Question

Does anybody know what’s kind of event happend on target control when I use errorProvider.SetIconAlignment() method?

for example:

When I call errorProvider.SetIconAlignment(mytextbox1, ErrorIconAlignment.MiddleRight);

on mytextbox1 I want to catch this event whenever SetIconAlignment was called?

Answer 1

I don’t see an event that ErrorProvider could be using. In fact, I can’t find any event at all that’s related to this.

Based on what I’ve used from ErrorProvider, there is no other way than to extend the method, like this:

// Defines an extended version of the ErrorProvider
public class ExtendedErrorProvider : ErrorProvider, INotifyPropertyChanging, INotifyPropertyChanged
{
    // That will replace the SetIconAlignment from the base class when you call it from outside the class
    public void SetIconAlignment(Control control, ErrorIconAlignment value)
    {
        // Will raise an event just before changing the property
        OnPropertyChanging("IconAlignment");
        // Changed the property using the base class
        base.SetIconAlignment(control, value);
        // Will raise an event just after the property has changed
        OnPropertyChanged("IconAlignment");
    }

    // This will ensure that whenever you bind methods to be called on the PropertyChanging, they will get called for the specific property...
    protected void OnPropertyChanging(string property) { if (PropertyChanging != null) PropertyChanging(this, new PropertyChangingEventArgs(property)); }
    public event PropertyChangingEventHandler PropertyChanging;
    // This will ensure that whenever you bind methods to be called on the PropertyChanged, they will get called for the specific property...
    protected void OnPropertyChanged(string property) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(property)); }
    public event PropertyChangedEventHandler PropertyChanged;
}

Now, outside this class, you can do something like this:

errorProvider1.PropertyChanging += WhatNeedsToBeDoneBeforeChanging(...);
errorProvider1.PropertyChanged += WhatNeedsToBeDoneAfterChanging(...);