How to cancel the ValueChanged event for NumericUpDown controls?

Question

Under certain conditions I'd like to cancel the ValueChanged event of a NumericUpDown control in Winforms (eg when the value set in the control is too high in relation to another value in a TextBox ).

However, the EventArgs passed as argument into the event handler for the NumericUpDown control doesn't offer anything like "Cancel", so how can I do it?

    private void nudMyControl_ValueChanged(object sender, EventArgs e)
    {
      // Do some stuff, but only if the value is within a certain range.
      // Otherwise, cancel without doing anything.
    }

Answer 1

You probably can handle this situation by using Minimum & maximum Properties, yet there are some solutions.

One way to do it is by creating a custom control, although it is nasty in my idea.

    public partial class CustomNumericUpDown : NumericUpDown
{
    public CustomNumericUpDown()
    {
        InitializeComponent();
    }

    protected override void OnTextBoxKeyDown(object source, KeyEventArgs e)
    {
        if (MyCustomCondition())
        {
            e.Handled = true;
        }
        base.OnTextBoxKeyDown(source, e);
    }

    private bool MyCustomCondition()
    {
        var checkOut = false;

        //if (something == foo)
        //{
            checkOut = true;
        //}

        return checkOut;
    }
}

You also can do stuff for ValueChanged :

This is some dummy sample, yet you can change it in your way:

    public virtual decimal CurrentEditValue { get; internal set; } = 0M;

    protected override void OnTextChanged(EventArgs e)
    {
        base.OnTextChanged(e);
        if (decimal.TryParse(Text, out decimal v))
        {
            CurrentEditValue = v;
            OnValueChanged(e);
        }
    }

    protected override void OnValueChanged(EventArgs e)
    {
        // if(CurrentEditValue == foo) Do_stuff.
        base.OnValueChanged(e);
    }