在 RichEditBox 中突出显示单词 [英] Highlighting words in RichEditBox

问题描述

需要对文档 RichEditBox 中的子字符串进行五色高亮.为此我写了一个方法:

It is needed to highlight by fiven colour a substring in the document RichEditBox. For this purpose I wrote a method:

private async Task ChangeTextColor(string text, Color color)
{
    string textStr;
    bool theEnd = false;
    int startTextPos = 0;
    myRichEdit.Document.GetText(TextGetOptions.None, out textStr);

    while (theEnd == false)
    {
        myRichEdit.Document.GetRange(startTextPos, textStr.Length).GetText(TextGetOptions.None, out textStr);
        var isFinded = myRichEdit.Document.GetRange(startTextPos, textStr.Length).FindText(text, textStr.Length, FindOptions.None);

        if (isFinded != 0)
        {
            string textStr2;
            textStr2 = myRichEdit.Document.Selection.Text;

            var dialog = new MessageDialog(textStr2);
            await dialog.ShowAsync();

            myRichEdit.Document.Selection.CharacterFormat.BackgroundColor = color;
            startTextPos = myRichEdit.Document.Selection.EndPosition;
            myRichEdit.Document.ApplyDisplayUpdates();
        }
        else
        {
            theEnd = true;
        }
    } 
}

在调试器中，您可以看到有一个子字符串，并且 isFinded 与找到的子字符串中的符号(或符号)数量相等.这意味着找到了片段，根据方法 FindText 的描述判断应该突出显示，但事实并非如此.在 textStr2 中返回一个空行，相应地，颜色不会改变.我无法确定错误的原因.

In the debugger you can see that there is a substring and isFinded is equal with the number of signs (or symbols) in the found substring. It means the fragment is found and judging by the description of the method FindText should be highlighted but it isn't. In textStr2 an empty line returns and, correspondingly, the colour doesn't change. I cannot identify the reasons of the error.

推荐答案

您发布的代码没有设置选择，所以 myRichEdit.Document.Selection 为空.您可以使用 ITextRange.SetRange 设置选择.您可以使用 ITextRange.FindText 方法 找到选择中的字符串.

The code you postted did not set the selection, so the myRichEdit.Document.Selection is null. You can use ITextRange.SetRange to set the selection. And you can use ITextRange.FindText method to find the string in the selection.

例如:

private void ChangeTextColor(string text, Color color)
{
    string textStr;

    myRichEdit.Document.GetText(TextGetOptions.None, out textStr);

    var myRichEditLength = textStr.Length;

    myRichEdit.Document.Selection.SetRange(0, myRichEditLength);
    int i = 1;
    while (i > 0)
    {
        i = myRichEdit.Document.Selection.FindText(text, myRichEditLength, FindOptions.Case);

        ITextSelection selectedText = myRichEdit.Document.Selection;
        if (selectedText != null)
        {
            selectedText.CharacterFormat.BackgroundColor = color;
        }
    }
}

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