为什么DatePicker的Text属性仍然包含值？

Question

I am building a WPF/C# application and I have several DatePicker-s which I reference using this construct:

for(int i = 0; i < n; i += 1)
{
    DatePicker dp = (DatePicker)this.FindName(Constants.DP_PRODUCT_PREFIX + (i + 1));
    dp.SelectedDate = new DateTime(2017, 12, 31);
    dp.IsEnabled = true;
    dp.Opacity = 1;
    dp.Text = "";
 }

However even if I set

dp.Text = "",

the DatePickers still show their textfield with 31/12/2017.

Note: I want my DatePicker to be set to a default value of my choosing which in this case is 31.12.2017

What do I do wrong? Is it maybe the time when I run this code, it doesn't apply the change?

Answer 1

You can find DatePickerTextBox in DatePicker Template(which displays SelectedDate value) to assign new value.The default name for DatePickerTextBox in Template was "PART_TextBox" so you can find it from Template like this

dp.Loaded += (ee, ss) =>
        {
            var template = dp.Template;
            var t = template.FindName("PART_TextBox", dp) as DatePickerTextBox;
            if (t != null)
                t.Text = "";
        };

put the code in Loaded event to make sure DatePickerTextBox is not null.You can also see DatePicker Template by right click on the control then select edit style.