Today I wrote a simple example which shows how we can use
CollectionEditor of the .NET. In addition to this I also made a simple example which shows how to implement custom
CollectionEditor which allows us to add more than one item to the collection.
Download Example
public class ExampleComponent : Component{
ArrayListCollection _ArrayListItems = new ArrayListCollection();
List<Button> _ListItems = new List<Button>();
List<Control> _MultipleItems = new List<Control>();
public ExampleComponent()
{ }
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[Description("Contains only Control objects in an ArrayList")]
[Category("Behaviour")]
public ArrayListCollection ArrayListItems
{
get { return _ArrayListItems; }
}
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[Description("Contains only Button objects in a List<Button> collection")]
[Category("Behaviour")]
public List<Button> ListItems
{
get { return _ListItems; }
}
// custom editor attribute
[Editor(typeof(CustomCollectionEditor), typeof(UITypeEditor))]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[Description("Contains ListView, Button and CheckBox items in a List<Control> collection")]
[Category("Behaviour")]
public List<Control> MultipleItems
{
get { return _MultipleItems; }
}
public class ArrayListCollection : ArrayList
{
// CollectionEditor searches collection type's Index property and finds its property type.
// It uses this type to add new items
public new Control this[int index]
{
get { return base[index] as Control; }
}
}
// Custom collection editor.
// by using this editor we can add ListView, Button and
// CheckBoxes to the same collection
public class CustomCollectionEditor : CollectionEditor
{
public CustomCollectionEditor()
: base(typeof(List<Control>))
{}
// override this method if you have to do custom initializing
// operations. For example, if you have to use a constructor which
// takes arguments you can create your own items here ...
// or may be you have to do some initializing operations ...
protected override object CreateInstance(Type itemType)
{
if (itemType == typeof(CheckBox))
{
CheckBox checkbox = new CheckBox();
checkbox.Text = "My Text, hede";
return checkbox;
}
Control control = base.CreateInstance(itemType) as Control;
control.Text = "Other, hede";
return control;
}
// if you want to use a custom collection editor form,
// you have to override this method and return your form here
protected override CollectionEditor.CollectionForm CreateCollectionForm()
{
return base.CreateCollectionForm();
}
// here you can return a text which will be appeared in the list
// for the given item
protected override string GetDisplayText(object value)
{
Control control = value as Control;
return string.Format("{0} - {1}", control.GetType().Name, control.Text);
}
// we allow 3 types can be added to our collection
protected override Type[] CreateNewItemTypes()
{
return new Type[] { typeof(ListView), typeof(Button), typeof(CheckBox) };
}
}
}
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