c# - Intellisense 的真实准确定位

Question

我正在使用 Windows 窗体中的代码编辑器，我已经在 Richtextbox 中的“textindex”下方设置了智能感知位置

richtextbox(rtb) 用作代码编辑器， listbox(lb) 用作上下文提示。

这是预览：在此处输入图像描述使用此代码：

 //ContextHint Location
        Point point = this.rtb.GetPositionFromCharIndex(rtb.SelectionStart);

        using (Graphics g = this.rtb.CreateGraphics())
        {
            point.Y += (int)g.MeasureString(" ", rtb.Font).Height + 10; // the 10 is padding
        }
        this.lb.Location = point;
        //-------------------

但问题是我想让它像这样：

在此处输入图像描述！

如果您可以看到标签正好在 starttext 而不是 startindex 中。

我已经尝试做到了：

Point point = this.rtb.GetPositionFromCharIndex(rtb.SelectionStart - 2);

但是当我仅在richtextbox中键入2个字符时，它只是准确的，我添加它的时间再次移动，并且我添加的文本越多，它移动的越多。

现在我的问题是如何使上下文提示成为起始文本而不移动，并且当我在“空格”之后重新输入另一个单词时再次以精确文本移动。就像在实际的编译器/代码编辑器中一样。

请帮助。非常感谢！

score 1 · Accepted Answer

您必须获取当前单词开始的索引。这是一个简单的函数，它在当前选择之前查找第一个空白。您可以扩展它以匹配您想要的任何字符：

int pos;
for(pos = rtb.SelectionStart; pos > 0; --pos)
{
    if (rtb.Text[pos] == ' ')
    {
        ++pos;
        break;
    }
}
//You can now use pos as the index
Point point = this.rtb.GetPositionFromCharIndex(pos);

score 1 · Accepted Answer

您可以检查以下代码行以获得所需的内容：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;

namespace CodeEditor
{
    public partial class Form1 : Form
    {
        #region Variables
        private Dictionary<string, string> hintTexts = new Dictionary<string, string>();
        private string strCurrentHintText = null;
        private Font hintFont = new Font("Microsoft Sans Serif", 8.25f);
        private Brush hintTextColor = Brushes.Black;
        private Point hintTextLocation = new Point(2, 2);
        public Point ptCurrentCharPosition;
        Point ptHintLocation;
        int intCurrentCursorPosition = 0;
        int intCurrentSelectionLength = 0;
        List<int> lstIntLeftParenthesisCharIndexes = new List<int>();
        #endregion

        #region Properties
        #region Hint
        /// <summary>
        /// Sets the font of the hint texts.
        /// </summary>
        public Font HintFont
        {
            protected get
            {
                return hintFont;
            }
            set
            {
                hintFont = value;
            }
        }

        /// <summary>
        /// Sets the color of the hint texts.
        /// </summary>
        public Brush HintTextColor
        {
            protected get
            {
                return hintTextColor;
            }
            set
            {
                hintTextColor = value;
            }
        }

        /// <summary>
        /// Sets the location of the hint texts.
        /// </summary>
        public Point HintTextLocation
        {
            protected get
            {
                return hintTextLocation;
            }
            set
            {
                hintTextLocation = value;
            }
        }

        /// <summary>
        /// Gets and Sets the texts of the hints.
        /// </summary>
        public Dictionary<string, string> HintTexts
        {
            get
            {
                return hintTexts;
            }
            set
            {
                hintTexts = value;
            }
        }
        #endregion
        #endregion

        public Form1()
        {
            InitializeComponent();
        }

        #region Methods
        #region GetChar
        /// <summary>
        /// Specifies current char based on the cursor position.
        /// </summary>
        /// <param name="rtb">A RichTextBox control</param>
        /// <returns>Returns a char.</returns>
        public char GetChar(System.Windows.Forms.RichTextBox rtb)
        {
            return GetChar(rtb.SelectionStart, rtb);
        }

        /// <summary>
        /// Specifies a char based on the specified position.
        /// </summary>
        /// <param name="intCharIndex">A position coordinates</param>
        /// <param name="rtb">A RichTextBox control</param>
        /// <returns>Returns a char.</returns>
        public char GetChar(Point ptCurrentPosition, System.Windows.Forms.RichTextBox rtb)
        {
            return rtb.GetCharFromPosition(ptCurrentPosition);
        }

        /// <summary>
        /// Specifies a char based on the specified index.
        /// </summary>
        /// <param name="intCharIndex">A char index</param>
        /// <param name="rtb">A RichTextBox control</param>
        /// <returns>Returns a char.</returns>
        public char GetChar(int intCharIndex, System.Windows.Forms.RichTextBox rtb)
        {
            if (intCharIndex > 0 && rtb.GetPositionFromCharIndex(intCharIndex).X == 0 && rtb.GetPositionFromCharIndex(intCharIndex).Y == 0)
            {
                return '▓'; // Invalid char
            }

            if (intCharIndex != rtb.TextLength)
            {
                ptCurrentCharPosition = rtb.GetPositionFromCharIndex(intCharIndex - 1);
            }
            else
            {
                ptCurrentCharPosition = rtb.GetPositionFromCharIndex(intCharIndex);
            }
            return GetChar(ptCurrentCharPosition, rtb);
        }
        #endregion

        /// <summary>
        /// Find the text (keyword) before the specific character.
        /// </summary>
        /// <param name="rtb">A RichTextBox control</param>
        /// <param name="intKeyValue">The value of the pressed key</param>
        /// <param name="strText">The text (keyword) before last typed character for checking it</param>
        /// <returns>Returns found text (keyword).</returns>
        private string FindKeyword(System.Windows.Forms.RichTextBox rtb, int intKeyValue, string strText)
        {
            string strSelectedText = null;
            try
            {
                if (intKeyValue == 57) // ( char
                {
                    if (rtb.SelectionStart - 1 >= 0)
                    {
                        rtb.SelectionStart--;
                        rtb.SelectionLength = 1;
                    }

                    if (rtb.SelectionStart - strText.Length >= 0)
                    {
                        rtb.SelectionStart -= strText.Length;
                        rtb.SelectionLength = strText.Length;
                    }

                    strSelectedText = rtb.SelectedText;

                    if (rtb.SelectionStart - strText.Length >= 0)
                    {
                        rtb.SelectionStart += strText.Length;
                        rtb.SelectionLength = 1;
                    }

                    if (rtb.SelectionStart - 1 >= 0)
                    {
                        rtb.SelectionStart++;
                        rtb.SelectionLength = 0;
                    }
                }
            }
            catch
            {

            }

            return strSelectedText;
        }

        /// <summary>
        /// Displays a hint in the current cursor position.
        /// </summary>
        /// <param name="ttip">A ToolTip control</param>
        /// <param name="rtb">A RichTextBox control</param>
        /// <param name="intKeyValue">The value of the pressed key</param>
        /// <param name="strCheckingText">The text (keyword) before last typed character for checking it and diplaying its related hint</param>
        /// <param name="strHintText">The text of the hint for current keyword</param>
        private void ShowHint(ToolTip ttip, System.Windows.Forms.RichTextBox rtb, int intKeyValue, string strCheckingText, string strHintText)
        {
            try
            {
                if (rtb.SelectionStart - 1 >= 0)
                {
                    rtb.SelectionStart--;
                    rtb.SelectionLength = 1;
                }

                if (intKeyValue == 57) // ( char
                {
                    if (rtb.SelectionStart - strCheckingText.Length >= 0)
                    {
                        rtb.SelectionStart -= strCheckingText.Length;
                        rtb.SelectionLength = strCheckingText.Length;
                    }

                    if (rtb.SelectedText == strCheckingText)
                    {
                        rtb.SelectionStart += strCheckingText.Length;
                        rtb.SelectionLength = 1;
                        lstIntLeftParenthesisCharIndexes.Add(rtb.SelectionStart);
                    }

                    if (GetChar(lstIntLeftParenthesisCharIndexes.Last() + 1, rtb) != '(')
                    {
                        lstIntLeftParenthesisCharIndexes.Remove(lstIntLeftParenthesisCharIndexes.Count - 1);
                    }
                    ttip.ShowAlways = true;
                    ttip.OwnerDraw = true;
                    intCurrentCursorPosition = rtb.SelectionStart;
                    intCurrentSelectionLength = rtb.SelectionLength;

                    rtb.SelectionStart += rtb.SelectionLength - 1;
                    rtb.SelectionLength = 0;

                    GetChar(rtb);
                    ptHintLocation = ptCurrentCharPosition;

                    ptHintLocation.X += 2;
                    ptHintLocation.X += TextRenderer.MeasureText(rtb.Lines[0], rtb.Font).Height;

                    ptHintLocation.Y += 1;
                    ptHintLocation.Y += 2;
                    ptHintLocation.Y += TextRenderer.MeasureText(rtb.Lines[0], rtb.Font).Height;

                    rtb.SelectionStart = intCurrentCursorPosition;
                    rtb.SelectionLength = intCurrentSelectionLength;

                    strCurrentHintText = strHintText;
                    ttip.Draw += new System.Windows.Forms.DrawToolTipEventHandler(ttipHint_Draw);
                    ttip.Popup += new System.Windows.Forms.PopupEventHandler(ttipHint_Popup);

                    if (rtb.SelectionStart - strCheckingText.Length >= 0)
                    {
                        rtb.SelectionStart -= strCheckingText.Length;
                        rtb.SelectionLength = strCheckingText.Length;
                    }

                    if (rtb.SelectedText == strCheckingText)
                    {
                        rtb.SelectionStart += strCheckingText.Length;
                        rtb.SelectionStart++;
                        rtb.SelectionLength = 0;

                        try
                        {
                            HintTexts.Add(strCheckingText, strHintText);
                        }
                        catch
                        {
                            for (int intCntr = 0; intCntr < HintTexts.Count; intCntr++)
                            {
                                if (HintTexts.ElementAt(intCntr).Key == strCheckingText)
                                {
                                    strCheckingText += intCntr + 1;
                                }
                            }
                            HintTexts.Add(strCheckingText, strHintText);
                        }
                        ttip.Show(strHintText, rtb, ptHintLocation);

                        rtb.SelectionStart--;
                        rtb.SelectionLength = 1;
                    }
                }
                else if (intKeyValue == 48) // ) char
                {
                    lstIntLeftParenthesisCharIndexes.Remove(lstIntLeftParenthesisCharIndexes.Count - 1);
                    HintTexts.Remove(HintTexts.Last().Key);
                    if (lstIntLeftParenthesisCharIndexes.Count == 0)
                    {
                        ttip.ShowAlways = false;
                        ttip.RemoveAll();
                        ttip.Draw -= ttipHint_Draw;
                        ttip.Popup -= ttipHint_Popup;
                    }
                    else
                    {
                        try
                        {
                            strCurrentHintText = HintTexts.Last().Value;
                            ttip.Show(HintTexts.Last().Value, rtb, ptHintLocation);
                        }
                        catch
                        {
                            ttip.ShowAlways = false;
                            ttip.RemoveAll();
                            ttip.Draw -= ttipHint_Draw;
                            ttip.Popup -= ttipHint_Popup;
                        }
                    }
                }
                else if (intKeyValue == 13) // New Line char (Enter/Return key)
                {
                    if (ttip.ShowAlways)
                    {
                        GetChar(rtb);
                        ptHintLocation = ptCurrentCharPosition;

                        ptHintLocation.Y -= TextRenderer.MeasureText(strHintText, HintFont).Height + HintTextLocation.Y;

                        ttip.Show(strHintText, rtb, ptHintLocation);
                    }
                }
                else if (intKeyValue == 8) // Backspace key
                {
                    for (int intCntr = 0; intCntr < lstIntLeftParenthesisCharIndexes.Count; intCntr++)
                    {
                        char chr = GetChar(lstIntLeftParenthesisCharIndexes[intCntr] + 1, rtb);
                        if (GetChar(lstIntLeftParenthesisCharIndexes[intCntr] + 1, rtb) != '(')
                        {
                            lstIntLeftParenthesisCharIndexes.Remove(lstIntLeftParenthesisCharIndexes[intCntr]);
                        }
                    }

                    ttip.ShowAlways = false;
                    ttip.RemoveAll();
                    ttip.Draw -= ttipHint_Draw;
                    ttip.Popup -= ttipHint_Popup;
                }

                if (rtb.SelectionStart - 1 >= 0)
                {
                    rtb.SelectionStart++;
                    rtb.SelectionLength = 0;
                }
            }
            catch
            {
                if (intKeyValue == 8) // Backspace
                {
                    for (int intCntr = 0; intCntr < lstIntLeftParenthesisCharIndexes.Count; intCntr++)
                    {
                        char chr = GetChar(lstIntLeftParenthesisCharIndexes[intCntr] + 1, rtb);
                        if (GetChar(lstIntLeftParenthesisCharIndexes[intCntr] + 1, rtb) != '(')
                        {
                            lstIntLeftParenthesisCharIndexes.Remove(lstIntLeftParenthesisCharIndexes[intCntr]);
                        }
                    }

                    ttip.ShowAlways = false;
                    ttip.RemoveAll();
                    ttip.Draw -= ttipHint_Draw;
                    ttip.Popup -= ttipHint_Popup;
                }
            }
        }
        #endregion

        #region Events
        private void ttipHint_Popup(object sender, PopupEventArgs e)
        {
            e.ToolTipSize = new Size(TextRenderer.MeasureText(strCurrentHintText, HintFont).Width + (HintTextLocation.X * 2),
                TextRenderer.MeasureText(strCurrentHintText, HintFont).Height + (HintTextLocation.Y * 2));
        }

        private void ttipHint_Draw(object sender, DrawToolTipEventArgs e)
        {
            try
            {
                using (e.Graphics)
                {
                    e.DrawBackground();
                    e.DrawBorder();
                    e.Graphics.DrawString(strCurrentHintText, HintFont, HintTextColor, HintTextLocation);
                }
            }
            catch
            {
            }
        }

        private void rtb1_KeyUp(object sender, KeyEventArgs e)
        {
            HintFont = new Font("Arial", 9f);
            HintTextColor = Brushes.Blue;
            HintTextLocation = new Point(10, 10);

            if (FindKeyword(rtb1, e.KeyValue, "Sample1") == "Sample1")
            {
                ShowHint(ttipHint, rtb1, e.KeyValue, "Sample1", "This is an example 1.");
            }
            else if (FindKeyword(rtb1, e.KeyValue, "Sample2") == "Sample2")
            {
                ShowHint(ttipHint, rtb1, e.KeyValue, "Sample2", "This is an example 2.\nThis is an example 2. This is an example 2.");
            }
            else if (FindKeyword(rtb1, e.KeyValue, "Sample3") == "Sample3")
            {
                ShowHint(ttipHint, rtb1, e.KeyValue, "Sample3", "This is an example 3.\nThis is an example 3. This is an example 3.\nThis is an example 3. This is an example 3. This is an example 3.");
            }
            else
            {
                try
                {
                    if (e.KeyValue == 48 || e.KeyValue == 13 || e.KeyValue == 8)
                    {
                        ShowHint(ttipHint, rtb1, e.KeyValue, HintTexts.Last().Key, HintTexts.Last().Value);
                    }
                }
                catch
                {
                }
            }
        }
        #endregion
    }
}

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c# - Intellisense 的真实准确定位

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