c# - 从类中创建属性

Question

我创建了一个类，它可以缩短文本以适合文本框，同时还添加“...”。

例子:

[ThisTextis]toolong > [ThisTex...]

我在 Windows 8.1 VM(虚拟机)上使用 Microsoft Visual Studio 2013，该软件是一个应用程序。

现在它可能并不完美，但效果非常好。我现在想知道的是，我是否可以从该类中创建一个 bool 属性，以便用户可以在 XAML 中的文本框上启用/禁用它:

<TextBox CutText="True"/>

问题是我已经在类中使用了预先存在的 Text 属性，我的代码没有我希望的那么漂亮。无论如何，我很乐意提供任何建议和/或帮助。

编辑:简单地说，我想为 TextBox 创建一个 TextBlock.TextTrimming 属性，因为已经存在的属性仅限于 TextBlock .

这是类:

 class CutText
    {
        //Create a new instance of a textbox
        TextBox textCut = new TextBox();

        //Reset at start
        public void ResetText(TextBox text)
        {
            //Overwrite textCut with the chosen TextBox
            textCut = text;
            //Handles the possibility of already filled textbox
            if (textCut.Text != "" || textCut.Text != null)
            {
                _text = textCut.Text;
            }
            //Prevents text from being 'Null' 
            else
            {
                _text = "";
            }
        }

        //Cuts text to width of textbox
        private string CutTextToWidth(string text, double fontSize, double width)
        {
            //boolean to check if width of text is correct
            bool validArea = false;
            //comply with difference in width of characters 
            double CharDiffLength = (stringWidth("M", fontSize) - stringWidth("|", fontSize));
            //shortened text
            string shortText = text;
            //last length which was too long
            int LastLongLen = text.Length;
            //last length which fit into textbox
            int LastFitLen = 0; 

            if (stringWidth(text, fontSize) < width)
            {
                shortText = text;
            }
            else
            {
                //repeat until the text fits into the appointed area
                while (!validArea)
                {
                    if (width < stringWidth(shortText, fontSize))
                    {
                        //text is still too long
                        LastLongLen = shortText.Length;
                    }
                    else
                    {
                        //text is not too long
                        LastFitLen = shortText.Length;
                    }

                    int newLen = (LastFitLen + LastLongLen) / 2;

                    if (shortText.Length != newLen)
                    {
                        //set shortened text
                        shortText = text.Substring(0, newLen) + "\u2026";
                    }
                    validArea = ((width - 10 < stringWidth(shortText, fontSize)) && (stringWidth(shortText, fontSize) < width));
                }
            }
            //return the shortened text
            return shortText;
        }

        //Calculate the width of the text
        private double stringWidth(string s, double fontSize)
        {
            if (s == " ")
                s = "\u00a0";

            TextBlock t = new TextBlock()
            {
                FontSize = fontSize,
                Text = s
            };
            t.Measure(new Size(double.MaxValue, double.MaxValue));
            return t.ActualWidth;
        }

        //(GotFocus) Replaces cut text with full text and places the cursor at the chosen position
        public void GotFocusText()
        {
            int index = textCut.SelectionStart;
            textCut.Text = _text;
            textCut.SelectionStart = index;
        }

        //(LostFocus) Saves cut text into property / empties the textbox if nothing has been written and sets tooltip
        public void LostFocusText()
        {
            if (!string.IsNullOrWhiteSpace(textCut.Text))
            {
                Text = textCut.Text;
            }
            else
            {
                Text = "";
            }
            ToolTipService.SetToolTip(textCut, _text);
        }

        //TextBox.Text Property
        private string _text;
        public string Text
        {
            get { return _text; }
            set
            {
                _text = value;
                //Receive text, fontsize and width of textbox
                textCut.Text = CutTextToWidth(_text, textCut.FontSize, textCut.Width - 25);
            }
        }
    }

Answer 1

很遗憾地通知您，您浪费了时间。 WPF 已经内置了该功能。您可以设置 TextBlock.TextTrimming property到 CharacterEllipsis 或 WordEllipsis ，这将自动修剪控件的溢出文本并添加省略号 (...)。看这个简单的例子:

<TextBlock TextTrimming="CharacterEllipsis" Width="150">
    Lorem ipsum dolor sit amet, consectetur adipisicing</TextBlock>

来自TextTrimming Enumeration MSDN 上的页面:

CharacterEllipsis: Text is trimmed at a character boundary. An ellipsis (...) is drawn in place of remaining text.

WordEllipsis: Text is trimmed at a word boundary. An ellipsis (...) is drawn in place of remaining text.

---

更新>>>

要更直接地回答您的问题，您应该在 Attached Property 中创建代码.这样，您可以定义一个 bool 附加属性来使用省略号，例如。像这样:

<TextBox TextBoxProperties.CutText="True" />

... 其中 TextBoxProperties 是定义附加属性的类的名称，CutText 是属性本身的名称。查看How to create an Attached Property section从链接页面找出如何做到这一点。您可以使用该属性中的 CutText 类。