populate wpf textbox from listbox selected item - MVVM

Question

Hello,
I am working on WPF MVVM...
The window has a listbox which is populated with FullNames of students
The bit I need help on is when you click on a name in the listbox then the textboxes to be populated with FirstName in textbox1 and textbox2 with Address1 fields

This is what I am doing so far but DetailData does not seem to be populating...

//frmDetailsTest

<Window x:Class="Rustam.frmDetailsTest"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="frmDetailsTest" Height="501.6" Width="455.686"
        xmlns:scr="clr-namespace:Rustam"
        Loaded="Window_Loaded">

    <Window.Resources>
        <scr:clsStudentViewModel x:Key="StudentViewModel"/>
    </Window.Resources>
    <Grid Margin="0,0,5.2,-0.2"
          DataContext="{Binding Source={StaticResource StudentViewModel}}">
        <StackPanel Orientation="Vertical">
            <ListBox Name="lstNames" 
                 ItemsSource="{Binding Path=DataCollection}"
                 SelectedValuePath="StudentID"
                 DisplayMemberPath="FullName"
                 HorizontalAlignment="Left" Height="253" Margin="10,10,0,0" VerticalAlignment="Top" Width="236" SelectionChanged="lstNames_SelectionChanged" Grid.ColumnSpan="7"
                 >
            </ListBox>
            <Grid Grid.Row="2"
                  Margin="5,5,4.6,5"
                  x:Name="grdDetail"
                   Height="166"
                  DataContext="{Binding Path=DetailData}"
                  >
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="120"></ColumnDefinition>
                    <ColumnDefinition Width="*"></ColumnDefinition>
                </Grid.ColumnDefinitions>
                <TextBox 
                    Text="{Binding Path=Address1, Mode=TwoWay}"
                    Grid.Column="1" HorizontalAlignment="Left" Height="23" Margin="10,9.2,0,-30.6" Grid.Row="1" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
                <TextBox 
                    Text="{Binding Path=FirstName, Mode=TwoWay}"
                    Grid.Column="1" HorizontalAlignment="Left" Height="23" Margin="10,37.2,0,-57" Grid.Row="1" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
            </Grid>
        </StackPanel>

    </Grid>
</Window>

using System.Data;
using System.Data.SqlClient;
using System.ComponentModel;
using System.Collections.ObjectModel;
using DataAccess;

namespace Rustam
{
    public class clsStudentViewModel : INotifyPropertyChanged
    {
        clsStudentAccess _DataManager = new clsStudentAccess();

        #region Constructor - Initialize Product Data Collection
        public clsStudentViewModel()
        {
            DataCollection = _DataManager.GetStudentNamesCol();
        }
        #endregion
        
        #region INotifyPropertyChanged
        public event PropertyChangedEventHandler PropertyChanged;
        protected void RaisePropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = this.PropertyChanged;
            if (handler != null)
            {
                PropertyChangedEventArgs args = new PropertyChangedEventArgs(propertyName);

                // Raise the PropertyChanged event.
                handler(this, args);
            }
        }
        #endregion

        #region DataCollection Property
        private ObservableCollection<clsStudentDetails> _DataCollection;

        public ObservableCollection<clsStudentDetails> DataCollection
        {
            get { return _DataCollection; }
            set
            {
                _DataCollection = value;
                RaisePropertyChanged("DataCollection");
            }
        }
        #endregion

        #region DetailData Property
        private clsStudentDetails mDetailData;

        public clsStudentDetails DetailData
        {
            get { return mDetailData; }
            set
            {
                mDetailData = value;
                RaisePropertyChanged("DetailData");
            }
        }
        #endregion
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.Common;
using System.ComponentModel;
using System.Collections.ObjectModel;

namespace DataAccess
{
    public class clsStudentAccess 
    {   
        public ObservableCollection<clsStudentDetails> GetStudentNamesCol()
        {
            ObservableCollection<clsStudentDetails> ret = new ObservableCollection<clsStudentDetails>();

            // get a configured DbCommand object
            DbCommand comm = clsGenericDataAccess.CreateCommand();
            // set the stored procedure name
            comm.CommandText = "uspGetAllStudentNames";
            // execute the stored procedure and return the results
            DataTable table = new DataTable();
            table = clsGenericDataAccess.ExecuteSelectCommand(comm);

            if (table.Rows.Count > 0)
            {
                foreach (DataRow dr in table.Rows)
                {
                    clsStudentDetails student = new clsStudentDetails();

                    student.StudentID = int.Parse(dr["StudentID"].ToString());
                    student.FullName = dr["FullName"].ToString();

                    ret.Add(student);
                }
            }                      

            return ret;
        }


public clsStudentDetails GetStudentDetailsUniqueMVVM(int intStudentID)
        {
            DbCommand comm = clsGenericDataAccess.CreateCommand();
            comm.CommandText = "uspGetStudentDetailsUnique";

            DbParameter param = comm.CreateParameter();
            if (intStudentID > 0)
            {
                param.ParameterName = "@StudentID";
                param.Value = intStudentID;
                param.DbType = DbType.Int32;
                comm.Parameters.Add(param);
            }

            DataTable table = new DataTable();
            table = clsGenericDataAccess.ExecuteSelectCommand(comm);
            clsStudentDetails details = new clsStudentDetails();
            if (table.Rows.Count > 0)
            {
                details.FirstName = table.Rows[0]["FirstName"].ToString();
                details.Address1 = table.Rows[0]["Address1"].ToString();
            }

            return details;
        }
--------------------------------------------------------------------
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;

namespace DataAccess
{
    public class clsStudentDetails : INotifyPropertyChanged
    {

        #region INotifyPropertyChanged
        public event PropertyChangedEventHandler PropertyChanged;

        protected void RaisePropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        #endregion

        private int _StudentID;
        public int StudentID
        {
            get { return _StudentID; }
            set
            {
                if (_StudentID != value)
                {
                    _StudentID = value;
                    RaisePropertyChanged("StudentID");
                }
            }
        }

        private string _FullName;
        public string FullName
        {
            get { return _FullName; }
            set
            {
                if (_FullName != value)
                {
                    _FullName = value;
                    RaisePropertyChanged("FullName");
                }
            }
        }

        private string _FirstName;
        public string FirstName
        {
            get { return _FirstName; }
            set
            {
                if (_FirstName != value)
                {
                    _FullName = value;
                    RaisePropertyChanged("FirstName");
                }
            }
        }

        private string _Address1;
        public string Address1
        {
            get { return _Address1; }
            set
            {
                if (_Address1 != value)
                {
                    _Address1 = value;
                    RaisePropertyChanged("Address1");
                }
            }
        }
    }
}

Answer 1

Hi arkiboys,

you need to set the DetailData-property of your ViewModel when an item in the ListBox is selected. To do this, bind the SelectedItem-Property of the ListBox to the DetailData-property of your ViewModel:

 <ListBox Name="lstNames" 
                 ItemsSource="{Binding Path=DataCollection}"
                 SelectedItem="{Binding Path=DetailData,Mode=TwoWay}"

Now you see the Address shows up correctly, but not so the FirstName. The FirstName does not show up because you've a typo in the property. When you look at your code, you see that you set the _FullName-field inside of the setter instead of the _FirstName-field. So change this like here:

  public string FirstName
    {
      get { return _FirstName; }
      set
      {
        if (_FirstName != value)
        {
          _FirstName = value;
          // _FullName = value;
          RaisePropertyChanged("FirstName");
        }
      }
    }

Now it works like a charm. ;-)

---

Thomas Claudius Huber

"If you can't make your app run faster, make it at least look & feel extremly fast"

My latest Pluralsight-courses:
XAML Layout in Depth
Windows Store Apps - Data Binding in Depth

twitter: @thomasclaudiush
homepage: www.thomasclaudiushuber.com

Answer 2

Hi arkiboys,

you need to set the DetailData-property of your ViewModel when an item in the ListBox is selected. To do this, bind the SelectedItem-Property of the ListBox to the DetailData-property of your ViewModel:

 <ListBox Name="lstNames" 
                 ItemsSource="{Binding Path=DataCollection}"
                 SelectedItem="{Binding Path=DetailData,Mode=TwoWay}"

Now you see the Address shows up correctly, but not so the FirstName. The FirstName does not show up because you've a typo in the property. When you look at your code, you see that you set the _FullName-field inside of the setter instead of the _FirstName-field. So change this like here:

  public string FirstName
    {
      get { return _FirstName; }
      set
      {
        if (_FirstName != value)
        {
          _FirstName = value;
          // _FullName = value;
          RaisePropertyChanged("FirstName");
        }
      }
    }

Now it works like a charm. ;-)

---

Thomas Claudius Huber

"If you can't make your app run faster, make it at least look & feel extremly fast"

My latest Pluralsight-courses:
XAML Layout in Depth
Windows Store Apps - Data Binding in Depth

twitter: @thomasclaudiush
homepage: www.thomasclaudiushuber.com

Still I do not get my textboxes populated after I select a name from the listbox.
I think somewhere I need to call the database by passing the selected StudentID and get the FirstName and Address1 of that StudentID

?

Thanks

Answer 3

Think about it.

How was Thomas ( or anyone ) supposed to know you hadn't got the address from the database?

Anyone trying to answer your questions only knows what you tell us.

---

Hope that helps.

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