# File Explorer
## End user facing:
[Please visit our overview](https://aka.ms/PowerToysOverview_FileExplorerAddOns)
## Developing
We have already done most of the development work in the [PreviewHandlerCommon](./common/cominterop/IPreviewHandler.cs) common project. To add a preview for the file type of .xyz:
- Add a new .NET project in the preview pane folder.
- Add a reference to the `PreviewHandlerCommon` common project.
- Create your preview handler class and extend the FileBasedPreviewHandler class. See an example below:
```csharp
using System;
using System.Runtime.InteropServices;
using Common;
namespace XYZPreviewHandler
{
///
/// Implementation of preview handler for .xyz files.
/// GUID = CLSID / CLASS ID.
///
[Guid("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx")]
[ClassInterface(ClassInterfaceType.None)]
[ComVisible(true)]
public class XYZPreviewHandler : FileBasedPreviewHandler
{
private XYZPreviewHandlerControl xyzPreviewHandlerControl;
/// Call your rendering method here.
public override void DoPreview()
{
this.xyzPreviewHandlerControl.DoPreview(this.FilePath);
}
protected override IPreviewHandlerControl CreatePreviewHandlerControl()
{
this.xyzPreviewHandlerControl = new xyzPreviewHandlerControl();
return this.xyzPreviewHandlerControl;
}
}
}
```
Create a separate Preview Handler Control class and extend the `FormHandlerControl` Class.
```csharp
using Common;
namespace XYZPreviewHandler
{
public class XYZPreviewHandlerControl : FormHandlerControl
{
public XYZPreviewHandlerControl()
{
// ... do your initializations here.
}
public override void DoPreview(T dataSource)
{
// ... add your preview rendering code here.
}
}
}
```
#### Integrate the Preview Handler into PowerToys Settings:
Navigate to the [powerpreview](../previewpane/powerpreview/powerpreview.h) project and edit the `powerpreview.h` file. Add the following Settings Object instance to `m_previewHandlers` settings objects array in the constructor initialization:
```cpp
// XYZ Preview Handler Settings Object.
FileExplorerPreviewSettings(
false,
L"<--YOUR_TOGGLE_CONTROL_ID-->",
L"<--A description of your preview handler-->",
L"xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx", // your preview handler CLSID.
L"<--A display name for your preview handler-->")
```
## Installation
### MSI
To add a new Previewer update the `Product.wxs` file in `PowerToysSetup` similar to existing Previewer to register the Preview Handler. More details about registration of Preview Handlers can be [found here.](https://docs.microsoft.com/en-us/windows/win32/shell/how-to-register-a-preview-handler)
```xml
```
## Managing Preview Handlers
After successful integration, your preview handler should appear in the PowerToys settings UI under the `File Explorer Preview` Tab. In here you should be able to enable and disable your preview handler.
In the general settings of the Settings UI, you should be able to disable and enable all the preview handlers all at once.
