如何根据C＃中的字符串更改RichTextBox文本

Question

So, I am trying to build a RichTextBox which allows me to write code into it and changes the color of the keywords based on C# programming language.

First of all, I've declared this:

string[] palavraschave = { "abstract", "as", "base", "bool", "break", "byte", "case", "catch", "char", "checked", "class", "const", "continue", "decimal", "default", 
     "delegate", "do", "double", "else", "enum", "event", "explicit", "extern", "false", "finally", "fixed", "float", "for", "foreach", "goto",
     "if", "implicit", "in", "int", "interface", "internal", "is", "lock", "long", "namespace", "new", "null", "object", "operator", "out", 
     "override", "params", "private", "protected", "public", "readonly", "ref", "return", "sbyte", "sealed", "short", "sizeof", "stackalloc", 
     "static", "string", "struct", "switch", "this", "throw", "true", "try", "typeof", "uint", "ulong", "unchecked", "unsafe", "ushort", 
     "using", "virtual", "void", "volatile", "while", "add", "alias", "ascending", "descending", "dynamic", "from", "get", "global", "group", 
     "into", "join", "let", "orderby", "partial", "remove", "select", "set", "value", "var", "where", "yield" };

Then I have a method to check the RichTextBox :

private void CheckRichTextBox(string word, Color color, int startIndex)
{
    if (this.rchBoxText.Text.Contains(word))
    {
        int index = -1;
        int selectStart = this.rchBoxText.SelectionStart;

        while ((index = this.rchBoxText.Text.IndexOf(word, (index + 1))) != -1)
        {
            this.rchBoxText.Select((index + startIndex), word.Length);
            this.rchBoxText.SelectionColor = cor;
            this.rchBoxText.Select(selectStart, 0);
            this.rchBoxText.SelectionColor = Color.Black;
        }
    }
}

To call it, I will use this piece of code into the RichTextBox TextChanged event:

this.CheckRichTextBox(palavraschave.ToString(), Color.Blue, 0);

But it does not work. What am I doing wrong?

Answer 1

You would need to do a for each on the array of words and call your procedure for each word rather calling toString. Or pass the array to your function and loop in there.

But as other people have said there are plenty of solutions for this type of thing already out there.

Answer 2

Consider using something like ColorCode ; this work has already been done well, and likely more efficiently. To do this, add the NuGet package, then replace your RichTextBox with a WebBrowser control, and pass your source text into the colorizer:

using ColorCode;
[...]
webBrowser1.DocumentText = new CodeColorizer().Colorize(mySourceText, Languages.CSharp);

For info on adding NuGet packages, see here .

---

Alternatively, if you are looking for a syntax-highlighting text editor, you could use Scintilla.

First add the NuGet package called jacobslusser.ScintillaNET , and this time there's an extra step to make the control appear in the toolbox; right-click the Windows Forms toolbox, select 'Choose Items', then 'Browse', and browse to the Scintilla DLL. In my project this is here;

packages\\jacobslusser.ScintillaNET.3.6.3\\lib\\net40\\ScintillaNET.dll

That will add the 'Scintilla' control to the toolbox, and you can drag this to your form. Finally, in the form's Load event, add the following 'recipe' to make it look similar to Visual Studio's syntax highlighting:

private void Form1_Load(object sender, EventArgs e)
{
    // Configuring the default style with properties
    // we have common to every lexer style saves time.
    scintilla1.StyleResetDefault();
    scintilla1.Styles[Style.Default].Font = "Consolas";
    scintilla1.Styles[Style.Default].Size = 10;
    scintilla1.StyleClearAll();

    // Configure the CPP (C#) lexer styles
    scintilla1.Styles[Style.Cpp.Default].ForeColor = Color.Silver;
    scintilla1.Styles[Style.Cpp.Comment].ForeColor = Color.FromArgb(0, 128, 0); // Green
    scintilla1.Styles[Style.Cpp.CommentLine].ForeColor = Color.FromArgb(0, 128, 0); // Green
    scintilla1.Styles[Style.Cpp.CommentLineDoc].ForeColor = Color.FromArgb(128, 128, 128); // Gray
    scintilla1.Styles[Style.Cpp.Number].ForeColor = Color.Olive;
    scintilla1.Styles[Style.Cpp.Word].ForeColor = Color.Blue;
    scintilla1.Styles[Style.Cpp.Word2].ForeColor = Color.Blue;
    scintilla1.Styles[Style.Cpp.String].ForeColor = Color.FromArgb(163, 21, 21); // Red
    scintilla1.Styles[Style.Cpp.Character].ForeColor = Color.FromArgb(163, 21, 21); // Red
    scintilla1.Styles[Style.Cpp.Verbatim].ForeColor = Color.FromArgb(163, 21, 21); // Red
    scintilla1.Styles[Style.Cpp.StringEol].BackColor = Color.Pink;
    scintilla1.Styles[Style.Cpp.Operator].ForeColor = Color.Purple;
    scintilla1.Styles[Style.Cpp.Preprocessor].ForeColor = Color.Maroon;
    scintilla1.Lexer = Lexer.Cpp;

    // Set the keywords
    scintilla1.SetKeywords(0, "abstract as base break case catch checked continue default delegate do else event explicit extern false finally fixed for foreach goto if implicit in interface internal is lock namespace new null object operator out override params private protected public readonly ref return sealed sizeof stackalloc switch this throw true try typeof unchecked unsafe using virtual while");
    scintilla1.SetKeywords(1, "bool byte char class const decimal double enum float int long sbyte short static string struct uint ulong ushort void");

}

More about Scintilla here . Recipe from here .