Default Theme
All RadControls from the Telerik UI for WinForms suite get the ControlDefault theme applied to them by default if no other theme is set.
ControlDefault theme
If you drag a control from the toolbox and drop it onto the form, the ControlDefault theme is applied as well.
Design time - default theme
Using the built-in themes that come out of the box with the installation of the Telerik UI for WinForms suite, you can apply a different theme for the specific control.
Fluent theme as Default
As of R1 2021, it is possible to define which theme is your default theme (e.g. ControlDefault) for the controls even at design time. This can be defined in the App.config file as follows:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<appSettings>
<add key="TelerikWinFormsThemeName" value="Fluent" />
</appSettings>
</configuration>
Fluent theme as default
The Fluent theme is now a part of the Telerik.WinControls assembly and it is statically available everywhere just like the ControlDefault theme. As a result, it is no longer necessary to instantiate the FluentTheme type.
The Telerik.WinControls.Themes.Fluent assembly is still available and it remains for compatibility so that existing projects don't break when they upgrade.
The theme settings are being read upon opening the first form designer in the project. If you change the default theme in App.config, it is necessary to close all opened designers and open them again.
We are using the above App.config in the VS templates, so that new Telerik projects created by the Visual Studio extension have the Fluent theme set as default.
Other Telerik theme as Default
All Telerik themes are supported with the above API, it is, however, necessary that the project references the correct assembly, e.g. add reference to Telerik.WinControls.Themes.Material and in the App.config set:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<appSettings>
<add key="TelerikWinFormsThemeName" value="Material" />
</appSettings>
</configuration>
If the user sets a valid Telerik theme name (other than Fluent and ControlDefault) as default, but the project misses the theme assembly reference, the following message appears:
Once the necessary assembly is referred, the designer loads with the correct design:
In order to use the Theme components, just drag and drop them from the VS Toolbox to the form. This will add a reference to the corresponding theme assembly in the project and will enable the theme in the ThemeName drop-down of all Telerik controls on the form.
Custom theme as Default
Since it is possible to build your own custom style, it is possible to specify this theme as default. We will use the same API to load client's themes defined in their own assemblies: Creating a theme component
With the 2024 Q2 version of our controls it is necessary to use the assembly fully qualified name when defining it inside the App.config.
Imagine a client creates a theme with name LightCoral. Besides the theme name, the App.config will also need the theme type and theme assembly name.
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<appSettings>
<add key="TelerikWinFormsThemeName" value="LightCoral" />
<add key="TelerikWinFormsThemeType" value="LightCoralClassLibrary.LightCoralTheme"/>
<add key="TelerikWinFormsThemeAssemblyName" value="LightCoralClassLibrary, Version=1.0.0.0, Culture=neutral, PublicKeyToken=9aa2a467bbfe794e"/>
</appSettings>
</configuration>
Thus, if you drag a new RadButton from the Toolbox, it will be with the LightCoral theme applied.