wpf-datepicker

xmlns:sys="clr-namespace:System;assembly=mscorlib"

<DatePicker x:Name="datePickerCtl" SelectedDate="{x:Static sys:DateTime.Now}"
SelectedDateFormat="Short" FirstDayOfWeek="Monday"
IsTodayHighlighted="True" Grid.Row="0" Grid.Column="1">
<DatePicker.Resources>
<Style TargetType="{x:Type DatePickerTextBox}">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<TextBox x:Name="PART_TextBox"
Text="{Binding Path=SelectedDate, StringFormat='yyyy-MM-dd',
RelativeSource={RelativeSource AncestorType={x:Type DatePicker}}}" />
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</DatePicker.Resources>
</DatePicker>


datePickerCtl.SelectedDate = DateTime.Now;

var strDate = datePickerCtl.SelectedDate.Value.ToString("yyyy-MM-dd");