DataGrid Binding Problem

Kevin Marois

I'm trying to get a simple datagrid to work. I've been Googling and searching and can't figure this out. Entity

public class PurchaseOrderEntity : _EntityBase
{
private int _Quantity;
public int Quantity
{
get { return _Quantity; }
set
{
if (_Quantity != value)
{
_Quantity = value;
RaisePropertyChanged("Quantity");
}
}
}

private int \_SizeId;
public int SizeId
{
    get { return \_SizeId; }
    set
    {
        if (\_SizeId != value)
        {
            \_SizeId = value;
            RaisePropertyChanged("SizeId");
        }
    }
}

}

View Model

private List _PurchaseOrders;
public List PurchaseOrders
{
get { return _PurchaseOrders; }
set
{
if (_PurchaseOrders != value)
{
_PurchaseOrders = value;
RaisePropertyChanged("PurchaseOrders");
}
}
}

private PurchaseOrderEntity _SelectedPurchaseOrder;
public PurchaseOrderEntity SelectedPurchaseOrder
{
get { return _SelectedPurchaseOrder; }
set
{
if (_SelectedPurchaseOrder != value)
{
_SelectedPurchaseOrder = value;
RaisePropertyChanged("SelectedPurchaseOrder");
}
}
}

DataGrid

Lost User

SelectedItem="{Binding SelectedPurchaseOrder, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

99% of the population would use the selected item changed event handler. (and I would use a "form" for adding new records). (MVVM sucks again in this case)

"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

Mycroft Holmes

I think your List<> in the viewmodel should be an ObservableCollection<> I would also test it without the combobox in the grid (I NEVER allow complex controls in a data grid).

Never underestimate the power of human stupidity - RAH I'm old. I know stuff - JSOP

Kevin Marois

This is a heads up data entry form. The user needs to be able to enter a lot of data quickly. Stopping to grab the mouse is not really what they're looking for.

If it's not broken, fix it until it is. Everything makes sense in someone's mind. Ya can't fix stupid.

Kevin Marois

See my reply to Gerry

If it's not broken, fix it until it is. Everything makes sense in someone's mind. Ya can't fix stupid.

Lost User

Quote:

Stopping to grab the mouse is not really what they're looking for.

[How to implement Hot Keys in WPF?](https://social.msdn.microsoft.com/Forums/vstudio/en-US/0c9577dc-cf71-4631-bff9-c41ab6b0ea58/how-to-implement-hot-keys-in-wpf?forum=wpf) [Assigning Keyboard Shortcut / Access Keys to your WPF Application – Mohammed Jeelani's Blog](https://blogs.msdn.microsoft.com/mjeelani/2007/12/15/assigning-keyboard-shortcut-access-keys-to-your-wpf-application/) etc. (I though it was "heads-down")

"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

Kevin Marois

This feels like work arounds. I'll do an entry form is all else fails, but it has to be possible to do what I want. I've seen data entry grids before.

Gerry Schmitz wrote:

(I though it was "heads-down")

:) :)

If it's not broken, fix it until it is. Everything makes sense in someone's mind. Ya can't fix stupid.

Mycroft Holmes

But but a combobox is going to slow down data entry, an auto complete textbox might be better with some validation after they leave the control. I would try really hard to move the data entry to a panel instead of within the grid.

Never underestimate the power of human stupidity - RAH I'm old. I know stuff - JSOP

Lost User

You can do data entry in a data grid. You just wind up writing a lot more code and it gets very difficult to extend as soon as the user comes up with something weird. And, you're always sitting "at the bottom" when adding a new record. Combine the two: e.g. CTRL+N: pops up the form for a new record. PF5: pops up a form for the current record in grid (edit) CTRL+D: delete the current record in grid. CTRL+S: Save the current form / record (keep form open if in "data entry mode") ESC: release the form. Extra credits: Navigate in form. (Keyboard preview key down and handled at the "form" / window / user control level)

"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal

Richard Deeming

Looks like it's a known bug that dates back to 2009: Problems binding to SelectedValue with Microsoft’s WPF DataGrid | Nigel Spencer's Blog[^] c# - Bug in WPF DataGrid - Stack Overflow[^] The workaround seems to be to use a custom converter on the SelectedItem binding.

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer