.
this.suppressPropertyUpdates = true;
foreach (var property in newPropertyStates)
{
string propertyName = property.Item1;
string[] splits = propertyName.Split('.');
if (splits.Length == 1)
{
this.propertyGrid.Properties.OfType<PropertyItem>()
.Where(p => string.Equals(p.PropertyDescriptor.Name, propertyName, StringComparison.Ordinal))
.Map(p =>
{
if (property.Item2.HasValue)
{
p.IsEnabled = property.Item2.Value;
}
if (property.Item3.HasValue)
{
p.Visibility = property.Item3.Value;
}
});
}
else // We currently don't expect to go any lower than 1 level.
{
var parent = this.propertyGrid.Properties.OfType<PropertyItem>()
.Where(p => string.Equals(p.PropertyDescriptor.Name, splits[0], StringComparison.Ordinal))
.FirstOrDefault();
if (parent != null)
{
parent.Properties.OfType<PropertyItem>()
.Where(p => string.Equals(p.PropertyDescriptor.Name, splits[1], StringComparison.Ordinal))
.Map(p =>
{
if (property.Item2.HasValue)
{
p.IsEnabled = property.Item2.Value;
}
if (property.Item3.HasValue)
{
p.Visibility = property.Item3.Value;
}
});
}
}
}
this.suppressPropertyUpdates = false;
}
Then inside the PreparePropertyItem event handler I check for my VisibilityAttribute and update the property item accordingly.
void PropertyGrid_PreparePropertyItem(object sender, PropertyItemEventArgs e)
{
foreach (var x in this.currentPropertySelection)
{
// If we are in read-only mode do not allow the editing of any property.
if (this.IsReadOnly)
{
e.PropertyItem.IsEnabled = false;
}
string propertyName = ((PropertyItem)e.PropertyItem).PropertyDescriptor.Name;
PropertyInfo property = x.GetType().GetProperty(propertyName);
var propertyItem = e.Item as PropertyItem;
// If the property doesn't exist then check to see if it is on an expandable item.
if (property == null)
{
property = propertyItem.Instance.GetType().GetProperty(propertyName);
}
bool hasProperty = property != null;
if (hasProperty)
{
var browsableAttribute = property.GetCustomAttribute<BrowsableAttribute>(true);
if (browsableAttribute != null &&
!browsableAttribute.Browsable)
{
e.PropertyItem.Visibility = Visibility.Collapsed;
e.Handled = true;
break;
}
var visibilityAttribute = property.GetCustomAttribute<VisibilityAttribute>(true);
if (visibilityAttribute != null)
{
e.PropertyItem.Visibility = visibilityAttribute.Visibility;
e.Handled = true;
}
var independentAttribute = property.GetCustomAttribute<IndependentAttribute>(true);
// If a property is marked as being independent then we do not allow editing if multiple items are selected
if (independentAttribute != null &&
this.currentPropertySelection.Length > 1)
{
e.PropertyItem.IsEnabled = false;
e.Handled = true;
break;
}
}
}
}