By default, the C1DateTimePicker control doesn't allow users to enter null values, but you can force the control to accept a null value by setting the C1DateTimePicker.AllowNull property to True. In this topic, you will learn how to set the AllowNull property to True in the designer, in XAML, and in code.

In the Designer

Complete the following steps:

1. Click the C1DateTimePicker control once to select it.
2. In the Properties window, select the C1DateTimePicker.AllowNull check box.

In XAML

To allow null values, place AllowNull="True" to the <my:C1DateTimePicker> tag so that the markup resembles the following:

<my:C1DateTimePicker AllowNull="True"/>

In Code

Complete the following steps:

1. Open the Window1.xaml.cs page.
2. Place the following code beneath the InitializeComponent() method:

   Visual Basic	Copy Code
   C1DateTimePicker1.AllowNull = True

   C#	Copy Code
   c1DateTimePicker1.AllowNull = true;

3. Run the project.