Walkthrough: Creating a Core Editor and Registering an Editor File Type

Article
11/15/2016

Note

This article applies to Visual Studio 2015. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

This walkthrough demonstrates how to create a VSPackage that starts the Visual Studio core editor when a file that has the .myext file name extension is loaded.

Prerequisites

To follow this walkthrough, you must install the Visual Studio SDK. For more information, see Visual Studio SDK.

Locations for the Visual Studio Package Project template

The Visual Studio Package project template can be found in three different locations in the New Project dialog:

Under Visual Basic Extensibility. The default language of the project is Visual Basic.
Under C# Extensibility. The default language of the project is C#.
Under Other Project Types Extensibility. The default language of the project is C++.

To create the VSPackage

Start Visual Studio and create a Visual C# VSPackage named MyPackage, as outlined in Walkthrough: Creating a Menu Command VSPackage.

To add the editor factory

Right-click the MyPackage project, point to Add and then click Class.
In the Add New Item dialog box, make sure the Class template is selected, type EditorFactory.cs for the name, and then click Add to add the class to your project.

The EditorFactory.cs file should be automatically opened.

Reference the following assemblies from your code.

Imports System.Runtime.InteropServices  
Imports Microsoft.VisualStudio  
Imports Microsoft.VisualStudio.Shell  
Imports Microsoft.VisualStudio.Shell.Interop  
Imports Microsoft.VisualStudio.OLE.Interop  
Imports Microsoft.VisualStudio.TextManager.Interop  
Imports IOleServiceProvider = Microsoft.VisualStudio.OLE.Interop.IServiceProvider

using System.Runtime.InteropServices;  
using Microsoft.VisualStudio;  
using Microsoft.VisualStudio.Shell;  
using Microsoft.VisualStudio.Shell.Interop;  
using Microsoft.VisualStudio.OLE.Interop;  
using Microsoft.VisualStudio.TextManager.Interop;  
using IOleServiceProvider = Microsoft.VisualStudio.OLE.Interop.IServiceProvider;

Add a GUID to the EditorFactory class by adding the Guid attribute immediately before the class declaration.

You can generate a new GUID by using the guidgen.exe program at the Visual Studio command prompt, or by clicking Create GUID on the Tools menu. The GUID used here is only an example; do not use it in your project.
```
<Guid("0eea3187-c5fa-48d4-aa72-b5eecd3b17b1")> _  
```
```
[Guid("0eea3187-c5fa-48d4-aa72-b5eecd3b17b1")]   
```

In the class definition, add two private variables to contain the parent package and a service provider.

Class EditorFactory  
    Private parentPackage As Package  
    Private serviceProvider As IOleServiceProvider

class EditorFactory  
{  
    private Package parentPackage;  
    private IOleServiceProvider serviceProvider;  
}

Add a public class constructor that takes one parameter of type Package:

Public Sub New(ByVal parentPackage As Package)  
    Me.parentPackage = parentPackage  
End Sub

public EditorFactory(Package parentPackage)  
{  
    this.parentPackage = parentPackage;  
}

Modify the EditorFactory class declaration to derive from the IVsEditorFactory interface.

Class EditorFactory Implements IVsEditorFacto

class EditorFactory : IVsEditorFactory

Right-click IVsEditorFactory, click Implement Interface, and then click Implement Interface Explicitly.

This adds the four methods that must be implemented in the IVsEditorFactory interface.
Replace the contents of the IVsEditorFactory.Close method with the following code.
```
Return VSConstants.S_OK  
```
```
return VSConstants.S_OK;  
```

Replace the contents of the IVsEditorFactory.SetSite with the following code.

Me.serviceProvider = psp  
Return VSConstants.S_OK

this.serviceProvider = psp;  
return VSConstants.S_OK;

Replace the contents of the IVsEditorFactory.MapLogicalView method with the following code.

Dim retval As Integer = VSConstants.E_NOTIMPL  
pbstrPhysicalView = Nothing ' We support only one view.  
If rguidLogicalView.Equals(VSConstants.LOGVIEWID_Designer)OrElse _  
rguidLogicalView.Equals(VSConstants.LOGVIEWID_Primary) Then  
    retval = VSConstants.S_OK  
End If  
Return retval

int retval = VSConstants.E_NOTIMPL;  
pbstrPhysicalView = null;   // We support only one view.  
if (rguidLogicalView.Equals(VSConstants.LOGVIEWID_Designer) ||  
rguidLogicalView.Equals(VSConstants.LOGVIEWID_Primary))  
{  
    retval = VSConstants.S_OK;  
}  
return retval;

Replace the contents of the IVsEditorFactory.CreateEditorInstance method with the following code.

Dim retval As Integer = VSConstants.E_FAIL          

' Initialize these to empty to start with   
ppunkDocView = IntPtr.Zero  
ppunkDocData = IntPtr.Zero  
pbstrEditorCaption = ""  
pguidCmdUI = Guid.Empty  
pgrfCDW = 0  

If (grfCreateDoc And (VSConstants.CEF_OPENFILE Or _  
VSConstants.CEF_SILENT)) = 0 Then  
    Throw New ArgumentException("Only Open or Silent is valid")  
End If  
If punkDocDataExisting <> IntPtr.Zero Then  
    Return VSConstants.VS_E_INCOMPATIBLEDOCDATA  
End If  

' Instantiate a text buffer of type VsTextBuffer.   
' Note: we only need an IUnknown (object) interface for   
' this invocation.   
Dim clsidTextBuffer As Guid = GetType(VsTextBufferClass).GUID  
Dim iidTextBuffer As Guid = VSConstants.IID_IUnknown  
Dim pTextBuffer As Object = pTextBuffer = _  
parentPackage.CreateInstance(clsidTextBuffer, iidTextBuffer, _  
GetType(Object))  

If Not pTextBuffer Is Nothing Then  
    ' "Site" the text buffer with the service provider we were   
    ' provided.   
    Dim textBufferSite As IObjectWithSite = TryCast(pTextBuffer, _  
    IObjectWithSite)  
    If Not textBufferSite Is Nothing Then  
        textBufferSite.SetSite(Me.serviceProvider)  
    End If  

    ' Instantiate a code window of type IVsCodeWindow.   
    Dim clsidCodeWindow As Guid = GetType(VsCodeWindowClass).GUID  
    Dim iidCodeWindow As Guid = GetType(IVsCodeWindow).GUID  
    Dim pCodeWindow As IVsCodeWindow = _  
    CType(Me.parentPackage.CreateInstance(clsidCodeWindow, _  
    iidCodeWindow, GetType(IVsCodeWindow)), IVsCodeWindow)  
    If Not pCodeWindow Is Nothing Then  
        ' Give the text buffer to the code window.   
        ' We are giving up ownership of the text buffer!   
        pCodeWindow.SetBuffer(CType(pTextBuffer, IVsTextLines))  

        ' Now tell the caller about all this new stuff   
        ' that has been created.   
        ppunkDocView = Marshal.GetIUnknownForObject(pCodeWindow)  
        ppunkDocData = Marshal.GetIUnknownForObject(pTextBuffer)  

        ' Specify the command UI to use so keypresses are   
        ' automatically dealt with.   
        pguidCmdUI = VSConstants.GUID_TextEditorFactory  

        ' This caption is appended to the filename and   
        ' lets us know our invocation of the core editor   
        ' is up and running.   
        pbstrEditorCaption = " [MyPackage]"  

        retval = VSConstants.S_OK  
    End If  
End If  
Return retval

int retval = VSConstants.E_FAIL;  

// Initialize these to empty to start with  
ppunkDocView       = IntPtr.Zero;  
ppunkDocData       = IntPtr.Zero;  
pbstrEditorCaption = "";  
pguidCmdUI         = Guid.Empty;   
pgrfCDW            = 0;  

if ((grfCreateDoc & (VSConstants.CEF_OPENFILE |   
      VSConstants.CEF_SILENT)) == 0)  
{   
    throw new ArgumentException("Only Open or Silent is valid");  
}  
if (punkDocDataExisting != IntPtr.Zero)  
{  
    return VSConstants.VS_E_INCOMPATIBLEDOCDATA;  
}  

// Instantiate a text buffer of type VsTextBuffer.  
// Note: we only need an IUnknown (object) interface for   
// this invocation.  
Guid clsidTextBuffer = typeof(VsTextBufferClass).GUID;  
Guid iidTextBuffer   = VSConstants.IID_IUnknown;  
object pTextBuffer   = pTextBuffer = parentPackage.CreateInstance(  
      ref clsidTextBuffer,  
      ref iidTextBuffer,  
      typeof(object));  

if (pTextBuffer != null)  
{  
    // "Site" the text buffer with the service provider we were  
    // provided.  
    IObjectWithSite textBufferSite = pTextBuffer as IObjectWithSite;  
    if (textBufferSite != null)  
    {  
        textBufferSite.SetSite(this.serviceProvider);  
    }  

    // Instantiate a code window of type IVsCodeWindow.  
    Guid clsidCodeWindow = typeof(VsCodeWindowClass).GUID;  
    Guid iidCodeWindow   = typeof(IVsCodeWindow).GUID;  
    IVsCodeWindow pCodeWindow =  
    (IVsCodeWindow)this.parentPackage.CreateInstance(   
          ref clsidCodeWindow,  
          ref iidCodeWindow,  
          typeof(IVsCodeWindow));  
    if (pCodeWindow != null)  
    {  
        // Give the text buffer to the code window.  
        // We are giving up ownership of the text buffer!  
        pCodeWindow.SetBuffer((IVsTextLines)pTextBuffer);  

        // Now tell the caller about all this new stuff   
        // that has been created.  
        ppunkDocView = Marshal.GetIUnknownForObject(pCodeWindow);  
        ppunkDocData = Marshal.GetIUnknownForObject(pTextBuffer);  

        // Specify the command UI to use so keypresses are   
        // automatically dealt with.  
        pguidCmdUI = VSConstants.GUID_TextEditorFactory;  

        // This caption is appended to the filename and  
        // lets us know our invocation of the core editor   
        // is up and running.  
        pbstrEditorCaption = " [MyPackage]";  

        retval = VSConstants.S_OK;  
    }   
}   
return retval;

Compile the project and make sure there are no errors.

To register the editor factory

In Solution Explorer, double-click the Resources.resx file to open it to the string table, in which the entry String1 is selected.
Change the name of the identifier to IDS_EDITORNAME and the text to MyPackage Editor. This string will appear as the name of your editor.
Open the VSPackage.resx file and add a new string, set the name to 101 and the value to IDS_EDITORNAME. This provides the package with a resource ID to access the string you just created.

Note

If the VSPackage.resx file contains another string that the name attribute set to 101, substitute another unique, numeric value, here and in the following steps.
In Solution Explorer, open the MyPackagePackage.cs file.

This is the main package file.

Add the following user attributes just before the Guid attribute.

<ProvideEditorFactoryAttribute(GetType(EditorFactory), 101)> _  
<ProvideEditorExtensionAttribute(GetType(EditorFactory), _  
      ".myext", 32, NameResourceID:=101 )> _

[ProvideEditorFactory(typeof(EditorFactory), 101)]  
[ProvideEditorExtension(typeof(EditorFactory),   
      ".myext", 32, NameResourceID = 101)]

The ProvideEditorExtensionAttribute attribute associates the .myext file extension with your editor factory so that any time a file that has that extension is loaded, your editor factory is invoked.

Add a private variable to the MyPackage class, just before the constructor, and give it the type EditorFactory.
```
Private editorFactory As EditorFactory  
```
```
private EditorFactory editorFactory;  
```

Find the Initialize method (you may have to open the Package Members hidden region) and add the following code after the call to base.Initialize().

'Create our editor factory and register it.   
Me.editorFactory = New EditorFactory(Me)  
MyBase.RegisterEditorFactory(Me.editorFactory)

// Create our editor factory and register it.  
this.editorFactory = new EditorFactory(this);  
base.RegisterEditorFactory(this.editorFactory);

Compile the program and make sure there are no errors.

This step registers the editor factory in the experimental registry hive for Visual Studio. If you are prompted to override the resource.h file, click OK.
Create a sample file named TextFile1.myext.
Press F5 to open an instance of the experimental Visual Studio.
In the experimental Visual Studio, on the File menu, point to Open and then click File.
Find TextFile1.myext and then click Open.

The file should now be loaded.

Robust Programming

The Visual Studio core editor handles a wide range of text-based file types and works closely with language services to provide a rich set of features such as syntax highlighting, brace matching, and IntelliSense word-completion and member-completion lists. If you are working with text-based files, then you can use the core editor together with a custom language service that supports your specific file types.

A VSPackage can invoke the Visual Studio core editor by supplying an editor factory. This editor factory is used any time a file that is associated with it is loaded. If the file is part of a project, then the core editor is automatically invoked unless overridden by your VSPackage. However, if the file is loaded outside of a project, then the core editor must be explicitly invoked by your VSPackage.

For more information about the core editor, see Inside the Core Editor.