windowsforms-9890-controls-and-libraries-rich-text-editor-autocorrect.md
The RichEditControl AutoCorrect feature can help you automate inserting frequently used text, auto-correcting typing errors and misspelled capitalization. You can specify the built-in options construct a custom replacement table or handle the Autocorrect event to analyze the input text and provide the necessary substitution.
The following members enable you to enable certain automatic correction features:
| Property | Description |
|---|---|
| AutoCorrectOptions.DetectUrls | Automatically detects an inserted web address, a network path or email address and converts it to a hyperlink. |
| AutoCorrectOptions.CorrectTwoInitialCapitals | Corrects capitalization errors. |
| AutoCorrectOptions.ReplaceTextAsYouType | Scans for entries as you type and replaces them with the designated text or image. |
| AutoCorrectOptions.UseSpellCheckerSuggestions | Automatically detects and corrects typos and misspelled word if the RichEditControl.SpellChecker property specifies a spell checker component. If the spell checker provides one suggestion, this suggestion automatically substitutes the incorrect word. Otherwise, no changes are made. |
Use the richEditControl.Options.AutoCorrect notation to access the built-in autocorrect options, as shown in the code snippet below:
AutoCorrectOptions correctionOptions = richEditControl1.Options.AutoCorrect;
correctionOptions.CorrectTwoInitialCapitals = true;
correctionOptions.DetectUrls = false;
correctionOptions.ReplaceTextAsYouType = true;
correctionOptions.UseSpellCheckerSuggestions = true;
Dim correctionOptions As AutoCorrectOptions = richEditControl1.Options.AutoCorrect
correctionOptions.CorrectTwoInitialCapitals = True
correctionOptions.DetectUrls = False
correctionOptions.ReplaceTextAsYouType = True
correctionOptions.UseSpellCheckerSuggestions = True
The text expander functionality allows you to insert symbols, decipher abbreviations and insert images. Follow the steps below to implement the text expander:
Create a new AutoCorrectReplaceInfoCollection instance and fill it with AutoCorrectReplaceInfo entries:
private AutoCorrectReplaceInfoCollection LoadAbbrevs(string path)
{
AutoCorrectReplaceInfoCollection coll = new AutoCorrectReplaceInfoCollection();
string aLine = "";
AutoCorrectReplaceInfo acrInfoIm = new AutoCorrectReplaceInfo(":-)", CreateImageFromResx("smile.png"));
coll.Add(acrInfoIm);
if (File.Exists(path))
{
StreamReader sr = new StreamReader(path);
while (!(sr.EndOfStream))
{
aLine = sr.ReadLine();
if (aLine != "START") continue;
while (!(sr.EndOfStream))
{
aLine = sr.ReadLine();
aLine = aLine.Trim();
string[] words = aLine.Split('=');
if (words.Length == 2)
{
AutoCorrectReplaceInfo acrInfo = new AutoCorrectReplaceInfo(words[0], words[1]);
coll.Add(acrInfo);
}
}
}
sr.Close();
}
return coll;
}
Private Function LoadAbbrevs(ByVal path As String) As AutoCorrectReplaceInfoCollection
Dim coll As New AutoCorrectReplaceInfoCollection()
Dim aLine As String = ""
Dim acrInfoIm As New AutoCorrectReplaceInfo(":-)", CreateImageFromResx("smile.png"))
coll.Add(acrInfoIm)
If File.Exists(path) Then
Dim sr As New StreamReader(path)
Do While Not(sr.EndOfStream)
aLine = sr.ReadLine()
If aLine <> "START" Then
Continue Do
End If
Do While Not(sr.EndOfStream)
aLine = sr.ReadLine()
aLine = aLine.Trim()
Dim words() As String = aLine.Split("="c)
If words.Length = 2 Then
Dim acrInfo As New AutoCorrectReplaceInfo(words(0), words(1))
coll.Add(acrInfo)
End If
Loop
Loop
sr.Close()
End If
Return coll
End Function
Call the IAutoCorrectService.SetReplaceTable method to register a created replacement list. Register the service after the RichEditControl instance is completely loaded, i.e. in the Form.Loaded event handler.
IAutoCorrectService svc = richEditControl1.GetService<IAutoCorrectService>();
if (svc != null)
svc.SetReplaceTable(LoadAbbrevs("abbvs.txt"));
Dim svc As IAutoCorrectService = richEditControl1.GetService(Of IAutoCorrectService)()
If svc IsNot Nothing Then
svc.SetReplaceTable(LoadAbbrevs("abbvs.txt"))
End If
When you type a space, punctuation mark or carriage return (a character that typically means you have finished typing a word), AutoCorrect compares the word (or more precisely the group of characters) against its list of entries. If the word matches an entry, AutoCorrect substitutes this word with a replacement object.
In this example, the substitution is performed as shown in the animation below:
Handle the RichEditControl.AutoCorrect event to analyze the input text and provide a specific object for replacement. Use the following API (accessible using the AutoCorrectEventArgs.AutoCorrectInfo property) to perform the desired actions:
| API | Description |
|---|---|
| AutoCorrectInfo.Text | Gets the input string to check whether it should be replaced. |
| AutoCorrectInfo.IncrementStartPosition | Decreases a text range being analyzed by moving its start by one position. |
| AutoCorrectInfo.DecrementStartPosition | Extends a text range being analyzed by moving its start by one position. |
| AutoCorrectInfo.IncrementEndPosition | Extends a text range being analyzed by moving its end by one position. |
| AutoCorrectInfo.DecrementEndPosition | Decreases a text range being analyzed by moving its end by one position. |
| AutoCorrectInfo.ReplaceWith | Gets or sets the object used to replace the input string in the document. |
The following code sample shows how to handle the RichEditControl.AutoCorrect event to replace the typed $ symbol with a picture of a dollar, and substitute the text enclosed in percent symbols with custom content.
private void richEditControl1_AutoCorrect(object sender, DevExpress.XtraRichEdit.AutoCorrectEventArgs e)
{
AutoCorrectInfo info = e.AutoCorrectInfo;
e.AutoCorrectInfo = null;
if (info.Text.Length <= 0)
return;
//Find a dollar and the percent sign in the obtained text
for (; ; )
{
if (!info.DecrementStartPosition())
return;
if (IsSeparator(info.Text[0]))
return;
if (info.Text[0] == '$')
{
//Replace the dollar sign with an image
info.ReplaceWith = CreateImageFromResx("dollar_pic.png");
e.AutoCorrectInfo = info;
return;
}
if (info.Text[0] == '%')
{
//Replace a text between dollar signs with a custom content
string replaceString = CalculateFunction(info.Text);
if (!String.IsNullOrEmpty(replaceString))
{
info.ReplaceWith = replaceString;
e.AutoCorrectInfo = info;
}
return;
}
}
}
Private Sub richEditControl1_AutoCorrect(ByVal sender As Object, ByVal e As DevExpress.XtraRichEdit.AutoCorrectEventArgs) Handles richEditControl1.AutoCorrect
Dim info As AutoCorrectInfo = e.AutoCorrectInfo
e.AutoCorrectInfo = Nothing
If info.Text.Length <= 0 Then
Return
End If
' Find a dollar and the percent sign in the obtained text
Do
If Not info.DecrementStartPosition() Then
Return
End If
If IsSeparator(info.Text(0)) Then
Return
End If
'Replace the dollar sign with an image
If info.Text(0) = "$"c Then
info.ReplaceWith = CreateImageFromResx("dollar_pic.png")
e.AutoCorrectInfo = info
Return
End If
'Replace a text between dollar signs with a custom content
If info.Text(0) = "%"c Then
Dim replaceString As String = CalculateFunction(info.Text)
If Not String.IsNullOrEmpty(replaceString) Then
info.ReplaceWith = replaceString
e.AutoCorrectInfo = info
End If
Return
End If
Loop
End Sub