# Spellcheck The **RadRichTextEditor** control is designed to support "*spell checking as you type*" by setting a single property and specifying a proper dictionary to it. This topic will explain you the following: * [Enabling SpellCheck](https://www.telerik.com/products/winforms/documentation/controls/richtexteditor/features/spellcheck#enabling-spellcheck) * [Dictionaries](https://www.telerik.com/products/winforms/documentation/controls/richtexteditor/features/spellcheck#dictionaries) * [Custom Dictionaries](https://www.telerik.com/products/winforms/documentation/controls/richtexteditor/features/spellcheck#custom-dictionaries) * [Adding a Word](https://www.telerik.com/products/winforms/documentation/controls/richtexteditor/features/spellcheck#adding-a-word) * [Internationalization](https://www.telerik.com/products/winforms/documentation/controls/richtexteditor/features/spellcheck#internationalization) ## Enabling SpellCheck To enable or disable the spell checking functionality (present as red wavy underlines below unrecognized words), you can use the **IsSpellCheckingEnabled** property on **RadRichTextEditor**. When the property is *false*, no dictionaries are loaded and no overhead is incurred for spell checking. > caption Figure 1: Spell Checking as you type ![WinForms RadRichTextEditor Spell checking as you type](https://www.telerik.com/products/winforms/documentation/assets/51cfc4ad9939dffb6edb443a91fec2ef/richtexteditor-features-spellcheck001.png) You can customize the spell checker by using the **SpellChecker** property of **RadRichTextEditor**. It’s of type **ISpellChecker**. By default, an object of type **DocumentSpellChecker** that implements the interface, is used for this property. You can either use it or provide your custom class that implements the **ISpellChecker** interface. When you right click a misspelled word, the context menu gives you the opportunity to open a **SpellCheckingDialog**. Thus, the user can correct the word, add it to the dictionary or ignore it. > note Since R2 2017 SP the SpellCheckingDialog allows the user to enter some custom text by using a RadTextBox if no appropriate word exist in the offered list. > caption Figure 2: Spell checking dialog ![WinForms RadRichTextEditor Spell checking dialog](https://www.telerik.com/products/winforms/documentation/assets/c1deb913519fbf9ffa272e83bbf5d68c/richtexteditor-features-spellcheck002.png) > note **RadRichTextEditor** can also be configured to be used with a spell-checker using an OpenOffice dictionary and the NHunspell library: [RadRichTextEditor OpenOffice Spell Checking](http://www.telerik.com/support/code-library/radrichtexteditor-openoffice-spell-checking). ## Dictionaries The dictionaries in **RadRichTextEditor** implement the **IWordDictionary** interface. Easy interoperability with dictionaries from **RadSpell** for ASP.NET is achieved through the **RadDictionary** class, which supports the loading of a dictionary directly from the \*.tdf files, used with **RadSpell**. You can find TDF dictionaries for some languages [here](http://www.telerik.com/support/code-library/dictionaries-for-radspellchecker). Here is an example of a **RadDictionary** loaded from a TDF file. > note When adding a **RadDictionary** or similar object use the **AddDictionary(IWordDictionary dictionary, CultureInfo culture)** method of the **DocumentSpellChecker** . You can also associate a dictionary with a specific culture. The method to remove this dictionary is **RemoveDictionary(CultureInfo culture)** . > note The given example doesn't contain the logic used to read the **TDF** file as a **Stream** . ```C# private void LoadDictionary1(Stream tdfFileStream) { RadDictionary dictionary = new RadDictionary(); dictionary.Load(tdfFileStream); ((DocumentSpellChecker)this.radRichTextEditor1.SpellChecker).AddDictionary(dictionary, new CultureInfo("de-DE")); } ``` ```VB.NET Private Sub LoadDictionary1(ByVal tdfFileStream As Stream) Dim dictionary As New RadDictionary() dictionary.Load(tdfFileStream) CType(Me.radRichTextEditor1.SpellChecker, DocumentSpellChecker).AddDictionary(dictionary, New CultureInfo("de-DE")) End Sub ``` ## RadWordsDictionary **RadWordsDictionary** implements the **IWordDictionary** interface and is capable of reading words from text files that contain one word per line. An example of such files are the **.dic** dictionaries. #### Load stream in RadWordsDictionary ```C# private void LoadWordDictionaryStream(Stream dictStrem) { Telerik.WinControls.SpellChecker.Proofing.RadWordsDictionary dictionary = new Telerik.WinControls.SpellChecker.Proofing.RadWordsDictionary(); dictionary.Load(dictStrem); } ``` ```VB.NET Private Sub LoadWordDictionaryStream(dictStrem As Stream) Dim dictionary As New Telerik.WinControls.SpellChecker.Proofing.RadWordsDictionary() dictionary.Load(dictStrem) End Sub ``` One of the constructor overloads of the **RadWordsDictionary** class enables you to pass a parameter of type **IEnumerable\**, which can help you create your own dictionary with a custom set of words. #### Create RadWordsDictionary from strings ```C# private void LoadWordDictionaryStream() { List words = new List(); words.Add("Test"); words.Add("Teacher"); words.Add("Sister"); Telerik.WinControls.SpellChecker.Proofing.RadWordsDictionary dictionary = new Telerik.WinControls.SpellChecker.Proofing.RadWordsDictionary(); dictionary.Load(words); } ``` ```VB.NET Private Sub LoadWordDictionaryStream() Dim words As New List(Of String)() words.Add("Test") words.Add("Teacher") words.Add("Sister") Dim dictionary As New Telerik.WinControls.SpellChecker.Proofing.RadWordsDictionary() dictionary.Load(words) End Sub ``` ## Custom Dictionaries One feature of the **SpellChecker** in **RadRichTextEditor** is to add a word to a user-defined custom dictionary to enable domain-specific applications. Such dictionary should implement the **IWordCustomDictionary** interface. For that purpose the **RadRichTextEditor** provides you with the **RadIsolatedStorageCustomDictionary** class out of the box. It allows you to persist the word list in a file located in the Isolated Storage. Here is an example of a such dictionary which adds the words in the "CustomDictionary.txt" marked as a Site-scoped **IsolatedSotrageFile**. > tip The **IsolatedStorageScope** enumeration has the following values: > > * **Site** - the dictionary defined in this scope is available for each application hosted on the same site. > * **Application** - the dictionary is available only for the particular application.> > note When adding a dictionary that implements the **ICustomWordDictionary** interface object use **AddCustomDictionary(ICustomWordDictionary customDictionary, CultureInfo culture)** method for the **DocumentSpellChecker** class. You can also associate a custom dictionary to a specific culture. The method to remove it is **RemoveCustomDictionary(ICustomWordDictionary customDictionary, CultureInfo culture)** . ```C# private void CreateCustomDictionary() { RadIsolatedStorageCustomDictionary dictionary = new RadIsolatedStorageCustomDictionary(IsolatedStorageScope.Site, "CustomDictionary.txt"); DocumentSpellChecker spellchecker = new DocumentSpellChecker(dictionary); this.radRichTextEditor1.SpellChecker = spellchecker; } ``` ```VB.NET Private Sub CreateCustomDictionary() Dim dictionary As New RadIsolatedStorageCustomDictionary(IsolatedStorageScope.Site, "CustomDictionary.txt") Dim spellchecker As New DocumentSpellChecker(dictionary) Me.radRichTextEditor1.SpellChecker = spellchecker End Sub ``` If you want to have a temporary custom dictionary, that will only be available for a single application session, you can use the **RadNonPersistentCustomDictionary** object. ## Adding a Word To add a word to a dictionary you can either use the **AddWord** method of the **DocumentSpellChecker** or of the dictionary itself. Using the first one you can add a word to multiple dictionaries associated to the same culture. This is done by passing the desired culture as parameter to the method. > note Using the overload of the **AddWord** method that takes only the word as argument is equal to using the second overload and passing **CultureInfo.InvariantCulture** as argument. Using the **AddWord** method of the dictionary itself will add the word only to the respective dictionary. Here is an example. ```C# this.radRichTextEditor1.SpellChecker.AddWord("RadRichTextEditor", CultureInfo.InvariantCulture); ``` ```VB.NET Me.radRichTextEditor1.SpellChecker.AddWord("RadRichTextEditor", CultureInfo.InvariantCulture) ``` ## Internationalization The spell checking component is designed to suit scenarios where different cultures take place in the same application. Internationalization is achieved through associating each dictionary and custom dictionary with a specific culture (or the **InvariantCulture** as the default one). Here is an example. > note The given example doesn't contain the logic used to read the **TDF** file as a **Stream** . ```C# private void LoadDictionary1(Stream tdfFileStream) { RadDictionary dictionary = new RadDictionary(); dictionary.Load(tdfFileStream); ((DocumentSpellChecker)this.radRichTextEditor1.SpellChecker).AddDictionary(dictionary, new CultureInfo("de-DE")); } ``` ```VB.NET Private Sub LoadDictionary1(ByVal tdfFileStream As Stream) Dim dictionary As New RadDictionary() dictionary.Load(tdfFileStream) CType(Me.radRichTextEditor1.SpellChecker, DocumentSpellChecker).AddDictionary(dictionary, New CultureInfo("de-DE")) End Sub ``` ## See Also * [How to Extract the Words Added to the Dictionary in RadSpellChecker](https://www.telerik.com/products/winforms/documentation/knowledge-base/extract-words-added-to-dictionary) * [How to Share Localization Providers and Spell Checking Dictionaries](https://www.telerik.com/products/winforms/documentation/knowledge-base/share-localization-providers-and-dictionaries)