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In one of my WinForms applications, I have a window with a ComboBox for the user to select a customer from.
The customers in this list box are in this format : "CustomerID - CustomerName", for example "004540 - NorthWind Traders"
The native WinForms combobox has an autocomplete feature built-in and it works well: the problem is that it only works by matching from the beginning of the string of each item of the combobox's list and not from anywhere (substring).
What I would like my users to be able to do is to either type of the CustomerID or CustomerName, as senior users are familiar with most CustomerIDs while new recruits would benefit from being able to type the CustomerName in and get the AutoComplete anyway. That means that I actually want to look for the best match from the list where the inputted text is a substring of the ComboBox item.
A solution often suggested for this kind of scenario is to create a hidden list box that only shows up when the user types, but I'm not happy with that as it feels like a quick hack and is not easily reusable, and may look and behave inconsistently compared to the standard ComboBox control.
I've tried to implement this myself using the DroppedDown property to make the list appear and use SelectedIndex to set the item but the content of the combobox's textbox is reset when I do that, while I only would like the "best matching item" to be highlighted from the ComboBox lists (I need "Suggest" and not "Append", Append-mode can not be really be used with substring-matching anyway).
I think that there must be a better way? If anyone knows of a custom / 3rd Party control doing this, I'm not against buying one either.
Thanks.
PS: I am programming in C# for WinForms, with .Net Framework 3.5.
950
Here is the C# version. It has a lot of options to it.
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;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
this.Load += new EventHandler(this.Form1_Load);
InitializeComponent();
}
private clsCustomAutoCompleteTextbox ClsCustomAutoCompleteTextbox1 = null;
private List<string> MasterList = new List<string> ();
public void Form1_Load(object sender, System.EventArgs e) {
this.ClsCustomAutoCompleteTextbox1 = new clsCustomAutoCompleteTextbox();
this.ClsCustomAutoCompleteTextbox1.AutoCompleteFormBorder = System.Windows.Forms.FormBorderStyle.None;
this.ClsCustomAutoCompleteTextbox1.AutoCompleteList = null;
this.ClsCustomAutoCompleteTextbox1.Location = new System.Drawing.Point(27, 57);
this.ClsCustomAutoCompleteTextbox1.Name = "clsCustomAutoCompleteTextbox1";
this.ClsCustomAutoCompleteTextbox1.OnEnterSelect = true;
this.ClsCustomAutoCompleteTextbox1.SelectionMethods = clsCustomAutoCompleteTextbox.SelectOptions.OnEnterSingleClick;
this.ClsCustomAutoCompleteTextbox1.SelectTextAfterItemSelect = true;
this.ClsCustomAutoCompleteTextbox1.ShowAutoCompleteOnFocus = false;
this.ClsCustomAutoCompleteTextbox1.Size = new System.Drawing.Size(232, 20);
this.ClsCustomAutoCompleteTextbox1.TabIndex = 0;
this.Controls.Add(this.ClsCustomAutoCompleteTextbox1);
this.ClsCustomAutoCompleteTextbox1.BeforeDisplayingAutoComplete +=
new EventHandler<clsCustomAutoCompleteTextbox.clsAutoCompleteEventArgs>(BeforeDisplayingAutoComplete);
List<string> L;
L = new List<string>();
L.Add("123123 - Bob");
L.Add("534543 - Sally");
L.Add("123123 - George");
L.Add("34213 - Happy");
MasterList = L;
this.ClsCustomAutoCompleteTextbox1.AutoCompleteList = L;
}
private void BeforeDisplayingAutoComplete(object sender, clsCustomAutoCompleteTextbox.clsAutoCompleteEventArgs e) {
string Name = this.ClsCustomAutoCompleteTextbox1.Text.ToLower();
List<string> Display = new List<string> ();
foreach (string Str in MasterList) {
if ((Str.ToLower().IndexOf(Name) > -1)) {
Display.Add(Str);
}
}
e.AutoCompleteList = Display;
e.SelectedIndex = 0;
}
}
public class clsCustomAutoCompleteTextbox : TextBox
{
private bool First = true;
private object sender;
private clsAutoCompleteEventArgs e;
public List<string> test = new List<string> ();
public int Tabs = 0;
private int mSelStart;
private int mSelLength;
private List<string> myAutoCompleteList = new List<string> ();
private ListBox myLbox = new ListBox();
private Form myForm = new Form();
private Form myParentForm;
private bool DontHide = false;
private bool SuspendFocus = false;
private clsAutoCompleteEventArgs Args;
private Timer HideTimer = new Timer();
private Timer FocusTimer = new Timer();
private bool myShowAutoCompleteOnFocus;
private System.Windows.Forms.FormBorderStyle myAutoCompleteFormBorder = FormBorderStyle.None;
private bool myOnEnterSelect;
private int LastItem;
private SelectOptions mySelectionMethods = (SelectOptions.OnDoubleClick | SelectOptions.OnEnterPress);
private bool mySelectTextAfterItemSelect = true;
private List<string> value;
private int Cnt = 0;
public bool SelectTextAfterItemSelect
{
get
{
return mySelectTextAfterItemSelect;
}
set
{
mySelectTextAfterItemSelect = value;
}
}
[System.ComponentModel.Browsable(false)]
public SelectOptions SelectionMethods
{
get
{
return mySelectionMethods;
}
set
{
mySelectionMethods = value;
}
}
public bool OnEnterSelect
{
get
{
return myOnEnterSelect;
}
set
{
myOnEnterSelect = value;
}
}
public System.Windows.Forms.FormBorderStyle AutoCompleteFormBorder
{
get
{
return myAutoCompleteFormBorder;
}
set
{
myAutoCompleteFormBorder = value;
}
}
public bool ShowAutoCompleteOnFocus
{
get
{
return myShowAutoCompleteOnFocus;
}
set
{
myShowAutoCompleteOnFocus = value;
}
}
public ListBox Lbox
{
get
{
return myLbox;
}
}
public List<string> AutoCompleteList { get; set; }
public event EventHandler<clsAutoCompleteEventArgs> BeforeDisplayingAutoComplete;
public event EventHandler<clsItemSelectedEventArgs> ItemSelected;
public enum SelectOptions
{
None = 0,
OnEnterPress = 1,
OnSingleClick = 2,
OnDoubleClick = 4,
OnTabPress = 8,
OnRightArrow = 16,
OnEnterSingleClick = 3,
OnEnterSingleDoubleClicks = 7,
OnEnterDoubleClick = 5,
OnEnterTab = 9,
}
public class clsAutoCompleteEventArgs : EventArgs
{
private List<string> myAutoCompleteList;
private bool myCancel;
private int mySelectedIndex;
private List<string> value;
public int SelectedIndex
{
get
{
return mySelectedIndex;
}
set
{
mySelectedIndex = value;
}
}
public bool Cancel
{
get
{
return myCancel;
}
set
{
myCancel = value;
}
}
public List<string> AutoCompleteList { get; set; }
}
public override string SelectedText
{
get
{
return base.SelectedText;
}
set
{
base.SelectedText = value;
}
}
public override int SelectionLength
{
get
{
return base.SelectionLength;
}
set
{
base.SelectionLength = value;
}
}
public clsCustomAutoCompleteTextbox()
{
HideTimer.Tick += new EventHandler(HideTimer_Tick);
FocusTimer.Tick += new EventHandler(FocusTimer_Tick);
myLbox.Click += new EventHandler(myLbox_Click);
myLbox.DoubleClick += new EventHandler(myLbox_DoubleClick);
myLbox.GotFocus += new EventHandler(myLbox_GotFocus);
myLbox.KeyDown += new KeyEventHandler(myLbox_KeyDown);
myLbox.KeyUp += new KeyEventHandler(myLbox_KeyUp);
myLbox.LostFocus += new EventHandler(myLbox_LostFocus);
myLbox.MouseClick += new MouseEventHandler(myLbox_MouseClick);
myLbox.MouseDoubleClick += new MouseEventHandler(myLbox_MouseDoubleClick);
myLbox.MouseDown += new MouseEventHandler(myLbox_MouseDown);
this.GotFocus += new EventHandler(clsCustomAutoCompleteTextbox_GotFocus);
this.KeyDown += new KeyEventHandler(clsCustomAutoCompleteTextbox_KeyDown);
this.Leave += new EventHandler(clsCustomAutoCompleteTextbox_Leave);
this.LostFocus += new EventHandler(clsCustomAutoCompleteTextbox_LostFocus);
this.Move += new EventHandler(clsCustomAutoCompleteTextbox_Move);
this.ParentChanged += new EventHandler(clsCustomAutoCompleteTextbox_ParentChanged);
}
override protected void OnKeyUp(System.Windows.Forms.KeyEventArgs e)
{
base.OnKeyUp(e);
ShowOnChar(new string(((char)(e.KeyValue)),1));
}
private void ShowOnChar(string C)
{
if (IsPrintChar(C))
{
this.ShowAutoComplete();
}
}
private bool IsPrintChar(int C)
{
return IsPrintChar(((char)(C)));
}
private bool IsPrintChar(byte C)
{
return IsPrintChar(((char)(C)));
}
private bool IsPrintChar(char C)
{
return IsPrintChar(C.ToString());
}
private bool IsPrintChar(string C)
{
if (System.Text.RegularExpressions.Regex.IsMatch(C, "[^\\t\\n\\r\\f\\v]"))
{
return true;
}
else
{
return false;
}
}
private void clsCustomAutoCompleteTextbox_GotFocus(object sender, System.EventArgs e)
{
if ((!this.SuspendFocus
&& (this.myShowAutoCompleteOnFocus
&& (this.myForm.Visible == false))))
{
this.ShowAutoComplete();
}
}
private void clsCustomAutoCompleteTextbox_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (!SelectItem(e.KeyCode, false, false))
{
if ((e.KeyCode == Keys.Up))
{
if ((myLbox.SelectedIndex > 0))
{
MoveLBox((myLbox.SelectedIndex - 1));
}
}
else if ((e.KeyCode == Keys.Down))
{
MoveLBox((myLbox.SelectedIndex + 1));
}
}
}
new void SelectAll()
{
}
private void MoveLBox(int Index)
{
try
{
if ((Index
> (myLbox.Items.Count - 1)))
{
Index = (myLbox.Items.Count - 1);
}
myLbox.SelectedIndex = Index;
}
catch
{
}
}
private void clsCustomAutoCompleteTextbox_Leave(object sender, System.EventArgs e)
{
DoHide(sender, e);
}
private void clsCustomAutoCompleteTextbox_LostFocus(object sender, System.EventArgs e)
{
DoHide(sender, e);
}
private void clsCustomAutoCompleteTextbox_Move(object sender, System.EventArgs e)
{
MoveDrop();
}
private void clsCustomAutoCompleteTextbox_ParentChanged(object sender, System.EventArgs e)
{
if (myParentForm != null) myParentForm.Deactivate -= new EventHandler(myParentForm_Deactivate);
myParentForm = GetParentForm(this);
if (myParentForm != null) myParentForm.Deactivate += new EventHandler(myParentForm_Deactivate);
}
private void HideTimer_Tick(object sender, System.EventArgs e)
{
MoveDrop();
DoHide(sender, e);
Cnt++;
if ((Cnt > 300))
{
if (!AppHasFocus(""))
{
DoHideAuto();
}
Cnt = 0;
}
}
private void myLbox_Click(object sender, System.EventArgs e)
{
}
private void myLbox_DoubleClick(object sender, System.EventArgs e)
{
}
private bool SelectItem(Keys Key, bool SingleClick)
{
return SelectItem(Key, SingleClick, false);
}
private bool SelectItem(Keys Key)
{
return SelectItem(Key, false, false);
}
private bool SelectItem(Keys Key, bool SingleClick, bool DoubleClick)
{
// Warning!!! Optional parameters not supported
// Warning!!! Optional parameters not supported
// Warning!!! Optional parameters not supported
bool DoSelect = true;
SelectOptions Meth = SelectOptions.None;
LastItem = -1;
if (((this.mySelectionMethods & SelectOptions.OnEnterPress) > 0) && (Key == Keys.Enter))
{
Meth = SelectOptions.OnEnterPress;
}
else if (((this.mySelectionMethods & SelectOptions.OnRightArrow) > 0) && Key == Keys.Right)
{
Meth = SelectOptions.OnRightArrow;
}
else if (((this.mySelectionMethods & SelectOptions.OnTabPress) > 0) && Key == Keys.Tab)
{
Meth = SelectOptions.OnTabPress;
}
else if (((this.mySelectionMethods & SelectOptions.OnSingleClick) > 0) && SingleClick)
{
Meth = SelectOptions.OnEnterPress;
}
else if (((this.mySelectionMethods & SelectOptions.OnDoubleClick) > 0) && DoubleClick)
{
Meth = SelectOptions.OnEnterPress;
}
else
{
DoSelect = false;
}
LastItem = myLbox.SelectedIndex;
if (DoSelect)
{
DoSelectItem(Meth);
}
return DoSelect;
}
public class clsItemSelectedEventArgs : EventArgs
{
private int myIndex;
private SelectOptions myMethod;
private string myItemText;
public clsItemSelectedEventArgs()
{
}
public clsItemSelectedEventArgs(int Index, SelectOptions Method, string ItemText)
{
myIndex = Index;
myMethod = Method;
myItemText = ItemText;
}
public string ItemText
{
get
{
return myItemText;
}
set
{
myItemText = value;
}
}
public SelectOptions Method
{
get
{
return myMethod;
}
set
{
myMethod = value;
}
}
public int Index
{
get
{
return myIndex;
}
set
{
myIndex = value;
}
}
}
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern int GetWindowThreadProcessId(IntPtr hWnd, ref int ProcessID);
private bool AppHasFocus(string ExeNameWithoutExtension)
{
bool Out = false;
// Warning!!! Optional parameters not supported
int PID = 0;
if ((ExeNameWithoutExtension == ""))
{
ExeNameWithoutExtension = System.Diagnostics.Process.GetCurrentProcess().ProcessName;
}
IntPtr activeHandle = GetForegroundWindow();
GetWindowThreadProcessId(activeHandle, ref PID);
if ((PID > 0))
{
// For Each p As Process In Process.GetProcessesByName(ExeNameWithoutExtension)
if ((PID == System.Diagnostics.Process.GetCurrentProcess().Id))
{
Out = true;
}
// Next
}
return Out;
}
private void SaveSelects()
{
this.mSelStart = this.SelectionStart;
this.mSelLength = this.SelectionLength;
}
private void LoadSelects()
{
this.SelectionStart = this.mSelStart;
this.SelectionLength = this.mSelLength;
}
private void ShowAutoComplete()
{
Args = new clsAutoCompleteEventArgs();
// With...
Args.Cancel = false;
Args.AutoCompleteList = this.myAutoCompleteList;
if ((myLbox.SelectedIndex == -1))
{
Args.SelectedIndex = 0;
}
else
{
Args.SelectedIndex = myLbox.SelectedIndex;
}
if (BeforeDisplayingAutoComplete != null) BeforeDisplayingAutoComplete(this, Args);
this.myAutoCompleteList = Args.AutoCompleteList;
// If Me.myAutoCompleteList IsNot Nothing AndAlso Me.myAutoCompleteList.Count - 1 < Args.SelectedIndex Then
// Args.SelectedIndex = Me.myAutoCompleteList.Count - 1
// End If
if ((!Args.Cancel && (Args.AutoCompleteList != null) && Args.AutoCompleteList.Count > 0))
{
DoShowAuto();
}
else
{
DoHideAuto();
}
}
private void DoShowAuto()
{
SaveSelects();
myLbox.BeginUpdate();
try
{
myLbox.Items.Clear();
myLbox.Items.AddRange(this.myAutoCompleteList.ToArray());
this.MoveLBox(Args.SelectedIndex);
}
catch (Exception ex)
{
}
myLbox.EndUpdate();
myParentForm = GetParentForm(this);
if (myParentForm != null)
{
myLbox.Name = ("mmmlbox" + DateTime.Now.Millisecond);
if ((myForm.Visible == false))
{
myForm.Font = this.Font;
myLbox.Font = this.Font;
myLbox.Visible = true;
myForm.Visible = false;
myForm.ControlBox = false;
myForm.Text = "";
if (First)
{
myForm.Width = this.Width;
myForm.Height = 200;
}
First = false;
if (!myForm.Controls.Contains(myLbox))
{
myForm.Controls.Add(myLbox);
}
myForm.FormBorderStyle = FormBorderStyle.None;
myForm.ShowInTaskbar = false;
// With...
myLbox.Dock = DockStyle.Fill;
myLbox.SelectionMode = SelectionMode.One;
// Frm.Controls.Add(myLbox)
DontHide = true;
SuspendFocus = true;
myForm.TopMost = true;
myForm.FormBorderStyle = this.myAutoCompleteFormBorder;
myForm.BringToFront();
MoveDrop();
myForm.Visible = true;
myForm.Show();
MoveDrop();
HideTimer.Interval = 10;
this.Focus();
SuspendFocus = false;
HideTimer.Enabled = true;
DontHide = false;
LoadSelects();
}
}
}
void MoveDrop()
{
Point Pnt = new Point(this.Left, (this.Top
+ (this.Height + 2)));
Point ScreenPnt = this.PointToScreen(new Point(-2, this.Height));
// Dim FrmPnt As Point = Frm.PointToClient(ScreenPnt)
if (myForm != null)
{
myForm.Location = ScreenPnt;
// myForm.BringToFront()
// myForm.Focus()
// myLbox.Focus()
// Me.Focus()
}
}
void DoHide(object sender, EventArgs e)
{
HideAuto();
}
private void DFocus(int Delay)
{
// Warning!!! Optional parameters not supported
FocusTimer.Interval = Delay;
FocusTimer.Start();
}
private void DFocus()
{
DFocus(10);
}
private void DoHideAuto()
{
myForm.Hide();
HideTimer.Enabled = false;
FocusTimer.Enabled = false;
}
private void HideAuto()
{
if ((myForm.Visible && HasLostFocus()))
{
DoHideAuto();
}
}
private bool HasLostFocus()
{
bool Out = false;
if (this.myForm == null || myForm.ActiveControl != this.myLbox)
{
Out = true;
}
if (this.myParentForm == null || this.myParentForm.ActiveControl != this)
{
Out = true;
}
return Out;
}
private Form GetParentForm(Control InCon)
{
Control TopCon = FindTopParent(InCon);
Form Out = null;
if ((TopCon is Form))
{
Out = ((Form)(TopCon));
}
return Out;
}
private Control FindTopParent(Control InCon)
{
Control Out;
if ((InCon.Parent == null))
{
Out = InCon;
}
else
{
Out = FindTopParent(InCon.Parent);
}
return Out;
}
private void DoSelectItem(SelectOptions Method)
{
if (((this.myLbox.Items.Count > 0)
&& (this.myLbox.SelectedIndex > -1)))
{
string Value = this.myLbox.SelectedItem.ToString();
string Orig = this.Text;
this.Text = Value;
if (mySelectTextAfterItemSelect)
{
try
{
this.SelectionStart = Orig.Length;
this.SelectionLength = (Value.Length - Orig.Length);
}
catch (Exception ex)
{
}
}
else
{
// Me.SelectionStart = Me.Text.Length
// Me.SelectionLength = 0
}
clsItemSelectedEventArgs a;
a = new clsItemSelectedEventArgs();
a.Index = this.myLbox.SelectedIndex;
a.Method = Method;
a.ItemText = Value;
if (ItemSelected != null) ItemSelected(this, a);
//ItemSelected(this, new clsItemSelectedEventArgs(this.myLbox.SelectedIndex, Method, Value));
this.DoHideAuto();
}
}
private void myLbox_GotFocus(object sender, System.EventArgs e)
{
DFocus();
}
private void myLbox_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
SelectItem(e.KeyCode);
}
private void ProcessKeyEvents(KeyEventArgs e)
{
if ((e.KeyCode >= Keys.A) && (e.KeyCode <= Keys.Z))
base.OnKeyUp(e);
//Keys.Back;
//Keys.Enter;
//Keys.Left;
//Keys.Right;
//Keys.Up;
//Keys.Down;
//(Keys.NumPad0 & (e.KeyCode <= Keys.NumPad9));
//(Keys.D0 & (e.KeyCode <= Keys.D9));
}
private void myLbox_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
if (IsPrintChar(e.KeyChar))
{
// Me.OnKeyPress(e)
// Call MoveDrop()
}
}
private void myLbox_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (IsPrintChar(e.KeyValue))
{
// Me.OnKeyUp(e)
// Call MoveDrop()
}
}
private void myLbox_LostFocus(object sender, System.EventArgs e)
{
DoHide(sender, e);
}
private void myLbox_MouseClick(object sender, System.Windows.Forms.MouseEventArgs e)
{
// If e.Button <> Windows.Forms.MouseButtons.None Then
SelectItem(Keys.None,true);
// End If
}
private void myLbox_MouseDoubleClick(object sender, System.Windows.Forms.MouseEventArgs e)
{
// If e.Button <> Windows.Forms.MouseButtons.None Then
SelectItem(Keys.None, false, true);
// End If
}
private void myForm_Deactivate(object sender, System.EventArgs e)
{
}
private void myParentForm_Deactivate(object sender, System.EventArgs e)
{
}
private void FocusTimer_Tick(object sender, System.EventArgs e)
{
this.Focus();
}
private void myLbox_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
myLbox_MouseClick(sender, e);
}
}
}
I don't know if this is an option, but, for example you could do something like this:
private void Main_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt.Columns.Add("colCustomers", typeof(string));
dt.Rows.Add(new object[] { "1 John" });
dt.Rows.Add(new object[] { "2 Kate" });
dt.Rows.Add(new object[] { "3 Jill" });
comboBox1.DataSource = dt.DefaultView; //allows us to filter the results
comboBox1.DisplayMember = "Col1";
}
private void comboBox1_TextChanged(object sender, EventArgs e)
{
if (comboBox1.SelectedIndex == -1)
{
dt.DefaultView.RowFilter = "colCustomers LIKE '%" + comboBox1.Text + "%'";
}
}
Ofcourse, you can also use searching & positioning instead of filtering, but since there's probably many customers I thought it would be better to leave just the customers that match. When the user deletes his entry it should display everyone again. The code could probably benefit from some tweaking to your needs, but you'll have to experiment to come up with what you wanted.
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