Send collection to Command parameter

Question

I am doing command binding with button. It's working fine but when I try to add a new object through bound command. One of my property comming from GUI becomes null when it fires. If I try to add CommandParameter then it always return null. The property which I want to send through CommandParameter contain all hierarchies of objects and collections. Guide me please how should I bind this type of property? It ll be really appreciated.

Answer 1

Hi maifs,

Could you share me with the command codes and the xaml?

As you mentioned , you want to send a collection, could you show me the detail of the collection?

If the collection is in the viewmodel , instead of sending it , you can read it directly in your viewmodel.

If the collection isn't in the viewmodel , you can set it as param as the code below:

       
 <ListBox Name="listBox">
        </ListBox>
        <Button Content="Load" Width="120"     
                Command="{Binding DemoCommand}"     
                CommandParameter="{Binding ElementName=listBox, Path=ItemsSource}" />

        
public MainPage()
        {
            InitializeComponent();
            IList<string> strList = new List<string> { "0", "1", "2" };
            listBox.ItemsSource = strList;
        }

 

public class MainViewModel : ViewModelBase
    {
        public ICommand DemoCommand { get; set; }
        public MainViewModel()
        {
            DemoCommand = new DelegateCommand(CanLoadDemos, LoadDemos);
        }
        private void LoadDemos(object param)
        {
            return;
        }
        private bool CanLoadDemos(object param)
        {
            return true;
        }
    }

    public class DelegateCommand : ICommand
    {
        public event EventHandler CanExecuteChanged;

        Func<object, bool> _canExecute = null;
        Action<object> _executeAction = null;

        public DelegateCommand(Func<object, bool> canExecute, Action<object> executeAction)
        {
            _canExecute = canExecute;
            _executeAction = executeAction;
        }
        public bool CanExecute(object parameter)
        {
            if (_canExecute != null)
                return _canExecute(parameter);
            return true;
        }

        public void UpdateCanExecuteState()
        {
            if (CanExecuteChanged != null)
                CanExecuteChanged(this, new EventArgs());
        }

        public void Execute(object parameter)
        {
            if (_executeAction != null)
                _executeAction(parameter);
            UpdateCanExecuteState();
        }
    }

Please put breakpoint to the LoadDemos method, and you can see the list is there.

Answer 2

Otomi thanks for guiding. I 'll share my xaml tomorrow ASAP and sorry for late reply because I couldn't see the reply of my post. Yes it is not a part of view model that's why I want to send it through command parameter. It contains more than 7 to 9 hundred collections( in some case collection of collections.) I ll try according to your provided solution tomorrow But Otomi I could't get you that how could I bind CommandParameter with this type of collection if I don't use any control as you mentioned .

Answer 3

Hi maifs,

Could you share the collection datatype of your data?

Maybe you should change the datatype in order to send it to the command parameter.

Answer 4

Hi Otomii.

Sorry if i am doing in some wrong way:

 

 

DataType is ProposalManager and its contain too many collection itself.

=====================ucInsurance.cs================================

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using NetSol.Silverlight.Core;
using NFS.UI.Silverlight.ServiceClient;
using System.Collections.ObjectModel;
using NFS.UI.Silverlight.ServiceClient.ProposalProxy;
using Lookup = NFS.UI.Silverlight.ServiceClient.LookupProxy;
using NFS.UI.Silverlight.ViewModels;
using NetSol.Web.Controls.Silverlight;

namespace NFS.UI.Silverlight.UserControls
{
    public partial class ucInsurance : Popup
    {
        #region Constructor

        public ucInsurance()
        {
            InitializeComponent();
            PostInitialize();
            viewModel = new InsuranceViewModel();
            
        }

        #endregion

        #region Properties

        private ProposalManager _proposalManager;
        private ProposalManager Controller
        {
            get
            {
                if (_proposalManager == null)
                    _proposalManager = GetController<ProposalManager>(this);
                return _proposalManager;
            }
        }

        private InsuranceViewModel viewModel;

        #endregion

        #region Get/Set Data

        protected override bool SetData()
        {            
            SetData(Controller.Helper.AssetIndex);
            return true;
        }

        protected override bool SetData(int index)
        {
            viewModel = new InsuranceViewModel() { Controller = Controller};

            if (viewModel.Controller == null)
                viewModel.Controller = Controller;

	    SyncBinding();

            return true;
        }

        #endregion


	private void SyncBinding()
        {
            if (viewModel.AssetExist())
            {
                gvInsuranceDetails.ItemsSource = viewModel.Controller.DataContext.ASSET
                    .Current<AssetEntity>()[Controller.Helper.AssetIndex].PROPOSALASSETINSURANCE.Current<PRPLASETINSRInfo>();
            }
        }     
          
      
    }
}


=======================ucInsurance.xaml=========================== 

	<nfs:Popup x:Class="NFS.UI.Silverlight.UserControls.ucInsurance"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:nfs="clr-namespace:NetSol.Silverlight.Core;assembly=NetSol.Silverlight.Core"
    xmlns:ns="clr-namespace:NetSol.Web.Controls.Silverlight;assembly=NetSol.Web.Controls.Silverlight"
    xmlns:ctrl="clr-namespace:NFS.UI.Silverlight.Controls"
    xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
    xmlns:uc="clr-namespace:NFS.UI.Silverlight.UserControls"
    xmlns:viewModel="clr-namespace:NFS.UI.Silverlight.ViewModels"
    xmlns:toolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Toolkit"                   
    mc:Ignorable="d" Header="Insurance Details"
    d:DesignHeight="200" d:DesignWidth="1250" Height="400" Width="1250" >
    <toolkit:BusyIndicator>
        <Grid x:Name="LayoutRoot" Style="{StaticResource GridStyle}">
            <Grid.Resources>
                <viewModel:InsuranceViewModel x:Key="AssetInsurance" />
            </Grid.Resources>
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
                <RowDefinition Height="*" />
                <RowDefinition Height="Auto" />
                <RowDefinition Height="25" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition />
            </Grid.ColumnDefinitions>
            <ctrl:ValidationMessages x:Name="validator" Grid.Row="0"/>

            <ns:GridView x:Name="gvInsuranceDetails"  Style="{StaticResource GridViewCommonStyle}" Grid.Row="1">
                <ns:GridView.Columns>                   
                    <ns:GridViewDataColumn IsFilterable="False" Width="100"  MinWidth="100">
                        <ns:GridViewDataColumn.Header>
                            <ns:Label  HorizontalAlignment="Center" HorizontalContentAlignment="Right" Content ="Financed" />
                        </ns:GridViewDataColumn.Header>
                        <ns:GridViewDataColumn.CellTemplate>
                            <DataTemplate>
                                <ns:CheckBox IsChecked="{Binding FINANCEDIND,Mode=TwoWay}" HorizontalAlignment="Center" />
                            </DataTemplate>
                        </ns:GridViewDataColumn.CellTemplate>                                        
                </ns:GridView.Columns>
            </ns:GridView>
            <StackPanel Grid.Row="3" Style="{StaticResource StackPanelHorizontalLeftToRightStyle}">                
                <ns:Button x:Name="btnAdd" Content="Add"  Style="{StaticResource ButtonLeftMarginStyle}"  
                Command="{Binding InsuranceAddCommand,Source={StaticResource AssetInsurance}}" CommandParameter="{Binding ProposalManager}"  />               
            </StackPanel>
        </Grid>
    </toolkit:BusyIndicator>
</nfs:Popup>

===========================================InsuranceViewModel =======================


 public class InsuranceViewModel : ViewModelBase
    {
        #region Constructors

        public InsuranceViewModel()
        {            

        }

        public InsuranceViewModel(ProposalManager controller)
            : this()
        {
            m_controller = controller;
        }

        #endregion

        #region Properties
        private ProposalManager m_controller;
        public ProposalManager Controller
        {
            set
            {
                m_controller = value;
            }
            get
            {
                if (m_controller != null)
                    return m_controller;
                return null;
            }

        }
       

        #endregion       


        public void AddProposalAssetInsurance()
        {
            int seqID = 0;
            if (AssetExist())
            {
                ObservableCollection<PRPLASETINSRInfo> proposalInsurance = Controller.DataContext.ASSET.Current<AssetEntity>()[Controller.Helper.AssetIndex].
                        PROPOSALASSETINSURANCE.Current<PRPLASETINSRInfo>();

                if (proposalInsurance.Count > 0)
                {
                    seqID = proposalInsurance.Select(s => s.INSRSEQID).Max() + 1;
                }
                else
                {
                    seqID = 1;
                }

                PRPLASETINSRInfo proposalAssetInsurance = new PRPLASETINSRInfo()
                {
                    RowState = DataRowState.Added,
                    INSRSEQID = seqID,
                    SESSIONID = SessionBean.UserSessionObject.User.SessionId,
                    SESSIONCDE = SessionBean.UserSessionObject.User.SessionCode
                };

                Controller.DataContext.ASSET[Controller.Helper.AssetIndex].PROPOSALASSETINSURANCE.Add(proposalAssetInsurance);
            }
        }

       

        #endregion

        private ICommand _insuranceAddCommand;
        public ICommand InsuranceAddCommand
        {
            get
            {
                if (_insuranceAddCommand == null)
                    _insuranceAddCommand = new DelegateCommand(OnInsuranceAddCommandExecuted);
                return _insuranceAddCommand;
            }
        }
        private void OnInsuranceAddCommandExecuted(object parameter)
        {           
		Controller = (ProposalManager)parameter;	
	 	AddProposalAssetInsurance()
        }

    }

Answer 5

Hi otomi. See Above mentioned source please and let me know in case of any confusion.

Answer 6

Hi,

I've had a marry leave these days.

I will try your code as soon as possible.

Answer 7

Hi otomi congratulations :) No problem , you can take time as much as you can.

Answer 8

Hi,

what is the type ProposalManager?

Could you show me the object definition?

and more ,Could you set a BreakPoint to the xaml,to see whether it bind fine.

(Or just change the binding to a IList Collect to see whether it bind fine)

Answer 9

 <ns:Button x:Name="btnAdd" Content="Add" Style="{StaticResource 

ButtonLeftMarginStyle}" Command="{Binding InsuranceAddCommand,Source={StaticResource 

AssetInsurance}}" CommandParameter="{Binding ProposalManager}" /> 


And the CommandParameter="{Binding ProposalManager} is binding to a Class name ,not a created 

object. Maybe you should bind to Controller.

        private ProposalManager _proposalManager;
        private ProposalManager Controller
        {
            get
            {
                if (_proposalManager == null)
                    _proposalManager = GetController<ProposalManager>(this);
                return _proposalManager;
            }
        }

And in the code , there are two private key words.

Answer 10

Hi Otomi. I tried with both Controller as well as ProposalManager but I received controller null each time. Yes it's private but Otomi should it have some impacts if we set a controller property of viewModel in our GUI and pass it. Then why is it getting null value? It works fine when I directly call the required method of ViewModel and in case of using Command controller becomes Null.