Issue with binding GridViewSelectColumn from ViewModel

[Jebouy]

 

Hi,

   I am having an MVVM application  I am not able to view GridViewSelectColumn as selected  even after setting the "selected" property from viewmodel. Below is the code

From UI it is working fine. If you can give your email id then i can send the sample code.  

 

 

 

<telerikGridView:RadGridView
            x:Name="grdEntity"
            ItemsSource="{Binding Entities}"
            RowIndicatorVisibility="Collapsed"
            AutoGenerateColumns="False"
            IsReadOnly="True"
            HorizontalAlignment="Left"
            ShowGroupPanel="False"
            GridLinesVisibility="Horizontal"
            Margin="0"
            Grid.Row="0"
            Width="200"
            SelectionMode="Multiple"
            cmd:RadGridExtensions.SelectAll="{Binding SelectAll, Mode=TwoWay}"
            >
            <telerikGridView:RadGridView.Columns>

                <telerikGridView:GridViewSelectColumn Width="25"/>

                <telerikGridView:GridViewDataColumn
                            Header="Name"
                            UniqueName="Name"
                            IsGroupable="False"
                            TextWrapping="Wrap"/>
            </telerikGridView:RadGridView.Columns>
        </telerikGridView:RadGridView>



/***********************
Business Entity
*********************/
public class Entity : INotifyPropertyChanged, IRadGridMultiSelect
    {
        private bool m_selected;
        private string m_name;

        public string Name
        {
            get
            {
                return m_name;
            }
            set
            {
                m_name = value;
                OnPropertyChanged("Name");
            }
        }

        public bool Selected
        {
            get { return m_selected; }
            set { m_selected = value;
            OnPropertyChanged("Selected");
            }
        }
        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        #endregion

        #region IRadGridMultiSelect Members

        public void Select(bool val)
        {
            this.Selected = val;
        }

        #endregion

        void OnPropertyChanged(string propName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propName));
        }
    }

/****************************
View Model
**********************************/
 public class MainPageViewModel : INotifyPropertyChanged
    {

        #region Private Members

        private ICommand _buttonClickedCommand;

        private ObservableCollection<Entity> m_entities = new ObservableCollection<Entity>();
        private bool m_SelectAll;
        private string m_Count;

        #endregion

        #region Constructor

        public MainPageViewModel()
        {
            CreateEntities();
        }

        #endregion

        #region Public Members

        private void CreateEntities()
        {
            Entities.Add(new Entity() { Selected = true, Name = "Joe" });
            Entities.Add(new Entity() { Selected = true, Name = "Rick" });
            Entities.Add(new Entity() { Selected = false, Name = "Nate" });
            Entities.Add(new Entity() { Selected = false, Name = "Jim" });
        }
        public ICommand ButtonClickedCommand
        {
            get
            {
                if (_buttonClickedCommand == null)
                    _buttonClickedCommand = new RelayCommand((p) => OnCountClicked(p), null);
                return _buttonClickedCommand;
            }
        }


        public string Count
        {
            get { return m_Count; }
            set
            {
                m_Count = value;
                this.OnPropertyChanged("Count");
            }
        }


        public bool SelectAll
        {
            get { return m_SelectAll; }
            set
            {
                m_SelectAll = value;
                this.OnPropertyChanged("SelectAll");
            }
        }
        public ObservableCollection<Entity> Entities
        {
            get
            {
                return m_entities;
            }
            set
            {
                m_entities = value;
                OnPropertyChanged("Entities");
            }
        }

        #endregion

        #region Event Handlers

        public void OnCountClicked(object args)
        {
            Count = Entities.Where(x => x.Selected == true).Count().ToString();
        }



        #endregion

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        void OnPropertyChanged(string propName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propName));
        }

        #endregion
    }

/*******************************
RadGrid Extension
********************************/
  public interface IRadGridMultiSelect
    {
        void Select(bool val);
    }
   public static class RadGridExtensions
    {

        #region SelectAll

        public static bool GetSelectAll(DependencyObject obj)
        {
            return (bool)obj.GetValue(SelectAllProperty);
        }

        public static void SetSelectAll(DependencyObject obj, bool value)
        {
            obj.SetValue(SelectAllProperty, value);
        }

        // Using a DependencyProperty as the backing store for SelectAll.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty SelectAllProperty =
            DependencyProperty.RegisterAttached("SelectAll", typeof(bool), typeof(RadGridExtensions), new PropertyMetadata(true, OnSelectAllChanged));

        //public static int count = 0;
        private static void OnSelectAllChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var radGrid = (RadGridView)d;

            if (radGrid.Tag == null )
            {
                radGrid.SelectionChanged += (s, ev) =>
                {
                    ReSetSelectAll(radGrid, ev);
                };
                radGrid.Tag = "1";
            }

        }

        private static void ReSetSelectAll(RadGridView radGrid, Telerik.Windows.Controls.SelectionChangeEventArgs e)
        {
            if (radGrid.ItemsSource != null)
            {
                foreach (var item in e.AddedItems)
                {
                    var i = item as IRadGridMultiSelect;
                    if (i != null)
                        i.Select(true);
                }
                foreach (var item in e.RemovedItems)
                {
                    var i = item as IRadGridMultiSelect;
                    if (i != null)
                        i.Select(false);
                }

                //if (((IList)radGrid.ItemsSource).Count == radGrid.SelectedItems.Count)
                //{
                //    SetSelectAll(radGrid, false);
                //    SetSelectAll(radGrid, true);
                //}
                //else if (radGrid.SelectedItems.Count == 0)
                //{
                //    SetSelectAll(radGrid, false);
                //}
            }

        }

        #endregion

    }

[Maya]

Hi Jebouy,

May you provide a bit more details about the exact scenario you want to accomplish ? Generally, the IsChecked property of each of the CheckBox-es in the column is bound to the IsSelected property of the corresponding row. So, you may use the SelectedItem or SelectedItems collection of the grid.
 

All the best,
Maya
the Telerik team

[Jebouy]

Hi,
    
 Here my scenario is:  there are certain records already got saved. In the update screen i have to show the previous saved records as selected while initial load.

  in the  CreateEntities() method i have two items have selected properties as true. which is not reflecting in the grid UI.

private void CreateEntities()
        {
            Entities.Add(new Entity() { Selected = true, Name = "Joe" });
            Entities.Add(new Entity() { Selected = true, Name = "Rick" });
            Entities.Add(new Entity() { Selected = false, Name = "Nate" });
            Entities.Add(new Entity() { Selected = false, Name = "Jim" });
        }

I am not able to attach any zip file here. other wise i could have to send the sample code.

[Vlad]

Hi,

 You can attach zips only in support tickets. 

Greetings,
Vlad
the Telerik team