Resources in WPF

Windows Presentation Foundation (WPF) resources provide a simple way to reuse commonly defined objects and values. Resources in WPF allow you to set the properties of multiple controls at a time. For example you can set the background property on several elements in a WPF application using a single resource.

The best way of defining the resources is on a Window or Page element level. Any resource that you define for an element also applies to their child elements of that element. For example if you define a resource for a Window element that has a Grid as a child element, then the resources defined for the window elements can also be used by the grid element. However, if you define a resource for the grid element, then the resource applies only to the child elements of the grid element.

Syntax for resources in WPF as follows

<elementName propertyName="{markupExtension keyName}">

<!-Content -->

</elementName>

elementName: Name of the element that uses the resource

propertyName: Name of the property that takes its value from the resource

markupExtension: Define type of resource

keyName: key name of the resource, which is unique string to identify the resource

There are two types of resource, namely

• Static Resource
• Dynamic Resource

Let's see basics of both resources

Static Resource

We should use the StaticResource markup extension to define the resource as a static resource. The value of StaticResource is determined at the time of loading.

Let's have a sample program, Add the below code snippet in Window1.xaml file inside the Grid

<Grid.Resources>

            <SolidColorBrush x:Key="lblbgcolor" Color="Blue"/>

        </Grid.Resources>

        <Label Name="lbl" Margin="71,44,77,0" Background="{StaticResource lblbgcolor}" Height="49" />

Above code, Grid control uses the Resources property (<Grid.Resources>) to define resource. SolidColorBrush resource named lblbgcolor defined. lblbgcolor resource is used to set the background property of lable.

Dynamic Resource

Dynamic Resource we use in a situation where we want to change the value of property at run time.

Let's have a sample program, Add the below code snippet in Window1.xaml file inside the Window element

<Window.Resources>

        <SolidColorBrush x:Key="brush" Color="Red" />

    </Window.Resources>

    <Button x:Name="btn" Content="Click Me" Click="Button_Click" Background="{DynamicResource brush}" Height="100" Width="100" />

Open Code behind and add the following code snippet

private void Button_Click(object sender, RoutedEventArgs e)

{

    this.btn.SetResourceReference(BackgroundProperty, "brush");

}

Above code, Window control uses the Resources property (<Window.Resources>) to define resource. SolidColorBrush resource named brush defined. brush resource is used to set the background property of button.

Conclusion

I have covered basics of resources in WPF. I hope this will helps all the beginners to startup.

Reference

Dreamtech: WPF in simple steps