# Expand State

Expander is an expandable and collapsible information panel which appears in collapsed state initially. Learn more about the expand state in Expander for WPF documentation.

## Content

By default, the Expander control appears in collapsed state and the content area is not visible when the window is loaded. However, you can change the behavior of the control upon window load by setting [IsExpanded](/componentone/api/wpf/online-accordion5/dotnet-api/C1.WPF.Accordion/C1.WPF.Accordion.C1Expander.IsExpanded.html) property to **True**.

![Checkbox added to the content area of the Expander control](https://cdn.mescius.io/document-site-files/images/530ec557-536d-4b6e-94ca-c0cf743e2c3a/images/expander-checkbox-content.png)

The following example code demonstrates the use of **IsExpanded** property of the [C1Expander](/componentone/api/wpf/online-accordion5/dotnet-api/C1.WPF.Accordion/C1.WPF.Accordion.C1Expander.html) class to display the Expander control in expanded state. In this example, the IsExpanded property is set to true.

```xml
<c1:C1Expander x:Name="ExpanderControl" Header="Expand Me!" IsExpanded="True" FontFamily="Cambria" FontWeight="Bold" VerticalAlignment="Center" HorizontalAlignment="Center">
        <CheckBox Margin="10" VerticalAlignment="Center" x:Name="Condition" Content="CheckBox Inside Expander"/>
</c1:C1Expander>
```

```csharp
ExpanderControl.IsExpanded = true;
```