WinForms | C# | 在文本框中间自动完成？
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时间：2020-08-06 16:31:25 来源:igfitidea点击:
WinForms | C# | AutoComplete in the Middle of a Textbox?
提问by Chaddeus
I have a textbox that does autocompletion like so:
我有一个像这样自动完成的文本框：
txtName.AutoCompleteMode = AutoCompleteMode.Suggest;
txtName.AutoCompleteSource = AutoCompleteSource.CustomSource;
txtName.AutoCompleteCustomSource = namesCollection;
It works, but only at the beginning of a textbox. I'd like autocomplete to kick in for any word the user is entering, at any position in the textbox.
它有效，但仅在文本框的开头。我希望在文本框中的任何位置自动完成用户输入的任何单词。
回答by Parimal Raj
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
namespace TubeUploader
{
public class AutoCompleteTextBox : TextBox
{
private ListBox _listBox;
private bool _isAdded;
private String[] _values;
private String _formerValue = String.Empty;
public AutoCompleteTextBox()
{
InitializeComponent();
ResetListBox();
}
private void InitializeComponent()
{
_listBox = new ListBox();
KeyDown += this_KeyDown;
KeyUp += this_KeyUp;
}
private void ShowListBox()
{
if (!_isAdded)
{
Parent.Controls.Add(_listBox);
_listBox.Left = Left;
_listBox.Top = Top + Height;
_isAdded = true;
}
_listBox.Visible = true;
_listBox.BringToFront();
}
private void ResetListBox()
{
_listBox.Visible = false;
}
private void this_KeyUp(object sender, KeyEventArgs e)
{
UpdateListBox();
}
private void this_KeyDown(object sender, KeyEventArgs e)
{
switch (e.KeyCode)
{
case Keys.Tab:
{
if (_listBox.Visible)
{
InsertWord((String)_listBox.SelectedItem);
ResetListBox();
_formerValue = Text;
}
break;
}
case Keys.Down:
{
if ((_listBox.Visible) && (_listBox.SelectedIndex < _listBox.Items.Count - 1))
_listBox.SelectedIndex++;
break;
}
case Keys.Up:
{
if ((_listBox.Visible) && (_listBox.SelectedIndex > 0))
_listBox.SelectedIndex--;
break;
}
}
}
protected override bool IsInputKey(Keys keyData)
{
switch (keyData)
{
case Keys.Tab:
return true;
default:
return base.IsInputKey(keyData);
}
}
private void UpdateListBox()
{
if (Text == _formerValue) return;
_formerValue = Text;
String word = GetWord();
if (_values != null && word.Length > 0)
{
String[] matches = Array.FindAll(_values,
x => (x.StartsWith(word, StringComparison.OrdinalIgnoreCase) && !SelectedValues.Contains(x)));
if (matches.Length > 0)
{
ShowListBox();
_listBox.Items.Clear();
Array.ForEach(matches, x => _listBox.Items.Add(x));
_listBox.SelectedIndex = 0;
_listBox.Height = 0;
_listBox.Width = 0;
Focus();
using (Graphics graphics = _listBox.CreateGraphics())
{
for (int i = 0; i < _listBox.Items.Count; i++)
{
_listBox.Height += _listBox.GetItemHeight(i);
// it item width is larger than the current one
// set it to the new max item width
// GetItemRectangle does not work for me
// we add a little extra space by using '_'
int itemWidth = (int)graphics.MeasureString(((String)_listBox.Items[i]) + "_", _listBox.Font).Width;
_listBox.Width = (_listBox.Width < itemWidth) ? itemWidth : _listBox.Width;
}
}
}
else
{
ResetListBox();
}
}
else
{
ResetListBox();
}
}
private String GetWord()
{
String text = Text;
int pos = SelectionStart;
int posStart = text.LastIndexOf(' ', (pos < 1) ? 0 : pos - 1);
posStart = (posStart == -1) ? 0 : posStart + 1;
int posEnd = text.IndexOf(' ', pos);
posEnd = (posEnd == -1) ? text.Length : posEnd;
int length = ((posEnd - posStart) < 0) ? 0 : posEnd - posStart;
return text.Substring(posStart, length);
}
private void InsertWord(String newTag)
{
String text = Text;
int pos = SelectionStart;
int posStart = text.LastIndexOf(' ', (pos < 1) ? 0 : pos - 1);
posStart = (posStart == -1) ? 0 : posStart + 1;
int posEnd = text.IndexOf(' ', pos);
String firstPart = text.Substring(0, posStart) + newTag;
String updatedText = firstPart + ((posEnd == -1) ? "" : text.Substring(posEnd, text.Length - posEnd));
Text = updatedText;
SelectionStart = firstPart.Length;
}
public String[] Values
{
get
{
return _values;
}
set
{
_values = value;
}
}
public List<String> SelectedValues
{
get
{
String[] result = Text.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
return new List<String>(result);
}
}
}
}
Sample Usage
示例用法
using System;
using System.Windows.Forms;
namespace AutoComplete
{
public partial class TestForm : Form
{
private readonly String[] _values = { "one", "two", "three", "tree", "four", "fivee" };
public TestForm()
{
InitializeComponent();
// AutoComplete is our special textbox control on the form
AutoComplete.Values = _values;
}
}
}
回答by Francisco Goldenstein
I made a few changes to the solution proposed by @PaRiMaL RaJ because the list box was not being displayed when the text box was inside a UserControl that was not tall enough. Basically, instead of adding the list box to the parent of the text box, I added to the form and I calculate the absolute position in the form.
我对@PaRiMaL RaJ 提出的解决方案进行了一些更改，因为当文本框位于不够高的 UserControl 内时，列表框未显示。基本上，我没有将列表框添加到文本框的父级，而是添加到表单中并计算表单中的绝对位置。
public class AutoCompleteTextBox : TextBox
{
private ListBox _listBox;
private bool _isAdded;
private String[] _values;
private String _formerValue = String.Empty;
public AutoCompleteTextBox()
{
InitializeComponent();
ResetListBox();
}
private void InitializeComponent()
{
_listBox = new ListBox();
this.KeyDown += this_KeyDown;
this.KeyUp += this_KeyUp;
}
private void ShowListBox()
{
if (!_isAdded)
{
Form parentForm = this.FindForm(); // new line added
parentForm.Controls.Add(_listBox); // adds it to the form
Point positionOnForm = parentForm.PointToClient(this.Parent.PointToScreen(this.Location)); // absolute position in the form
_listBox.Left = positionOnForm.X;
_listBox.Top = positionOnForm.Y + Height;
_isAdded = true;
}
_listBox.Visible = true;
_listBox.BringToFront();
}
private void ResetListBox()
{
_listBox.Visible = false;
}
private void this_KeyUp(object sender, KeyEventArgs e)
{
UpdateListBox();
}
private void this_KeyDown(object sender, KeyEventArgs e)
{
switch (e.KeyCode)
{
case Keys.Enter:
case Keys.Tab:
{
if (_listBox.Visible)
{
Text = _listBox.SelectedItem.ToString();
ResetListBox();
_formerValue = Text;
this.Select(this.Text.Length, 0);
e.Handled = true;
}
break;
}
case Keys.Down:
{
if ((_listBox.Visible) && (_listBox.SelectedIndex < _listBox.Items.Count - 1))
_listBox.SelectedIndex++;
e.Handled = true;
break;
}
case Keys.Up:
{
if ((_listBox.Visible) && (_listBox.SelectedIndex > 0))
_listBox.SelectedIndex--;
e.Handled = true;
break;
}
}
}
protected override bool IsInputKey(Keys keyData)
{
switch (keyData)
{
case Keys.Tab:
if (_listBox.Visible)
return true;
else
return false;
default:
return base.IsInputKey(keyData);
}
}
private void UpdateListBox()
{
if (Text == _formerValue)
return;
_formerValue = this.Text;
string word = this.Text;
if (_values != null && word.Length > 0)
{
string[] matches = Array.FindAll(_values,
x => (x.ToLower().Contains(word.ToLower())));
if (matches.Length > 0)
{
ShowListBox();
_listBox.BeginUpdate();
_listBox.Items.Clear();
Array.ForEach(matches, x => _listBox.Items.Add(x));
_listBox.SelectedIndex = 0;
_listBox.Height = 0;
_listBox.Width = 0;
Focus();
using (Graphics graphics = _listBox.CreateGraphics())
{
for (int i = 0; i < _listBox.Items.Count; i++)
{
if (i < 20)
_listBox.Height += _listBox.GetItemHeight(i);
// it item width is larger than the current one
// set it to the new max item width
// GetItemRectangle does not work for me
// we add a little extra space by using '_'
int itemWidth = (int)graphics.MeasureString(((string)_listBox.Items[i]) + "_", _listBox.Font).Width;
_listBox.Width = (_listBox.Width < itemWidth) ? itemWidth : this.Width; ;
}
}
_listBox.EndUpdate();
}
else
{
ResetListBox();
}
}
else
{
ResetListBox();
}
}
public String[] Values
{
get
{
return _values;
}
set
{
_values = value;
}
}
public List<String> SelectedValues
{
get
{
String[] result = Text.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
return new List<String>(result);
}
}
}
回答by codah
The other solutions didn't work for me in a multiline environment to my needs, so I've added to @Francisco Goldenstein's answer to enable this. What I needed was to autocomplete any 'word' in the TextBox and in any position/line. After minimal testing, this class seems to work well enough for me in a multiline TextBox. Hope it helps someone.
其他解决方案在满足我需求的多行环境中对我不起作用，因此我已将其添加到@Francisco Goldenstein 的答案中以启用此功能。我需要的是自动完成文本框中和任何位置/行中的任何“单词”。经过最少的测试，这个类在多行文本框中对我来说似乎足够好。希望它可以帮助某人。
Main changes are in UpdateListBox()and this_KeyDown(), to deal with the 'current' word, i.e. the one just before the caret position, rather than the entire textbox contents.
主要变化在UpdateListBox()and 中this_KeyDown()，以处理“当前”单词，即插入符号位置之前的单词，而不是整个文本框内容。
Change the definition of separatorsin UpdateListBox()to suit your needs.
更改separatorsin的定义UpdateListBox()以满足您的需要。
using System;
using System.Drawing;
using System.Windows.Forms;
class MultiLineAutoCompleteTextBox : TextBox
{
private ListBox _listBox;
private bool _isAdded;
private String[] _values;
private String _formerValue = String.Empty;
private int _prevBreak;
private int _nextBreak;
private int _wordLen;
public MultiLineAutoCompleteTextBox()
{
InitializeComponent();
ResetListBox();
}
private void InitializeComponent()
{
_listBox = new ListBox();
KeyDown += this_KeyDown;
KeyUp += this_KeyUp;
}
private void ShowListBox()
{
if (!_isAdded)
{
Form parentForm = FindForm();
if (parentForm == null) return;
parentForm.Controls.Add(_listBox);
Point positionOnForm = parentForm.PointToClient(Parent.PointToScreen(Location));
_listBox.Left = positionOnForm.X;
_listBox.Top = positionOnForm.Y + Height;
_isAdded = true;
}
_listBox.Visible = true;
_listBox.BringToFront();
}
private void ResetListBox()
{
_listBox.Visible = false;
}
private void this_KeyUp(object sender, KeyEventArgs e)
{
UpdateListBox();
}
private void this_KeyDown(object sender, KeyEventArgs e)
{
switch (e.KeyCode)
{
case Keys.Enter:
case Keys.Tab:
case Keys.Space:
{
if (_listBox.Visible)
{
Text = Text.Remove(_prevBreak == 0 ? 0 : _prevBreak + 1, _prevBreak == 0 ? _wordLen + 1 : _wordLen);
Text = Text.Insert(_prevBreak == 0 ? 0 : _prevBreak + 1, _listBox.SelectedItem.ToString());
ResetListBox();
_formerValue = Text;
Select(Text.Length, 0);
e.Handled = true;
}
break;
}
case Keys.Down:
{
if ((_listBox.Visible) && (_listBox.SelectedIndex < _listBox.Items.Count - 1))
_listBox.SelectedIndex++;
e.Handled = true;
break;
}
case Keys.Up:
{
if ((_listBox.Visible) && (_listBox.SelectedIndex > 0))
_listBox.SelectedIndex--;
e.Handled = true;
break;
}
}
}
protected override bool IsInputKey(Keys keyData)
{
switch (keyData)
{
case Keys.Tab:
if (_listBox.Visible)
return true;
else
return false;
default:
return base.IsInputKey(keyData);
}
}
private void UpdateListBox()
{
if (Text == _formerValue) return;
if (Text.Length == 0)
{
_listBox.Visible = false;
return;
}
_formerValue = Text;
var separators = new[] { '|', '[', ']', '\r', '\n', ' ', '\t' };
_prevBreak = Text.LastIndexOfAny(separators, CaretIndex > 0 ? CaretIndex - 1 : 0);
if (_prevBreak < 1) _prevBreak = 0;
_nextBreak = Text.IndexOfAny(separators, _prevBreak + 1);
if (_nextBreak == -1) _nextBreak = CaretIndex;
_wordLen = _nextBreak - _prevBreak - 1;
if (_wordLen < 1) return;
string word = Text.Substring(_prevBreak + 1, _wordLen);
if (_values != null && word.Length > 0)
{
string[] matches = Array.FindAll(_values,
x => (x.ToLower().Contains(word.ToLower())));
if (matches.Length > 0)
{
ShowListBox();
_listBox.BeginUpdate();
_listBox.Items.Clear();
Array.ForEach(matches, x => _listBox.Items.Add(x));
_listBox.SelectedIndex = 0;
_listBox.Height = 0;
_listBox.Width = 0;
Focus();
using (Graphics graphics = _listBox.CreateGraphics())
{
for (int i = 0; i < _listBox.Items.Count; i++)
{
if (i < 20)
_listBox.Height += _listBox.GetItemHeight(i);
// it item width is larger than the current one
// set it to the new max item width
// GetItemRectangle does not work for me
// we add a little extra space by using '_'
int itemWidth = (int)graphics.MeasureString(((string)_listBox.Items[i]) + "_", _listBox.Font).Width;
_listBox.Width = (_listBox.Width < itemWidth) ? itemWidth : Width; ;
}
}
_listBox.EndUpdate();
}
else
{
ResetListBox();
}
}
else
{
ResetListBox();
}
}
public int CaretIndex => SelectionStart;
public String[] Values
{
get
{
return _values;
}
set
{
_values = value;
}
}
}
