WPF cascaded combo

[bindum31]

Hi, I am using LINQ to SQL and MVVM pattern in my application where i am retrieving my data by the following query:

internal ObservableCollection GetCategoryList()
{
DataLoadOptions dataLoadOptions = new DataLoadOptions();
dataLoadOptions.LoadWith(t => t.INVSubCategories);
this.Context.LoadOptions = dataLoadOptions;

 var categories = from category in this.Context.INVCategories
                  orderby category.CatgeoryId descending
                  select category;
 return new ObservableCollection(categories.ToList());

}

And my XAML code for parent(Category) combo is:

<ComboBox Grid.Column="1" Grid.Row="0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="0,2,10,2" TabIndex="0" x:Name="categoryComboBox"
ItemsSource="{Binding CategoryList}" IsEditable="True" DisplayMemberPath="CategoryName" SelectedValuePath="CatgeoryId" SelectedItem="{Binding CategoryList, Mode=TwoWay}" SelectedValue="{Binding Path=CurrentEntity.CategoryId, Mode=TwoWay}" >
</ComboBox>

for child(Subcategory) combo i am using:

<ComboBox Grid.Column="1" Grid.Row="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="0,2,10,2" TabIndex="1"
ItemsSource="{Binding SelectedItem, ElementName=categoryComboBox, Mode=OneWay}"
DisplayMemberPath="SubCategoryName" SelectedValuePath="SubCategoryId"
SelectedItem="{Binding INVSubCategories, Mode=TwoWay}">
</ComboBox>

But my child combo items is not populated during form loading as well as parent combo's selection changed though my parent combo items are populated. i can't figure out why my child combo is not functioning based on parent combo's selected item ,please help me.

[Venkatesh Mookkan]

Check whether you implemented INotifyPropertyChanged interface for Category class object.

Castle Rider

What if I freeze??? Don't forget to breath...

My: Website | Yahoo Group | Blog Spot

/xml>

[bindum31]

Thanks Castle Rider for your reply. I have made a Generic "BasePresenter" class where i have implemented INotifyPropertyChanged interface in the following way:

public event PropertyChangedEventHandler PropertyChanged;

protected void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = this.PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}

And in my Presenter class I have used:

    public ObservableCollection<INVCategory> CategoryList
    {
        get
        {
            return this.categoryList;
        }

        set
        {
            this.categoryList = value;
            **OnPropertyChanged**("CategoryList");
            
        }
    }

[Venkatesh Mookkan]

Try adding UpdateSourceTrigger=PropertyChanged along with the ItemsSource Binding xaml.

Castle Rider

What if I freeze??? Don't forget to breath...

My: Website | Yahoo Group | Blog Spot

/xml>

[bindum31]

I am not clear. Would you please send me a sample code.

[Venkatesh Mookkan]

Try this binding in categoryCombo SelectedValue="{Binding Path=CurrentEntity.CategoryId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

Castle Rider

What if I freeze??? Don't forget to breath...

My: Website | Yahoo Group | Blog Spot

/xml>