C# Databound Windows Forms control does not retain value unless you leave the field

Question

I saw the answer in Databound Windows Forms control does not recognize change until losing focus.

But this doesn't fully answer the question for me. I have the exact same situation. On ToolStrip_click, I go through all of my controls and I force "WriteValue()", but it still reverts to the previous value before the save. Can anyone suggest how I can fix this? Did I implement this incorrectly?

(See code for current (non-working) solution.)

private void menuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
{
    // Make sure that all items have updated databindings.
    foreach (Control C in this.Controls)
    {
        foreach (Binding b in C.DataBindings)
        {
            // Help: this doesn't seem to be working.
            b.WriteValue();
        }
    }
}

The code is now much simpler, but it is a considerable hack. I'd be very happy to know if there is a more "proper" fix for this.

private void menuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
{
    // Make sure that all text fields have updated by forcing everything
    // to lose focus except this lonely little label.
    label44.Focus();
}

Answer 1

The problem is probably that your databound controls are set to update on validation.

You need to set the DataSourceUpdateMode of each of the databound controls to DataSourceUpdateMode.OnPropertyChanged. For example, a databound textbox:

this.textBox1.DataBindings.Add(new System.Windows.Forms.Binding("Text", 
    this.someBindingSource, "SomeProperty", true, 
    System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));

You can also set the datasource update mode in the designer by :

Selecting the control and going to the Property Window -> (DataBindings) -> (Advanced)

-> Set the [Data Source Update Mode] in the dropdownlist to OnPropertyChanged.

cheers

Answer 2

A ToolStripButton does not take the Focus when clicked. You could add some code to (temporarily) focus another control. You can Focus a Label (as a neutral dummy).