C# 组合框搜索列表中的任意位置，而不仅仅是使用数据表筛选器的第一个字母
本文关键字：数据表 筛选 第一个 不仅仅是 搜索 组合 列表 位置 任意 | 更新日期: 2023-09-27 18:32:00
我想实现组合框（搜索列表中的任何地方，而不仅仅是第一个字母）。 我在这里看到了这个，但没有帮助我。
我使用以下代码
private void cmbMenuName_TextChanged(object sender, EventArgs e)
{
DataTable dt = dtMenuOriginal;//dtMenuOriginal-Orginal data
dt.DefaultView.RowFilter = string.Format("MenuName LIKE '%{0}%'", cmbMenuName.Text);
cmbMenuName.DataSource = dt;
}
此代码仅适用于第一个字符 按请告诉我我将在哪个事件上调用或任何其他解决此问题的方法
我使用此链接，这对于自动完成文本框控件很有用。我的代码-
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Collections;
namespace Combo_MiddleText_AutocompleteDemo
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
//don't forget to create/initialize our own autocomplete listbox
this.InitializeAutoComplete();
}
private void InitializeAutoComplete()
{
this.SuspendLayout();
//Create a new listbox that will be shown for the auto-complete
//
// _listBox
//
_listBox = new System.Windows.Forms.ListBox();
_listBox.Visible = false;
_listBox.Location = new System.Drawing.Point(0, 0);
_listBox.Name = "_listBox";
_listBox.Size = new System.Drawing.Size(120, 96);
_listBox.TabIndex = 0;
_listBox.MouseDown += new System.Windows.Forms.MouseEventHandler(this._listBox_MouseDown);
//
// AutoCompleteTextBox - attach some events
//
cmbMenuName.KeyDown += new System.Windows.Forms.KeyEventHandler(this.cmbMenuName_KeyDown);
cmbMenuName.KeyUp += new System.Windows.Forms.KeyEventHandler(this.cmbMenuName_KeyUp);
this.ResumeLayout(false);
}
#region Variables
Hashtable hash;
private String[] _values;
private ListBox _listBox;
private bool _isAdded;
private String _formerValue = String.Empty;
#endregion Variables
private void Form1_Load(object sender, EventArgs e)
{
FillGrid(125);// Menu combobox in Quotation Menu Grid
cmbMenuName.DroppedDown = false;
}
public DataTable FillGrid(int QueryNo)
{
try
{
hash = new Hashtable();
DataTable dtReturn = new DataTable();
hash.Add("@QueryNo", QueryNo);
//dtReturn= ClsDefination.FillData()
dtReturn = ClsDefination.FillData("[usp_Transaction_QuotationMaster_Select]", hash);
if ((dtReturn != null && dtReturn.Rows.Count > 0))// || dtReturn2 != null && dtReturn2.Rows.Count > 0)
{
DataRow objRow = dtReturn.Rows[0];
if (QueryNo == 125) // Menu Name
{
cmbMenuName.DataSource = dtReturn;
cmbMenuName.DisplayMember = "MenuName";
cmbMenuName.ValueMember = "MenuID";
cmbMenuName.Text = "";
List<string> list = new List<string>();
for (int i = 0; i < dtReturn.Rows.Count; i++)
{
DataRow dr = dtReturn.Rows[i];
list.Add(dr["MenuName"].ToString());
}
_values = list.ToArray();
}
}
else
{
}
return null;
}
catch (Exception)
{
return null;
throw;
}
}
private void cmbMenuName_KeyDown(object sender, KeyEventArgs e)
{
//react the arrow up and down
switch (e.KeyCode)
{
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;
}
}
}
private void cmbMenuName_KeyUp(object sender, KeyEventArgs e)
{
//whenever a key is pressed, update the listbox content
UpdateListBox();
}
private void _listBox_MouseDown(object sender, MouseEventArgs e)
{
//select the item with the mouse
if (_listBox.Visible)
{
InsertWord((String)_listBox.SelectedItem);
HideListBox();
_formerValue = cmbMenuName.Text;
}
}
private void HideListBox()
{
//Hide the listbox
_listBox.Visible = false;
}
//private void btnShow_Click(object sender, EventArgs e)
//{
// //when this button is clicked,
// //we take the values from the textbox and list them into the second listbox
// lstSelectedValues.Items.Clear();
// List<String> selectedValues = SelectedValues;
// Array.ForEach(selectedValues.ToArray(),
// selectedValue => lstSelectedValues.Items.Add(selectedValue.Trim()));
//}
public List<String> SelectedValues
{
get
{
//return the list of selection
String[] result = cmbMenuName.Text.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
return new List<String>(result);
}
}
private void UpdateListBox()
{
//fill the listbox with the new filtered values
if (cmbMenuName.Text != _formerValue)
{
_formerValue = cmbMenuName.Text;
String word = GetWord();
if (word.Length > 0)
{
//case insensitive search
String[] matches = Array.FindAll(_values, x => (x.ToUpper().Contains(word.ToUpper()) && !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;
//at least the same width as the textbox
_listBox.Width = cmbMenuName.Width;
// cmbMenuName.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
{
HideListBox();
}
}
else
{
HideListBox();
}
}
}
private void ShowListBox()
{
//display the listbox just below the textbox
if (!_isAdded)
{
this.Controls.Add(_listBox);
_listBox.Left = cmbMenuName.Left;
_listBox.Top = cmbMenuName.Top + cmbMenuName.Height;
_isAdded = true;
}
_listBox.Visible = true;
}
private String GetWord()
{
//get the current word (useful when there is more than one on the textbox)
String text = cmbMenuName.Text;
int pos = cmbMenuName.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)
{
//add the new selection to the textbox
String text = cmbMenuName.Text;
int pos = cmbMenuName.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));
cmbMenuName.Text = updatedText;
cmbMenuName.SelectionStart = firstPart.Length;
}
private void cmbMenuName_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
if ((e.KeyCode == Keys.Tab) && (_listBox.Visible))
{
InsertWord((String)_listBox.SelectedItem);
HideListBox();
_formerValue = cmbMenuName.Text;
}
}
private void cmbMenuName_KeyDown_1(object sender, KeyEventArgs e)
{
e.Handled = true;
}
您也可以参考此链接。它在 c++ 中使用了一些事件处理程序来构建 toolstripcombobox。Toolstripcombobox在某种程度上类似于combobox，因为它只是从combobox继承而来的，.net中的c ++和c#似乎很相似，所以你理解代码的概念不会有太大问题。