Why doesnt DataBindings with the DateTimePicker always work

I have a weird problem with databindings and the datetimepicker in C# (winforms). Or at least I think it is weird.

I got a WinForm and on it I placed two DateTimePickers, one named BeginDatePicker, another one named EndDatePicker.

I also got a viewModel which has 2 properties declared:

Code:

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private DateTime _beginDate;
    private DateTime _endDate;

    public DateTime BeginDate
    {
        get
        {
            return _beginDate;
        }
        set
        {
            if (value != _beginDate) //I have a breakpoint here, bp1
            {
                _beginDate = value;
                RaisePropertyChanged(Utilities.GetNameOfProperty(() => BeginDate));
            }
        }
    }

    public DateTime EndDate
    {
        get
        {
            return _endDate;
        }
        set
        {
            if (value != _endDate) //I have a breakpoint here: pb2
            {
                _endDate = value;
                RaisePropertyChanged(Utilities.GetNameOfProperty(() => EndDate));
            }
        }
    }

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I put 2 breakpoints on the places marked in the code sample above (bp1 and bp2).

Next step is binding the properties to the DateTimePicker. I do that with the next code:

Code:

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            BeginDatePicker.DataBindings.Add(Utilities.GetNameOfProperty(() => BeginDatePicker.Value),
                                            _viewModel, Utilities.GetNameOfProperty(() => _viewModel.BeginDate));

            EndDatePicker.DataBindings.Add(Utilities.GetNameOfProperty(() => EndDatePicker.Value),
                                            _viewModel, Utilities.GetNameOfProperty(() => _viewModel.EndDate));

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When I run my program and I change the date in the BeginDatePicker, nothing happens (the code doesnt break at breakpoint pb1.) When I change the date in the EnddatePicker, something happens, the code does break at breakpoint pb2.

Why does the code not break at bp1 but it actually does break at bp2? I cannot figure out why. I checked it on typo's, I even write the code over again but no result.

the GetNameOfProperty Method is method I found on the internet:

Code:

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        public static string GetNameOfProperty<T>(Expression<Func<T>> variabeleAccessExpression)
        {
            var memberExpression = variabeleAccessExpression.Body as MemberExpression;
            return memberExpression.Member.Name;
        }

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Quote:

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Originally Posted by Cornelis

Next step is binding the properties to the DateTimePicker. I do that with the next code:

Code:

---

            BeginDatePicker.DataBindings.Add(Utilities.GetNameOfProperty(() => BeginDatePicker.Value),
                                            _viewModel, Utilities.GetNameOfProperty(() => _viewModel.BeginDate));

            EndDatePicker.DataBindings.Add(Utilities.GetNameOfProperty(() => EndDatePicker.Value),
                                            _viewModel, Utilities.GetNameOfProperty(() => _viewModel.EndDate));

---

Code:

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        public static string GetNameOfProperty<T>(Expression<Func<T>> variabeleAccessExpression)
        {
            var memberExpression = variabeleAccessExpression.Body as MemberExpression;
            return memberExpression.Member.Name;
        }

---

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Given how GetNameOfProperty works in the code above, your EndDatePicker.DataBindings.Add(...) calls are going to bind to the name of the method that calls them. Perhaps I'm wrong about this, but I would pull out the property retrieval code as a test and verify by setting a break point on the following line and make sure it is returning what I expect (i.e. the name of the property).

Code:

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var endDatePickerPropertyName = Utilities.GetNameOfProperty(() => EndDatePicker.Value);

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