CODEWITHSUNDEEP
c#winformsdata-binding
Ivan-Mark Debono
Ivan-Mark Debono

Reputation: 16280

How to automatically set DataSourceUpdateMode in the designer?

I have a custom control with a two-way bindable property. I also raise a ValueChanged event on the value's setter.

For this type of custom control I need to change the DataSourceUpdateMode to OnPropertyChanged instead of the standard OnValidating.

As I'm doing all the data-binding within the designer, is it possible that the custom control set's the databinding to OnPropertyChanged once its added to the form?

EDIT:

Currently I'm doing this:

    protected override void OnCreateControl()
    {
        base.OnCreateControl();

        Binding binding = this.DataBindings[0] as Binding;
        if (binding != null)
        {
            binding.DataSourceUpdateMode = DataSourceUpdateMode.OnPropertyChanged;
        }
    }

Is this the correct way or is the OnBindingContextChanged a more suitable event?

Upvotes: 1

Views: 523

Answers (1)

Reza Aghaei
Reza Aghaei

Reputation: 125197

OnCreateControl is useless and OnBindingContextChanged is more suitable place to change DataBindings. Also instead of DataBindings[0] you should use a loop over DataBindings and if you want to apply the logic on a specific property, use an if statement to check PropertyName of Binding object:

protected override void OnBindingContextChanged(EventArgs e)
{
    foreach (Binding item in DataBindings)
    {
        if (item.PropertyName == "SomeProperty")
            item.DataSourceUpdateMode = DataSourceUpdateMode.OnPropertyChanged;
    }
    base.OnBindingContextChanged(e);
}

As an idea to apply such custom initialization tasks you can implement ISupportInitialize interface and put the logic which you want to apply when initialization completes in EndInit method.

Upvotes: 1

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