[RESOLVED] Binding Datatable image column to Datagrid column

[JayJayson]

Hello,

I have just started my first project with WPF and looking at how I can bind a Datatable to a Datagrid. I can see that my text column binds properly but that an image column within the Datatable does not show my images in the Datagrid.

Here is the XAML I am using:

<DataGrid x:Name="grdImage" Grid.Column="0" AutoGenerateColumns="False" CanUserAddRows="False" BorderThickness="0,1,1,1" ItemsSource="{Binding}">
    <DataGrid.Columns>
        <DataGridTemplateColumn Width="SizeToCells" IsReadOnly="True">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Image Source="{Binding colImage}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <DataGridTextColumn Header="Image Filename" Width="*" Binding="{Binding colPath}"/>
    </DataGrid.Columns>
</DataGrid>

And this is the code I am using in the editor:

#Region " Properties "

  Public Property ImageCollection As DataTable
    Get
      Return TryCast(Me.grdImage.DataContext, DataTable)
    End Get
    Set(value As DataTable)
      Me.grdImage.DataContext = value
    End Set
  End Property

#End Region

#Region " Buttons "

  Private Sub btnOpenFile_Click(sender As Object, e As RoutedEventArgs) Handles btnOpenFile.Click
    Dim oFile As New OpenFileDialog
    With oFile
      .Title = "Select image(s) to resize"
      .InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
      .Multiselect = True
    End With
    If oFile.ShowDialog() Then
      Dim T As New Thread(AddressOf Me.ImportImages)
      T.Start(New ImportImagesArguments With {
              .ImportMode = ImportImagesArguments.Mode.SelectedFiles,
              .RootFolder = oFile.InitialDirectory,
              .ImagePaths = oFile.FileNames})
    End If
  End Sub

#End Region

#Region " Classes "

  Public Class ImportImagesArguments
    Public Enum Mode
      AllFilesInFolder
      AllFilesInFolderWithRecursion
      SelectedFiles
    End Enum

    Public Property ImportMode As Mode
    Public Property RootFolder As String
    Public Property ImagePaths As String()
    Public Property ImageTable As DataTable
  End Class

#End Region

#Region " Private Methods "

  Private Function LoadImageThumbnail(ByVal ImagePath As String, Optional ThumbSize As Integer = 32) As Image
    Dim Callback As New Image.GetThumbnailImageAbort(AddressOf ThumbnailCallback)
    Dim SrcBMP As New Bitmap(ImagePath)
    If SrcBMP.Width < ThumbSize Then
      ThumbSize = SrcBMP.Width
    End If
    If SrcBMP.Height < ThumbSize Then
      ThumbSize = SrcBMP.Height
    End If
    Return SrcBMP.GetThumbnailImage(ThumbSize, ThumbSize, Callback, IntPtr.Zero)
  End Function

  Private Function ThumbnailCallback() As Boolean
    Return False
  End Function

#End Region

#Region " Threading "

  Private Sub ImportImages(state As Object)
    Dim Args As ImportImagesArguments = CType(state, ImportImagesArguments)
    Args.ImageTable = New DataTable
    Args.ImageTable.Columns.Add("colImage", GetType(Image))
    Args.ImageTable.Columns.Add("colPath", GetType(String))
    For Each ImgPath As String In Args.ImagePaths
      Dim DRow As DataRow = Args.ImageTable.NewRow
      DRow.Item("colImage") = Me.LoadImageThumbnail(ImgPath)
      DRow.Item("colPath") = ImgPath
      Args.ImageTable.Rows.Add(DRow)
    Next ImgPath
    Me.ImportImagesComplete(Args)
  End Sub

  Private Delegate Sub DEL_ImportImagesComplete(state As Object)
  Private Sub ImportImagesComplete(state As Object)
    If Not Dispatcher.CheckAccess Then
      Dispatcher.Invoke(New DEL_ImportImagesComplete(AddressOf Me.ImportImagesComplete), New Object() {state})
    Else
      Dim Args As ImportImagesArguments = CType(state, ImportImagesArguments)
      Me.ImageTable = Args.ImageTable
      Me.ImageCollection = Args.ImageTable
    End If
  End Sub

#End Region

I have found a lot of examples via Google that demonstrate how to bind an image to a static resource or to an image based upon it's filepath, however I am struggling to find an example that shows how I can bind to images either within a Collection or a Datatable where the image has already been loaded into memory.

Any help on this would be appreciated.

Thanks,
Jay

[JayJayson]

After some further reading I have realised that a System.Drawing.Image cannot be bound to a System.Windows.Controls.Image used in WPF. The solution I found is to create an IValueConverter class, add it as a local resource to the XAML and then specify the converter in the Source binding of the image column within my DataGrid. When testing with my original code it seems to work as expected.

The code for these additions is as follows (in case anybody else finds it useful):

XAML added within the Window element:

<Window.Resources>
    <local:BitmapToImageSourceConverter x:Key="BitmapToImageConverter" />
</Window.Resources>

My updated Image Binding within the DataGrid XAML:

<Image Source="{Binding colImage, Converter={StaticResource BitmapToImageConverter}}"/>

And finally the class for the image conversion which sits outside of the MainWindow class in the code editor:

Public Class BitmapToImageSourceConverter : Implements IValueConverter

  Public Function Convert(value As Object, targetType As Type, parameter As Object, culture As CultureInfo) As Object Implements IValueConverter.Convert
    Return Interop.Imaging.CreateBitmapSourceFromHBitmap(
        CType(value, Bitmap).GetHbitmap,
        IntPtr.Zero,
        Int32Rect.Empty,
        BitmapSizeOptions.FromEmptyOptions)
  End Function

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

End Class

Regards,
Jay