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

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");
            
        }
    }

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.

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

  var categories = from category in this.Context.INVCategories
                   orderby category.CatgeoryId descending
                   select category;
  return new   ObservableCollection<INVCategory>(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.

Dear all, When i use Dataset to retrieve data from WCF service to client according to the following process it works perfectly:

public DataSet GetJobs()
{
SqlConnection cn = new SqlConnection(@"Data Source=dotnet02\SQLEXPRESS;Initial Catalog=pubs;Integrated Security=True");
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter("Select * from jobs", cn);
da.Fill(ds, "jobs");
return ds;
}

But when i want to return LIST<Job>instead of Dataset in the follwing way i can't access the method from Client side though after modification of my service code i take the reference of my service from the client as before.

public List<Job> GetJobs()
{
SqlConnection cn = new SqlConnection(@"Data Source=dotnet02\SQLEXPRESS;Initial Catalog=pubs;Integrated Security=True");
string sqlstat = "select * from jobs";
SqlCommand cmd = new SqlCommand(sqlstat, cn);
SqlDataReader dr = cmd.ExecuteReader();
List<Job> allJobs = new List<Job>();
Job jobObj;
while (dr.Read())
{
jobObj = new Job();
jobObj.Description = dr["job_desc"].ToString();
jobObj.MinLevel = Convert.ToInt32(dr["min_lvl"]);
jobObj.MaxLevel = Convert.ToInt32(dr["max_lvl"]);
allJobs.Add(jobObj);
}
return allJobs;
}

I can't figure out the problem! How can i do this? Any help will be highly appreciated.