Binding SetectedItem in ComboBox WPF - wpf

Question

I have a UserControl with ComboBox.
<ComboBox Grid.Row="8" Grid.Column="1"
VerticalAlignment="Center"
x:Name="cmbCategory"
ItemsSource="{Binding ElementName=ucAppiGeneralInfo, Path=Categories, Mode=TwoWay}"
SelectedItem="{Binding ElementName=ucAppiGeneralInfo, Path=SelectedCategory, Mode=TwoWay}"
IsEditable="True"
IsSynchronizedWithCurrentItem="True"
SelectedValuePath="CAT_ID"
TextSearch.TextPath="CAT_NAME">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Path=CAT_NAME}"/>
<TextBlock Text=" - "/>
<TextBlock Text="{Binding Path=PUBLIC_DESCRIPTION}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
The code behind is:
public partial class AppiGeneralInfoUC : UserControl
{
public DataTable Categories
{
get { return (DataTable)GetValue(CategoriesProperty); }
set { SetValue(CategoriesProperty, value);}
}
public static readonly DependencyProperty CategoriesProperty =
DependencyProperty.Register(
"Categories",
typeof(DataTable),
typeof(AppiGeneralInfoUC),
new UIPropertyMetadata(null));
public String SelectedCategory
{
get { return (String)GetValue(SelectedCategoryProperty); }
set
{
SetValue(SelectedCategoryProperty, value);
}
}
public static readonly DependencyProperty SelectedCategoryProperty =
DependencyProperty.Register(
"SelectedCategory",
typeof(String),
typeof(AppiGeneralInfoUC),
new UIPropertyMetadata(null));
public AppiGeneralInfoUC()
{
InitializeComponent();
}
}
I have a window which use the UserControl:
<TabControl>
<TabItem Header="Information">
<my:AppiGeneralInfoUC x:Name="ucAppiGeneralInfo"
Categories="{Binding Path=Categories, Mode=TwoWay}"
SelectedCategory="{Binding Path=SelectedCategory, Mode=TwoWay}" />
</TabItem>
the code behind is:
public partial class ApplicationWindow : Window
{
VMBase appiGeneralInfoWin = new AppiGeneralInfoVM();
public ApplicationWindow()
{
InitializeComponent();
ucAppiGeneralInfo.DataContext = appiGeneralInfoWin;
}
public void updateAction(string cat_id)
{
this.Title = "Update application";
(appiGeneralInfoWin as AppiGeneralInfoVM).setSelectedCategory(cat_id);
} ...
And finally I have ViewModel class:
class AppiGeneralInfoVM : VMBase
{
private DataTable categories = null;
private String selectedCategory = null;
public DataTable Categories
{
get { return this.categories; }
set
{
this.categories = value;
this.OnPropertyChanged("Categories");
}
}
public String SelectedCategory
{
get { return this.selectedCategory; }
set
{
this.selectedCategory = value;
this.OnPropertyChanged("SelectedCategory");
}
}
public AppiGeneralInfoVM()
{
ServicesLoader.LoadRunTimeServices();
Categories = GetService<CategoryBLL>().getCategories();
}
public void setSelectedCategory(string cat_id)
{
SelectedCategory = Categories.Select("cat_id =" + "'"+cat_id+"'")[0]["CAT_NAME"].ToString();
}
Everything works well but i have problem with the selectedItem (SelectedCategory),
it's not update at all....

Answer 1

I think it happens because your SelectedItem has string type while your collection is DataTable (which enumerates DataRow). Try changing your collection to be IEnumerable<string>