Walkthrough: Customizing the Text View

Article
01/27/2013

You can customize a text view by modifying any of the following properties in its editor-format map:

Indicator margin
Insertion caret
Overwrite caret
Selected text
Inactive selected text (that is, selected text that has lost focus)
Visible whitespace

Prerequisites

To complete this walkthrough, you must install the Visual Studio 2012 SDK. For more information about the Visual Studio SDK and to download it, see Visual Studio Extensibility Developer Center on the MSDN Web site.

Creating a Managed Extensibility Framework (MEF) Project

To create a MEF project

Create a C# Editor Classifier project or Visual Basic Editor Classifier project. Name the solution ViewPropertyTest.
Open the source.extension.vsixmanifest file in the VSIX Manifest Editor.
Make sure that the Content block contains a MEF Component content type set to the current project.
```
<Content>
    <MefComponent>|%CurrentProject%|</MefComponent>
  </Content>
```
Save and close source.extension.vsixmanifest.
Delete the existing class files.

Defining the Content Type

To define a content type

Add a class file and name it ViewPropertyModifier.

Add the following using directives (Imports statements in Visual Basic).

Imports System
Imports System.Collections
Imports System.Windows
Imports System.Windows.Media
Imports System.ComponentModel.Composition
Imports Microsoft.VisualStudio.Text.Classification
Imports Microsoft.VisualStudio.Text.Editor
Imports Microsoft.VisualStudio.Utilities

using System;
using System.Collections;
using System.Windows;
using System.Windows.Media;
using System.ComponentModel.Composition;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Utilities;

Declare a class named TestViewCreationListener that inherits from IWpfTextViewCreationListener. Export this class with the following attributes:

ContentTypeAttribute to specify the type of content to which this listener applies.
TextViewRoleAttribute to specify the role of this listener.

<Export(GetType(IWpfTextViewCreationListener)), ContentType("text"), TextViewRole(PredefinedTextViewRoles.Document)>
Friend Class TestViewCreationListener
    Implements IWpfTextViewCreationListener

[Export(typeof(IWpfTextViewCreationListener))]
[ContentType("text")]
[TextViewRole(PredefinedTextViewRoles.Document)]
internal class TestViewCreationListener : IWpfTextViewCreationListener

In this class, import the IEditorFormatMapService.

<Import()>
Friend FormatMapService As IEditorFormatMapService = Nothing

[Import]
internal IEditorFormatMapService FormatMapService = null;

Changing the View Properties

To change the view properties

Implement the TextViewCreated method so that the view properties are changed when the view is opened. To make the change, first find the ResourceDictionary that corresponds to the aspect of the view you want to find. Then change the appropriate property in the resource dictionary and set the properties. Batch the calls to the SetProperties method by calling the BeginBatchUpdate method before you set the properties and then the EndBatchUpdate after you set the properties.

Public Sub TextViewCreated(ByVal textView As IWpfTextView) Implements IWpfTextViewCreationListener.TextViewCreated

    Dim formatMap As IEditorFormatMap = FormatMapService.GetEditorFormatMap(textView)

    Dim regularCaretProperties As ResourceDictionary = formatMap.GetProperties("Caret")
    Dim overwriteCaretProperties As ResourceDictionary = formatMap.GetProperties("Overwrite Caret")
    Dim indicatorMargin As ResourceDictionary = formatMap.GetProperties("Indicator Margin")
    Dim visibleWhitespace As ResourceDictionary = formatMap.GetProperties("Visible Whitespace")
    Dim selectedText As ResourceDictionary = formatMap.GetProperties("Selected Text")
    Dim inactiveSelectedText As ResourceDictionary = formatMap.GetProperties("Inactive Selected Text")

    formatMap.BeginBatchUpdate()

    regularCaretProperties(EditorFormatDefinition.ForegroundBrushId) = Brushes.Magenta
    formatMap.SetProperties("Caret", regularCaretProperties)

    overwriteCaretProperties(EditorFormatDefinition.ForegroundBrushId) = Brushes.Turquoise
    formatMap.SetProperties("Overwrite Caret", overwriteCaretProperties)

    indicatorMargin(EditorFormatDefinition.BackgroundColorId) = Colors.LightGreen
    formatMap.SetProperties("Indicator Margin", indicatorMargin)

    visibleWhitespace(EditorFormatDefinition.ForegroundColorId) = Colors.Red
    formatMap.SetProperties("Visible Whitespace", visibleWhitespace)

    selectedText(EditorFormatDefinition.BackgroundBrushId) = Brushes.LightPink
    formatMap.SetProperties("Selected Text", selectedText)

    inactiveSelectedText(EditorFormatDefinition.BackgroundBrushId) = Brushes.DeepPink
    formatMap.SetProperties("Inactive Selected Text", inactiveSelectedText)

    formatMap.EndBatchUpdate()
End Sub

public void TextViewCreated(IWpfTextView textView)
{
    IEditorFormatMap formatMap = FormatMapService.GetEditorFormatMap(textView);

    ResourceDictionary regularCaretProperties = formatMap.GetProperties("Caret");
    ResourceDictionary overwriteCaretProperties = formatMap.GetProperties("Overwrite Caret");
    ResourceDictionary indicatorMargin = formatMap.GetProperties("Indicator Margin");
    ResourceDictionary visibleWhitespace = formatMap.GetProperties("Visible Whitespace");
    ResourceDictionary selectedText = formatMap.GetProperties("Selected Text");
    ResourceDictionary inactiveSelectedText = formatMap.GetProperties("Inactive Selected Text");

    formatMap.BeginBatchUpdate();

    regularCaretProperties[EditorFormatDefinition.ForegroundBrushId] = Brushes.Magenta;
    formatMap.SetProperties("Caret", regularCaretProperties);

    overwriteCaretProperties[EditorFormatDefinition.ForegroundBrushId] = Brushes.Turquoise;
    formatMap.SetProperties("Overwrite Caret", overwriteCaretProperties);

    indicatorMargin[EditorFormatDefinition.BackgroundColorId] = Colors.LightGreen;
    formatMap.SetProperties("Indicator Margin", indicatorMargin);

    visibleWhitespace[EditorFormatDefinition.ForegroundColorId] = Colors.Red;
    formatMap.SetProperties("Visible Whitespace", visibleWhitespace);

    selectedText[EditorFormatDefinition.BackgroundBrushId] = Brushes.LightPink;
    formatMap.SetProperties("Selected Text", selectedText);

    inactiveSelectedText[EditorFormatDefinition.BackgroundBrushId] = Brushes.DeepPink;
    formatMap.SetProperties("Inactive Selected Text", inactiveSelectedText);

    formatMap.EndBatchUpdate();
}

Building and Testing the Code

To build and test the code

Build the solution.

When you run this project in the debugger, a second instance of Visual Studio is instantiated.
Create a text file and type some text.
- The insertion caret should be magenta and the overwrite caret should be turquoise.
- The indicator margin (to the left of the text view) should be light green.
Select the text you just typed. The color of the selected text should be light pink.
While the text is selected, click anywhere outside the text window. The color of the selected text should be dark pink.
Turn on visible whitespace. (On the Edit menu, point to Advanced and then click View White Space). Type some tabs in the text. Red arrows that represent the tabs should be displayed.

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