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## ASP.NET Calendar SelectedDate Property The `SelectedDate` property is a core feature of the ASP.NET Web Forms `Calendar` control. It is used to get or set the currently selected date on the calendar. --- ## Definition and Usage The `SelectedDate` property allows developers to programmatically determine which date a user has clicked, or to pre-select a specific date when the page loads. * **Default Value:** `DateTime.MinValue` (which represents `01/01/0001 00:00:00`). * **Behavior:** If multiple dates are selected (when `SelectionMode` is set to `DayWeek` or `DayWeekMonth`), the `SelectedDate` property returns the first date in the selected range. --- ## Syntax ### ASP.NET Markup (Declarative Syntax) ```asp ``` ### C# (Code-Behind) ```csharp // Get the selected date DateTime selected = Calendar1.SelectedDate; // Set the selected date Calendar1.SelectedDate = new DateTime(2023, 10, 25); ``` ### VB.NET (Code-Behind) ```vb ' Get the selected date Dim selected As DateTime = Calendar1.SelectedDate ' Set the selected date Calendar1.SelectedDate = New DateTime(2023, 10, 25) ``` --- ## Code Examples ### Example 1: Displaying the Selected Date (VB.NET) The following example demonstrates how to capture the `SelectionChanged` event and output the selected date to the user using VB.NET. ```asp

``` ### Example 2: Displaying the Selected Date (C#) This is the equivalent implementation using C# and a Label control to display the selected date cleanly. ```asp <%@ Page Language="C#" %>

Select a Date:

``` --- ## Key Considerations 1. **Date Range Selection:** If you allow users to select multiple dates (e.g., a whole week or month), use the `SelectedDates` collection property instead of `SelectedDate`. `SelectedDate` will only return the first date of that collection. 2. **Clearing Selection:** To clear the selected date programmatically, you can clear the `SelectedDates` collection: ```csharp Calendar1.SelectedDates.Clear(); ``` 3. **Initial Value:** If no date is selected by the user and you have not set one programmatically, `SelectedDate` returns `01/01/0001`. It is good practice to check if a date has been selected before processing it: ```csharp if (Calendar1.SelectedDate != DateTime.MinValue) { // Process the date } ```