Hi All,
Just to update all, I figured out the problem. The problem was with the
Employee class. The parameterless constructor was doing nothing, whereas, it
should set the member fields to some default values.. particularly reference
type members such as string members. Since the fields were having value null
the screen was not getting updated. I changed the parameterless constructor
and set the _name and _address members to string.Empty and it started
working!!
Thanks Frans for replying
Regards,
Girish Jain
From: Frans Bouma <[EMAIL PROTECTED]>
Reply-To: "Discussion of advanced .NET topics."
<ADVANCED-DOTNET@DISCUSS.DEVELOP.COM>
To: ADVANCED-DOTNET@DISCUSS.DEVELOP.COM
Subject: Re: [ADVANCED-DOTNET] CurrencyManager and Data Binding
Date: Fri, 2 Jun 2006 19:19:57 +0200
> In the collection class, I am overriding the OnInsertComplete
> method and raising the ListChanged event, with proper args.
You should raise the events yourself.
Like:
public object AddNew()
{
object obj =
Activator.CreateInstance(this._containedType);
BEBase be = (BEBase)obj;
List.Add(be);
return obj;
}
You've to raise the event after teh Add. As you can see with reflector,
OnInsertComplete isn't called when you ADD a method.
(CollectionBase contains an ArrayList internally).
The code looks familiar though ;)
http://weblogs.asp.net/fbouma/articles/115837.aspx
Frans
>
> Although, the entire code was not required still I removed
> certain not required methods and am posting the code. I have
> created custom objects for holding the data and the fields
> are marked with custom attributes. Code goes her.....
>
> using System;
> using System.Collections;
> using System.ComponentModel;
> using System.Runtime.Remoting;
>
> namespace BusinessEntity
> {
> public abstract class BECollection : CollectionBase,
> ITypedList, IBindingList
> {
> protected Type _containedType;
>
> public BECollection( Type t )
> {
> this._containedType = t;
> }
>
> virtual internal int Add( BEBase obj )
> {
> return this.InnerList.Add(obj);
> }
>
> virtual internal void Remove( BEBase obj )
> {
> this.InnerList.Remove(obj);
> }
>
> public BEBase this[int index]
> {
> get
> {
> return InnerList[index];
> }
> set
> {
> List[index] = value;
> }
> }
>
> PropertyDescriptorCollection
> ITypedList.GetItemProperties( PropertyDescriptor[] listAccessors )
> {
> Type typeOfObject = null;
>
> if( (listAccessors==null) ||
> listAccessors.Length==0 )
> {
> typeOfObject = _containedType;
> }
> return this.GetPropertyDescriptors(
> typeOfObject );
> }
>
> string
> ITypedList.GetListName(PropertyDescriptor[] listAccessors)
> {
> return "Learning..";
> }
>
> private PropertyDescriptorCollection
> GetPropertyDescriptors( Type typeOfObject )
> {
> PropertyDescriptorCollection
> typePropertiesCollection = TypeDescriptor.GetProperties(
> typeOfObject );
> ArrayList propertyDescriptorsToUse =
> new ArrayList();
>
> foreach(PropertyDescriptor property
> in typePropertiesCollection)
> {
> BEFieldAttribute befieldAttribute =
>
> (BEFieldAttribute)property.Attributes[typeof(BEFieldAttribute)];
>
> if (befieldAttribute != null)
> {
> // add it, as it has
> the attribute applied to it
>
> propertyDescriptorsToUse.Add(property);
> }
> }
> return new
> PropertyDescriptorCollection((PropertyDescriptor[])propertyDes
criptorsToUse.ToArray(typeof(PropertyDescriptor)));
> }
>
> public void AddIndex(PropertyDescriptor property)
> {
> throw new NotSupportedException();
> }
>
> public bool AllowNew
> {
> get
> {
> return true;
> }
> }
>
> public void ApplySort(PropertyDescriptor
> property, System.ComponentModel.ListSortDirection direction)
> {
> throw new NotSupportedException();
> }
>
> public PropertyDescriptor SortProperty
> {
> get
> {
> throw new NotSupportedException();
> }
> }
>
> public int Find(PropertyDescriptor property,
> object key)
> {
> throw new NotSupportedException();
> }
>
> public bool SupportsSorting
> {
> get
> {
> return false;
> }
> }
>
> public bool IsSorted
> {
> get
> {
> throw new NotSupportedException();
> }
> }
>
> public bool AllowRemove
> {
> get
> {
> return true;
> }
> }
>
> public bool SupportsSearching
> {
> get
> {
> return false;
> }
> }
>
> public
> System.ComponentModel.ListSortDirection SortDirection
> {
> get
> {
> throw new NotSupportedException();
> }
> }
>
> public event
> System.ComponentModel.ListChangedEventHandler ListChanged;
>
> public bool SupportsChangeNotification
> {
> get
> {
> return true;
> }
> }
>
> public void RemoveSort()
> {
> throw new NotSupportedException();
> }
>
> public object AddNew()
> {
> object obj =
> Activator.CreateInstance(this._containedType);
> BEBase be = (BEBase)obj;
>
> List.Add(be);
>
> return obj;
> }
>
> public bool AllowEdit
> {
> get
> {
> return true;
> }
> }
>
> public void RemoveIndex(PropertyDescriptor property)
> {
> throw new NotSupportedException();
> }
>
> protected override void OnInsertComplete(int
> index, object value)
> {
> ListChanged(this, new
> ListChangedEventArgs(ListChangedType.ItemAdded,
> index));
> }
> }
> }
>
>
> Thanks
>
> Regards,
> Girish Jain
>
>
>
>
> >From: Frans Bouma <[EMAIL PROTECTED]>
> >Reply-To: "Discussion of advanced .NET topics."
> ><ADVANCED-DOTNET@DISCUSS.DEVELOP.COM>
> >To: ADVANCED-DOTNET@DISCUSS.DEVELOP.COM
> >Subject: Re: [ADVANCED-DOTNET] CurrencyManager and Data Binding
> >Date: Fri, 2 Jun 2006 12:31:14 +0200
> >
> > > I have created a custom collection class which inherits from
> > > CollectionBase class and implements the IBindingList
> interface. I am
> > > having a problem regarding adding a new record and form binding.
> > > When I add a new record by calling the AddNew() method on the
> > > CurrencyManager class instance, the screen does not get
> refreshed.
> > > When I tried to figure out the problem, I found that the
> position of
> > > the CurrnecyManager does not change, and it does not fire the
> > > PositionChanged event. I figured that the
> > > CurrnecyManager.AddNew() method calls the
> > > IBindingList.AddNew() and it internally calls the
> > > ChangeRecordState() method. By looking at the call stack,
> I see that
> > > the newPosition argument passed to
> > > ChangeRecordState() method is correct and it raises the
> > > CurrentChanged event whereas the PositionChanged event
> does not get
> > > fired and the UI is not updated.
> > >
> > > When I move the record position by incrementing or
> decrementing the
> > > Positon property, the UI controls does get updated
> normally but not
> > > in the case of
> > > AddNew() i.e.
> > >
> > > _cm.Position = _cm.Count-1;
> > >
> > > also does not work
> > >
> > > Your inputs on this would be highly appreciated
> >
> > You should raise ListChanged events in your class.
> You should
> >pass the index of the item changed/ added/ removed as well
> as the type
> >of the change in the eventargs.
> >
> > Frans
> >
> >===================================
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