WPF adding stackpanel with border to grid gives error - wpf

Question

I'm working on a nested grid/stackpanel/grid window in WPF. Its a Calander, with a maingrid cell being a day. In this day there's a textbox and a stackpanel. The stackpanel contains a grid. EVerything is done in c#, build at run time, because the layout changes with the current month/year. No major problems sofar except when I want to add a border to a stackpanel. It gives the following error:
An unhandled exception of type 'System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll
Additional information: 'The invocation of the constructor on type 'ADBF.ToezAcad.Admin.OpleidingKalender.MainWindow' that matches the specified binding constraints threw an exception.' Line number '3' and line position '9'.
Nothing special at this position.
Funny thing is it only gives this error, the moment I add the stackpanel ( with border ) to the containing grid.
short version of the code:
Border stackpanelborder = new Border();
this.Content = stackpanelborder;
StackPanel stackpanel = new StackPanel();
stackpanelborder.Child = stackpanel;
Grid.SetColumn(stackpanel, m);
Grid.SetRow(stackpanel, d + 1);
mainGrid.Children.Add(stackpanel); // if I uncomment this line, it throws the error.
Any help would be highly appreciated,
Arnold

Answer 1

#ADBF you are adding the StackPanel to two different child collections. Each UIElement should only have one parent in the visual tree, though a UIElement may have many children, depending on it's type.
I think you wanted to add stackpanelborder to the children of the mainGrid instead.
Edit:
Also you should be referencing stackpanelborder in the SetColumn/SetRow Methods not stackpanel.
The reason being since stackpanel is a child of stackpanelborder it will render inside the that UIElement. However stackpanelborder needs to be told where to insert in the grid, assuming you intend to add additional columns/rows later.
Basically your XAML document if you had one should look like this:
<Grid Name="mainGrid">
<Grid.ColumnDefinitions>
<ColumnDefinition .../>
<ColumnDefinition .../>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition .../>
<RowDefinition .../>
</Grid.RowDefinitions>
<Border Name="stackpanelborder" Grid.Row="0" Grid.Column="0" ...>
<StackPanel Name="stackpanel" .../>
</Border>
</Grid>