Forums Ultimate UI for WPF
Your Privacy Matters: We use our own and third-party cookies to improve your experience on our website. By continuing to use the website we understand that you accept their use. Cookie Policy
Close
Karl-Michael
515
How to get cell from DataContext for CellValuePresenter
posted

Hi,

i followed your post to write a custom cell presenter control:

  <igDP:XamDataGrid Name="DataGrid"  >
                <igDP:XamDataGrid.Resources>
                    <Style x:Key="CellStyle" TargetType="{x:Type igDP:CellValuePresenter}">
                        <Setter Property="Template">
                            <Setter.Value>
                                <ControlTemplate TargetType="{x:Type igDP:CellValuePresenter}">    
                                    <StackPanel Orientation="Horizontal">
                                        <!--<Label Content="{TemplateBinding DataContext}"  Width="{TemplateBinding Width}" Height="{TemplateBinding Height}"></Label>-->
                                        <my:CWpfIgZelleGui
                                            DataContext="{TemplateBinding DataContext}" 
                                            Width="{TemplateBinding Width}"
                                            Height="{TemplateBinding Height}"
                                            />
                                       
                                    </StackPanel>
                                </ControlTemplate>
                            </Setter.Value>
                        </Setter>
                    </Style>
                </igDP:XamDataGrid.Resources>
            </igDP:XamDataGrid>

In the code i set the style and my cell control is displayed.

But the problem is with the datacontext:

The datacontext contains the DataRecord. How should i figure out, which cell to display?

 

 

 

 

 

 

Parents
No Data
Reply
  • 515
    Suggested Answer
    posted

    Ok, i made a workouround:

    [1] I added a DependencyProperty 'Field' to CWpfIgCellGui-control

    ' [2] I created a celltemplate in the codebehind for each Cell

    ' [3] in the template i assigned the field to the property

    [4] in CWpfIgCellGui i added another datacontext which i set to the cell which i can determine by evaluating [5] the datacontext for the control (which points to datarecord) and the field from my own dependency property.

    that is quite sophisticated to realize a standard usecase (and i guess displaying a cell value in a cellvaluepresenter should be a standard use case) so i hope there is a better solution. (The solution for my understanding would be that the data context contains the cell, not the record)

    here's the code:

    ' [1] I added a DependencyProperty 'Field' to CWpfIgCellGui-control

         Public Shared ReadOnly FieldProperty As DependencyProperty = DependencyProperty.Register("Field", GetType(Field), GetType(CWpfIgZelleGui), New PropertyMetadata(AddressOf FieldChanged))
        Public Property Field() As Field
            Get
                Return DirectCast(Me.GetValue(FieldProperty), Field)
            End Get
            Set(ByVal value As Field)
                Me.SetValue(FieldProperty, value)
            End Set
        End Property

    ' [2] I created a celltemplate in the codebehind for each Cell

            Dim aField As New UnboundField       
            Dim aCellStyle As New Style
            aCellStyle.TargetType = GetType(CellValuePresenter)
            Dim aTemplateSetter As New Setter
            aTemplateSetter.Property = CellValuePresenter.TemplateProperty
            Dim aTemplate As New ControlTemplate(GetType(CellValuePresenter))
            Dim aTemplateElementFactory As New FrameworkElementFactory(GetType(CWpfIgZelleGui))
            aTemplateElementFactory.SetValue(CWpfIgZelleGui.FieldProperty, aField) ' ' [3] in the template i assigned the field to the property 
            aTemplate.VisualTree = aTemplateElementFactory
            aTemplate.Seal()
            aTemplateSetter.Value = aTemplate
            aCellStyle.Setters.Add(aTemplateSetter)
            aField.Settings.CellValuePresenterStyle = aCellStyle
            aField.Name = Me.UnboundFieldName
            aField.DataType = GetType(Integer) 

     ' [4]

        Private Sub CWpfIgZelleGui_DataContextChanged(ByVal sender As Object, ByVal e As System.Windows.DependencyPropertyChangedEventArgs) Handles Me.DataContextChanged
            Me.GridDataContextFüllen()
        End Sub
         Private Shared Sub FieldChanged(ByVal d As System.Windows.DependencyObject, ByVal e As System.Windows.DependencyPropertyChangedEventArgs)
            DirectCast(d, CWpfIgZelleGui).GridDataContextFüllen()
        End Sub

        Private Sub GridDataContextFüllen()
            Dim aField As Field = Me.Field
            Dim aRecord As DataRecord = DirectCast(Me.DataContext, DataRecord)
            Dim aCell As Cell
            If aRecord IsNot Nothing And aField IsNot Nothing Then
                aCell = aRecord.Cells(aField) ' [5] evaluating the cell which we need to display the cell value.
            Else
                aCell = Nothing
            End If
            Me.GridM.DataContext = aCell
        End Sub

     

Children