How to bind DataGrid column width to column width of parent grid

Question

I have a fairly complex financial report with a number of headers and summarizing footers and with tabular data inbetween. Here is what is supposed to look like:

The topmost container of the page is a Grid whose columns should automatically adjust when the page is resized. In this Grid all headers and summary fields are contained. Inbetween is a DataGrid that is supposed to hold the detailed financial data and of course I need to have the column width of it's columns the same size as those of the Grid. My problem is that I am not able to bind the width of the DataGrid columns to the width of the enclosing DataGrid. Here is the code:

        <Grid x:Name="gridKonsolidiert" 
          Grid.Row="1"
          HorizontalAlignment="Stretch"
          Margin="0,0,9,0">

        <Grid.RowDefinitions>
            <RowDefinition Height="28" />
            <RowDefinition Height="28" />
            <RowDefinition Height="22" />
            <RowDefinition Height="*" />
            <RowDefinition Height="22" />
            ....
        </Grid.RowDefinitions>

        <Grid.ColumnDefinitions>
            <ColumnDefinition x:Name="gcolEADatum" Width="50*" />
            <ColumnDefinition x:Name="gcolEinBtto20"  Width="60*" />
            <ColumnDefinition x:Name="gcolEinUSt20"  Width="60*" />
            <ColumnDefinition x:Name="gcolEinNtto20"  Width="60*" />
            ....
        </Grid.ColumnDefinitions>

        <DataGrid x:Name="dgvKonsolidiert"
                  Grid.Row="3"
                  Grid.Column="0"
                  Grid.ColumnSpan="21"
                  Focusable="True"
                  Width="{Binding ElementName=gridKonsolidiert, Path=ActualWidth}"
                  ItemsSource="{Binding KonsolidiertCol, Mode=OneWay}"
                  IsSynchronizedWithCurrentItem="True"
                  AlternationCount="2"
                  AlternatingRowBackground="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"
                  SelectionMode="Single"
                  SelectionUnit="FullRow"
                  AutoGenerateColumns="False"
                  GridLinesVisibility="None"
                  VerticalAlignment="Stretch"
                  HorizontalAlignment="Stretch"
                  RenderTransformOrigin="0.5,0.5"
                  CanUserAddRows="False"
                  HeadersVisibility="Column"
                  VerticalScrollBarVisibility="Hidden"
                  HorizontalScrollBarVisibility="Disabled"
                  CanUserReorderColumns="False"
                  CanUserResizeColumns="False"
                  CanUserResizeRows="False"
                  RowDetailsVisibilityMode="Visible"
                  BorderThickness="1"
                  BorderBrush="{StaticResource DataGridBorderColor}"
                  IsReadOnly="True"
                  Margin="0,2,0,20"
                  Grid.RowSpan="2">

            <DataGrid.Columns>

                <DataGridTextColumn x:Name="colEADatum"
                                    Header="Datum"
                                    HeaderStyle="{StaticResource DataGridHeaderCentered_BorderRight}"
                                    CellStyle="{StaticResource DataGridCellCentered_BorderRight}"
                                    Width="{Binding ElementName=gcolEADatum, Path=ActualWidth, diag:PresentationTraceSources.TraceLevel=High}"
                                    Binding="{Binding Path=EADatum, StringFormat=dd.MM}"
                                    TextBlock.LineHeight="24">
                </DataGridTextColumn>
                <DataGridTextColumn x:Name="colEinBtto20"
                                    Header="Brutto"
                                    HeaderStyle="{StaticResource DataGridHeaderRightAligned}"
                                    Width="60*"
                                    CellStyle="{StaticResource DataGridCellRightAligned}"
                                    Binding="{Binding Path=EinBtto20, StringFormat={StaticResource fmtNumberOrEmpty}}">
                </DataGridTextColumn>
                <DataGridTextColumn x:Name="colEinUSt20"
                                    Header="USt"
                                    HeaderStyle="{StaticResource DataGridHeaderRightAligned}"
                                    Width="60*"
                                    CellStyle="{StaticResource DataGridCellRightAligned}"
                                    Binding="{Binding Path=EinUSt20, StringFormat={StaticResource fmtNumberOrEmpty}}">
                </DataGridTextColumn>
                ....
            </DataGrid.Columns>
        </DataGrid>

The diagnose in Output Window then states:

    System.Windows.Data Warning: 56 : Created BindingExpression (hash=58206383) for Binding (hash=58663159)
    System.Windows.Data Warning: 58 :   Path: 'ActualWidth'
    System.Windows.Data Warning: 60 : BindingExpression (hash=58206383): Default mode resolved to OneWay
    System.Windows.Data Warning: 61 : BindingExpression (hash=58206383): Default update trigger resolved to PropertyChanged
    System.Windows.Data Warning: 62 : BindingExpression (hash=58206383): Attach to System.Windows.Controls.DataGridTextColumn.Width (hash=48266778)
    System.Windows.Data Warning: 64 : BindingExpression (hash=58206383): Use Framework mentor <null>
    System.Windows.Data Warning: 67 : BindingExpression (hash=58206383): Resolving source 
    System.Windows.Data Warning: 69 : BindingExpression (hash=58206383): Framework mentor not found
    System.Windows.Data Warning: 65 : BindingExpression (hash=58206383): Resolve source deferred
    'EARechnung_C.exe' (CLR v4.0.30319: EARechnung_C.exe): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\PresentationFramework.resources\v4.0_4.0.0.0_de_31bf3856ad364e35\PresentationFramework.resources.dll'. Module was built without symbols.
    System.Windows.Data Warning: 67 : BindingExpression (hash=58206383): Resolving source 
    System.Windows.Data Warning: 69 : BindingExpression (hash=58206383): Framework mentor not found
    'EARechnung_C.exe' (CLR v4.0.30319: EARechnung_C.exe): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Resources.ResourceManager\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Resources.ResourceManager.dll'. Cannot find or open the PDB file.
    System.Windows.Data Warning: 79 : BindingExpression (hash=58206383): Deactivate
    System.Windows.Data Warning: 63 : BindingExpression (hash=58206383): Detach

I hope there is anybody that can help me with that problem.

DataGridColumns are not part of Visual Tree so binding won't work. You need to do a work around. Plenty of examples over the internet. — Nikhil Agrawal, Jul 25 '17 at 08:52
It would be helpfull if you could send me a link to one of those examples, Nikhil. Cheers — pb_SKAT, Jul 25 '17 at 09:04
https://stackoverflow.com/questions/22073740/binding-visibility-for-datagridcolumn-in-wpf — Nikhil Agrawal, Jul 25 '17 at 09:14
Thanks Nikhil. The example is about how to bind the visibility of a DataGrid column to something. What I need is to bind is the width of a DataGrid column to the width of a Grid column where the Grid is parent of the DataGrid. I can't see how to apply that example to my problem. Could you please give me same more explanation? — pb_SKAT, Jul 25 '17 at 11:27

score 2 · Answer 1 · edited Jul 25 '17 at 15:58

Based on Nikhil's example and his hint "DataGridColumns are not part of Visual Tree".

I did the following: I added a last header row and defined the column headers of the DataGridColumns as borders with TextBlock and a name, e.g. x:Name="gcolEADatum". The DataGrid has the property HeadersVisibility="None" and each DataGridColumn now references the actual width of its header through Width="{Binding Source={x:Reference gcolEADatum}, Path=ActualWidth}.

This now works as expected, i.e. if the page is resized the grid columns and the datagrid columns both resize properly.

How to bind DataGrid column width to column width of parent grid

1 Answers1