topic Re: WPF with datagrid in Revit API Forum

WPF with datagrid

sonicer — Thu, 09 Jan 2020 09:49:40 GMT

Hello,

I am starting change Winform to WPF.

I have datagrid with abou 50 fields from Revit.

But I can't read some field currently invisible in datagrid. (visible when I scroll down)

TextBlock item= datagrid1.Columns[2].GetCellContent(datagrid1.Items[15]) as TextBlock;
            MessageBox.Show(item.Text);

this make error in revit...

but if I scroll to item 15 and click - it work correctly.

thanks..

Re: WPF with datagrid

jlpgy — Thu, 09 Jan 2020 10:06:47 GMT

Hi:

Here is my simple conclusion:

Your code is not MVVM.

Let's suppose that you have the cell that you are visiting has not yet been displayed on the screen (not yet rendered).

In WPF DataGrid control ( as well as most other controls), data won't be prepared before rendering.

Think abt it in another way. Bind DataGrid.ItemsSource property to a IEnumerable<T> collection property in your view model, then each single item has already been prepared whether the DataGrid control having been rendered or not.

The spirit of MVVM is that both the view and the view model can run without knowing each other.

Which means that you should *NEVER* visit DataGridCell.Content to get a TextBox.Text data. You should directly visit the collection property in you view model.

It's a gap for developers from WinForm 🙂

Re: WPF with datagrid

sonicer — Sat, 11 Jan 2020 22:24:15 GMT

thanks much

...thats look like as web system Joomla or Wordpress.

It so different Winform and WPF.