TextBox in DataGrid EditTemplate not work properly when UpdateSourceTrigger is lost focus and column is always in editing mode

Hi Jason,

I have a datagrid that uses TextBox as the EditorTemplate for a column. If we set data binding's

UpdateSourceTrigger = UpdateSourceTrigger.LostFocus and set

column.IsAlwaysInEditMode = true (for some other reason, I need it to be always in edit mode)

then it will not update the data source after the cell lost focus (by clicking on other cell or other control).

The following are sample code:

public static DataTemplate EditTextBoxTemplate(string propertyName, bool isReadonly, HorizontalAlignment horizontalAlignment, TextAlignment textAlignment)
        {
            if (isReadonly)
            {
                return null;
            }
            Binding itemBinding = new Binding(propertyName);
            itemBinding.Mode = BindingMode.TwoWay;
            itemBinding.UpdateSourceTrigger = UpdateSourceTrigger.LostFocus; //UpdateSourceTrigger.LostFocus here will not work

            FrameworkElementFactory editFactory = new FrameworkElementFactory(typeof(TextBox));
            editFactory.SetBinding(TextBox.TextProperty, itemBinding);

            editFactory.SetValue(Control.BackgroundProperty, EditBackgroundBrush); // Set edit mode background

            editFactory.SetValue(VerticalAlignmentProperty, VerticalAlignment.Center);
            editFactory.SetValue(HorizontalAlignmentProperty, horizontalAlignment);
            editFactory.SetValue(VerticalContentAlignmentProperty, VerticalAlignment.Center);
            editFactory.SetValue(TextBox.TextAlignmentProperty, textAlignment);
            editFactory.SetValue(MarginProperty, new Thickness(1));

            DataTemplate editTemplate = new DataTemplate();
            editTemplate.VisualTree = editFactory;

            return editTemplate;
        }

I checked TextBox's LostFocus event and at this moment, the Text property is empty.

Please advise what should I do!

Thanks, Gordon

Hi Gordon,

Thanks for pointing this out. A possible fix for this will be available in the next nightly build. Let me know how it goes. Note that IsAlwaysInEditMode was a fairly experimental feature and if possible, may be best to avoid. I'll support it as best I can in cases that you really need to use it though.

-Jason Fauchelle

Hi Jason,

I downloaded the mar. 3, 2016 nightly build, and the problem is not fixed.

For some other reason, I do need it always in edit mode, i.e. in the image attached, I have a custom control contains a TextBox, and a button.

I want to put this control into datagrid, so the user can click on the button to browse for a file. If this column is not always in edit mode, then once the browsing file dialog is shown, the column is back to display mode. So the file we got cannot be set back to the textBox, since this custom control got unloaded already. So we cannot update back to the data source.

Thanks, Gordon

Hi Gordon,

I have not been able to reproduce this issue with my fix in place. I'll have another go next week. If you can send me a repro project, or example code similar to your custom control, then that would be a huge help to solving this.

-Jason Fauchelle

HI Jason,

The included is the reproducing project with textbox always in editor mode. It can reproduce the problem. It takes more time to have my custom control to put in the project

1. Unzip the project (we use 7zip to do the zipping)

2. Run the application

3. Click on button MoreProblem

4. First name and last name columns are always in edit mode.

5. edit first name or last name, then click on Age column cell, same record or different record, you will see the value you edited will not get updated into the source.

6. the other observation is that if you edit First Name and click on Last name column cell or vise visa, then the value gets updated into the source

If you really need to have my custom control in I can when I got some time.

Thanks, Gordon

Hi Gordon,

Thanks for the repro project. If I'm able to reproduce the issue with this, then I shouldn't need the custom control code - I had originally thought the existence of a custom control may be causing the issue.

I will let you know how it goes.

-Jason Fauchelle

Hi Gordon,

Thanks again for the repro project. I was able to reproduce the issue and have made fix to be available in the next nightly build.

-Jason Fauchelle

Hi Jason,

The problem is fixed. Thanks, Gordon