RichTextBox选择和选择颜色不起作用

问题描述

我有一种方法可以检测用户名，将其突出显示并更改其颜色，然后将其放入RichTextBox中：

I have a method that detects the username, highlights it and changes it's color and then puts it in the RichTextBox:

    private void displayMessage(string message, string color)
    {
        string username = message.Substring(0, message.IndexOf(':') - 1);
        string realMessage = message.Replace(username , "");

        serverChat.Text += message;
        serverChat.Select(((serverChat.Text.Length - message.Length) - 1), username.Length - 1);

        serverChat.SelectionColor = getColor(color);
        serverChat.Text += Environment.NewLine;
    }

    private void sendButton_Click(object sender, EventArgs e)
    {
        displayMessage("PersonX: Hey is it working for you?", "1");
        displayMessage("PersonY: Yeah, it just started. Thanks!", "0");
    }
    private Color getColor(string index)
    {
        switch (index)
        {
            case "0":
                return Color.Red;
            case "1":
                return Color.Blue;
            case "2":
                return Color.Green;
            case "3":
                return Color.Yellow;
            case "4":
                return Color.Black;
            default:
                return Color.Black;
        }
    }

结果是我收到了所有文本返回红色。有什么我做错的事情或什么原因使它无法工作？

The results is that I get all of the text coming back the color red. Is there anything that I did wrong or any reason that it would not be working?

推荐答案

您的错误是添加了按摩文字直接发送到RichTextBox.Text。

Your mistake is to add the massage text to the RichTextBox.Text dircetly. This will loose or mess up all the formatting you had achieved before.

相反，您必须使用特殊功能 AppendText ：

Instead you must use the specialized function AppendText:

serverChat.AppendText(message);

和

serverChat.AppendText(Environment.NewLine);

这将保留以前的格式。

此外，您的选择还有点不足。当您以空文本开头并且用户名输入不正确时，它会崩溃。尝试以下操作：

Also your selection is a bit off. It crashes when you start with an empty text and doesn't quite get the usernames right. Try this:

string username = message.Substring(0, message.IndexOf(':') );
string realMessage = message.Replace(username , "");
serverChat.AppendText(message);
serverChat.Select(((serverChat.Text.Length - message.Length)), username.Length );
//..

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