Wpf DataGridTemplateColumn ComboBox displayed text after selected an item

Question

I have a datagrid that uses a DataGridTemplateColumn and in the CellEditingTemplate a combobox. Everything works okay until a value is selected. I've spent a ton of time trying to figure out how to make this work. Basically a user selects a text item (Display Text) from the combobox, the value needed for the database is stored as the selected value, and the user only ever sees the display text. The way it behaves now is the user only sees the display text when opening the combobox to select an item. But after the item is selected the selected value is shown. Below is my xaml and vb code and screen shots.

Selecting an item from the combobox shows the display text, which is good.

After the user selects an item, instead of the display text being shown, the selected value is; which is what i don't want.

<Window.Resources>
    <ObjectDataProvider x:Key="dispProvider" ObjectType="{x:Type local:QCDisposition}"
                        MethodName="GetDispositions"></ObjectDataProvider>
    <ObjectDataProvider x:Key="defectDeptProvider" ObjectType="{x:Type local:QCDefectDept}"
                        MethodName="GetDepts"></ObjectDataProvider>

</Window.Resources>

<DataGridTemplateColumn x:Name="DispositionCol" Header="Disposition">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <TextBlock x:Name="txtDisposition" Text="{Binding DispositionID, UpdateSourceTrigger=PropertyChanged}" />
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
                <DataGridTemplateColumn.CellEditingTemplate>
                    <DataTemplate>
                        <ComboBox x:Name="cboDisposition" DisplayMemberPath="DefectDesc" SelectionChanged="DispositionChanged" ItemsSource="{Binding Source={StaticResource dispProvider}}" SelectedItem="DispositionID" SelectedValuePath="DispositionID" SelectedValue="DispositionID" />
                    </DataTemplate>
                </DataGridTemplateColumn.CellEditingTemplate>
                <DataGridTemplateColumn.CellStyle>
                    <Style>
                        <Setter Property="TextBlock.MinWidth"  Value="100" />
                        <Setter Property="TextBlock.TextAlignment" Value="Left" />
                    </Style>
                </DataGridTemplateColumn.CellStyle>
            </DataGridTemplateColumn>

Class to get disposition codes:

Public Class QCDisposition
Implements INotifyPropertyChanged

Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

'Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
    If Not PropertyChangedEvent Is Nothing Then
        RaiseEvent PropertyChanged(Me, e)
    End If
End Sub

Private _dispositionID As Integer
Public Property QCDispID() As Integer
    Get
        Return _dispositionID
    End Get
    Set(ByVal value As Integer)
        _dispositionID = value
        OnPropertyChanged(New PropertyChangedEventArgs("QCDispositionID"))
    End Set
End Property

Private _defectCode As String
Public Property DefectDesc() As String
    Get
        Return _defectCode
    End Get
    Set(ByVal value As String)
        _defectCode = value
        OnPropertyChanged(New PropertyChangedEventArgs("DefectCode"))
    End Set
End Property

Public Sub New(dispositionID As Integer, defectCode As String)
    Me.QCDispID = dispositionID
    Me.DefectDesc = defectCode
End Sub

Public Shared Function GetDispositions() As ICollection(Of QCDisposition)
    Try
        Dim m_Dispositions As ObservableCollection(Of QCDisposition) = New ObservableCollection(Of QCDisposition)()

        Dim db1 As New QCDispositionDataContext

        Dim disp = From go In db1.QCDispositionCodes
                       Select go

        For Each g In disp
            m_Dispositions.Add(New QCDisposition(g.QCDispositionID, g.DefectCode))
        Next

        Return m_Dispositions
    Catch ex As Exception
        MessageBox.Show(ex.Message, "Unhandled Error", MessageBoxButton.OK, MessageBoxImage.Error)
        Return Nothing
    End Try
End Function
End Class

QC class:

Imports System.ComponentModel
Imports System.Collections.ObjectModel

Public Class QCItem
Inherits ObjectBase
Implements INotifyPropertyChanged

Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
    If Not PropertyChangedEvent Is Nothing Then
        RaiseEvent PropertyChanged(Me, e)
    End If
End Sub

Private _salesOrder As Integer
Public Property SalesOrder() As Integer
    Get
        Return _salesOrder
    End Get
    Set(value As Integer)
        _salesOrder = value

        OnPropertyChanged(New PropertyChangedEventArgs("fldSalesOrder"))
    End Set
End Property

Private _productRecordNo As Integer
Public Property ProductRecordNumber() As Integer
    Get
        Return _productRecordNo
    End Get
    Set(value As Integer)
        _productRecordNo = value

        OnPropertyChanged(New PropertyChangedEventArgs("fldProductRecordNumber"))
    End Set
End Property

Private _taskNumber As Integer
Public Property TaskNumber() As Integer
    Get
        Return _taskNumber
    End Get
    Set(value As Integer)
        _taskNumber = value

        OnPropertyChanged(New PropertyChangedEventArgs("fldTaskNumber"))
    End Set
End Property

Private _qcDesc As String
Public Property Description() As String
    Get
        Return _qcDesc
    End Get
    Set(value As String)
        _qcDesc = value

        OnPropertyChanged(New PropertyChangedEventArgs("fldDescription"))
    End Set
End Property

Private _enteredBy As String
Public Property EnteredBy() As String
    Get
        Return _enteredBy
    End Get
    Set(value As String)
        _enteredBy = value

        OnPropertyChanged(New PropertyChangedEventArgs("fldEnteredBy"))
    End Set
End Property

Private _enteredDate As String
Public Property EnteredDate() As String
    Get
        Return Convert.ToString(Convert.ToDateTime(_enteredDate).ToShortDateString)
    End Get
    Set(value As String)
        _enteredDate = value

        OnPropertyChanged(New PropertyChangedEventArgs("fldEnteredDate"))
    End Set
End Property

Private _completedDate As Nullable(Of Date)
Public Property CompletedDate() As Nullable(Of Date)
    Get
        Return _completedDate
    End Get
    Set(value As Nullable(Of Date))
        _completedDate = value
        OnPropertyChanged(New PropertyChangedEventArgs("fldCompleteDate"))
    End Set
End Property

Private _dispositionID As Integer
Public Property DispositionID() As Integer
    Get
        Return _dispositionID
    End Get
    Set(value As Integer)
        _dispositionID = value

        OnPropertyChanged(New PropertyChangedEventArgs("QCDispositionID"))
    End Set
End Property

Private _deptCodeID As Decimal
Public Property DeptCodeID() As Decimal
    Get
        Return _deptCodeID
    End Get
    Set(value As Decimal)
        _deptCodeID = value

        OnPropertyChanged(New PropertyChangedEventArgs("QCDeptCodeID"))
    End Set
End Property

Public Sub New(ByVal salesOrder As Integer, ByVal productRecNo As Integer, ByVal taskNumber As Integer, ByVal desc As String,
               ByVal enteredBy As String, enteredDate As Nullable(Of Date), ByVal completedDate As Nullable(Of Date), ByVal dispositionID As Integer, ByVal deptCodeID As Decimal)

    Try
        Me.SalesOrder = salesOrder
        Me.ProductRecordNumber = productRecNo
        Me.TaskNumber = taskNumber
        Me.Description = desc
        Me.EnteredBy = enteredBy
        Me.EnteredDate = enteredDate
        Me.CompletedDate = completedDate
        Me.DispositionID = dispositionID
        Me.DeptCodeID = deptCodeID
    Catch ex As Exception
        MessageBox.Show(ex.Message, "New_Event", MessageBoxButton.OK, MessageBoxImage.Error)
    End Try
End Sub
End Class

Public Class QCItems
Implements INotifyPropertyChanged

Private _qcItem As ICollection(Of QCItem)
Public Property QCItem As ICollection(Of QCItem)
    Get
        Return _qcItem
    End Get
    Set(value As ICollection(Of QCItem))
        _qcItem = value

        OnPropertyChanged(New PropertyChangedEventArgs("QCItem"))
    End Set
End Property

Public Sub New()
    Me.QCItem = New ObservableCollection(Of QCItem)
End Sub

Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
    If Not PropertyChangedEvent Is Nothing Then
        RaiseEvent PropertyChanged(Me, e)
    End If
End Sub
End Class

ANSWER (thanks to bars222):

<TextBlock x:Name="txtDisposition" Text="{Binding DispositionID, Converter={StaticResource qcDispCvrt}, UpdateSourceTrigger=PropertyChanged}" />

Public Class QCDescConverter
Implements IValueConverter

Public Function Convert(value As Object, targetType As Type, parameter As Object, culture As System.Globalization.CultureInfo) As Object Implements IValueConverter.Convert
    Try
        If value IsNot Nothing AndAlso value.ToString().Length > 0 Then
            Dim iVal As Integer = System.Convert.ToInt32(value)
            Dim util As New DBUtil
            Dim returnVal As String

            returnVal = util.GetDefectDesc(iVal)

            Return returnVal
        End If

        Return Nothing
    Catch ex As Exception
        Return Nothing
        MessageBox.Show(ex.Message, "Insert Note Failed", MessageBoxButton.OK, MessageBoxImage.Error)
    End Try
End Function

Public Function ConvertBack(value As Object, targetType As Type, parameter As Object, culture As System.Globalization.CultureInfo) As Object Implements IValueConverter.ConvertBack
    Throw New NotImplementedException()
End Function
End Class

Answer 1

You observe DispositionID in the Disposition column, cause you have CellTemplate with txtDisposition that displayed this.

To display DefectDesc you can add ValueConverter to the txtDisposition binding that converts id to DefectDesc.

Or you can add DefectDesc property in QC class for displaying that description. And you should add code in the DispositionID property setter, that updates DefectDesc. And change txtDisposition binding to DefectDesc.