Develop Reference

How can I make an image appear in Windows Forms C# when a specific value in ComboBox is selected?

I am trying to make a drop down list with several options ( educational majors ) and when the user selects a specific value ( educational major ) a study plan of that Major appears.
I already did the drop down list as follows:
InitializeComponent();
string i = "Information Technology";
string m = "Medical Lap";
comboBox1.Items.Add(i);
comboBox1.Items.Add(m);
comboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
And now remains the process when a value is selected an image related to that value appears.

Based on your description, you want to show the correspond image when you select an item from combobox.
I suggest that you can use Dictionary to do it.
Here is a code example you can refer to.
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
foreach (var item in dic)
{
if(item.Key==comboBox1.SelectedItem.ToString())
{
pictureBox1.Image = item.Value;
}
}
}
Dictionary<string, Image> dic = new Dictionary<string, Image>();
private void Form1_Load(object sender, EventArgs e)
{
dic.Add("Information", Image.FromFile("D:\\1.jpg"));
dic.Add("Medical", Image.FromFile("D:\\2.jpg"));
dic.Add("Political", Image.FromFile("D:\\3.jpg"));
dic.Add("biological", Image.FromFile("D:\\4.jpg"));
foreach (var item in dic)
{
comboBox1.Items.Add(item.Key);
}
comboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
}
The result:

You will need to create an event handler that subscribes to the SelectedIndexChanged event of the combobox and inside of that event handler write the code that will display the proper image.
https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.combobox.selectedindexchanged?view=netcore-3.1

if you created the combobox using VS once you double click on it creates the event handler for you , and attach it to the control, however if you need to add that manually you will need to do that in the initialize function see below
public Form1()
{
InitializeComponent();
}
private void InitializeComponent()
{
this.comboBox1 = new System.Windows.Forms.ComboBox();
this.SuspendLayout();
//
// comboBox1
//
this.comboBox1.FormattingEnabled = true;
this.comboBox1.Location = new System.Drawing.Point(174, 68);
this.comboBox1.Name = "comboBox1";
this.comboBox1.Size = new System.Drawing.Size(121, 21);
this.comboBox1.TabIndex = 0;
this.comboBox1.SelectedIndexChanged += new
***System.EventHandler(this.comboBox1_SelectedIndexChanged);***
}
Properties of the Combobox to assign event handler
after that you need to insert the code that will define the source of the picture box
example
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
string picturelocation = "";
picturelocation =#"c:\images\" + comboBox1.Text + ".jpg" ;
pictureBox1.ImageLocation = picturelocation;
}
where the combobox1.text will be your file names

Binding dynamic datalist in C#

I am trying to create a dynamic Data List bind with database. I can easily create this but I am not able to make the item Command of this Data List. Please help me. Here is my code below
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
categorybinding();
}
}
public void categorybinding()
{
int totalcate = (from x in ebooks.books_category select x).Count();
var ra = (from x in ebooks.books_category select x);
DataList dl = new DataList();
dl.ItemTemplate = new DatalistLabelColumnBind();
dl.DataSource = ra;
dl.DataBind();
form1.Controls.Add(dl);
dl.ItemCommand += new DataListCommandEventHandler(this.ItemCommandHandler);
}
public void ItemCommandHandler(object sender, DataListCommandEventArgs e)
{
Response.Redirect("NewPage.aspx?"+e.CommandArgument.ToString());
}
//Create a new class implementing ITemplate
public class DatalistLabelColumnBind : ITemplate
{
public DatalistLabelColumnBind()
{
//Add constructor
}
public void InstantiateIn(Control container)
{
LinkButton label1 = new LinkButton();
label1.DataBinding += new EventHandler(this.BindLabelColumn);
container.Controls.Add(label1);
}
public void BindLabelColumn(object sender, EventArgs e)
{
LinkButton lbl = (LinkButton)sender;
DataListItem container = (DataListItem)lbl.NamingContainer ;
String strVals = Convert.ToString(DataBinder.Eval(((DataListItem)container).DataItem, "books_category1"));
lbl.CommandArgument = Convert.ToString(DataBinder.Eval(((DataListItem)container).DataItem, "id_books"));
lbl.Text = strVals;
}
}
My Problem :
My Data List easily added on the page but when I click on the Link Button which is added in the Data List is does not Redirect to the NewPage.aspx
Help me out..

I think your Response.Redirect is not resolving to the intended page.
Try:
Response.Redirect("~/NewPage.aspx?"+e.CommandArgument.ToString());

Write categorybinding() function after the if condition in Page_Load. And ItemCommandHandler will definitely work.

Trying to grab information from a Data Table in Form 2 and set Textboxes in Form 1 using C#

I have two forms (Form 1 and Form 2), I am successful in passing a data table from Form 1 to Form 2 by filling a data grid view in a dialog box. I also have an event handler to capture double click events on a selected row. When the event occurs I want to set textboxes in form 1 from the click event in form 2. No matter what I try I can not seem to show the text inside the textboxes. Below is my code:
//Code begins here
//....Function to fill data table from form 1 and pass to form 2
private void buttonNewEntryLookUp_Click(object sender, EventArgs e)
{
try
{
cs.Open();
da.SelectCommand = new SqlCommand("Select ctx_customername AS Customer, ctx_contactname AS Contact, ctx_custaddress1 AS Address, ctx_custcity AS City, ctx_custstate AS State, nno_custzip AS ZIP, ctx_custemail AS Email FROM Customers WHERE nno_custphone = '" + maskedTextBoxNewLogTel.Text + "'", cs);
dt.Clear();
da.Fill(dt);
}
catch
{
MessageBox.Show("Connection to Database could not be established, please close this application and try again. If problem continues please contact server Admin. Thank you.", "AAMP");
//Display this message if connection could not be made
}
cs.Close();//close connection to db
if (dt.Rows.Count == 0)//if there are no returned results then this must be a new entry into the database
{
MessageBox.Show("Phone Number Not Found in Database.", "AAMP");
}
else//number was found
{
Form2 form2 = new Form2(dt);//create object of form 2 and pass the data table.
form2.ShowDialog();//show form 2 with data table in the grid view.
}
}
public void getContactInfo(string[] contactInfo)
{
textBoxNewLogCustomerName.Text = contactInfo[0];
textBoxNewLogContactName.Text = contactInfo[1];
textBoxNewLogAddress.Text = contactInfo[2];
textBoxNewLogCity.Text = contactInfo[3];
textBoxNewLogState.Text = contactInfo[4];
textBoxNewLogZIP.Text = contactInfo[5];
textBoxNewLogEmail.Text = contactInfo[6];
}
//code for form 2
public partial class Form2 : Form
{
/*Globals for Form 2*/
DataTable g_dt;
public Form2(DataTable dt)
{
InitializeComponent();
dataGridViewLookUp.DataSource = dt;
g_dt = dt;
}
private void dataGridViewLookUp_RowHeaderMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
{
Form1 form1 = new Form1();
string[] contactInfo = new string[7];
contactInfo[0] = Convert.ToString(g_dt.Rows[e.RowIndex]["Customer"]);
contactInfo[1] = Convert.ToString(g_dt.Rows[e.RowIndex]["Contact"]);
contactInfo[2] = Convert.ToString(g_dt.Rows[e.RowIndex]["Address"]);
contactInfo[3] = Convert.ToString(g_dt.Rows[e.RowIndex]["City"]);
contactInfo[4] = Convert.ToString(g_dt.Rows[e.RowIndex]["State"]);
contactInfo[5] = Convert.ToString(g_dt.Rows[e.RowIndex]["ZIP"]);
contactInfo[6] = Convert.ToString(g_dt.Rows[e.RowIndex]["Email"]);
form1.getContactInfo(contactInfo);//return the row number being clicked.
this.Close();
}
}
I am successful in passing the data table to form 2 and capturing the correct information to fill the string array but when I pass the string array back by calling the getContactInfo function I can not seem to set my textboxes with the data. Can someone please, please help!
Thanks.

Your OP is a little vague, but I have some code that does this, takes some data in form 2 and sends it back to form 1.
Here's the code from form1:
private void btnGroupNameLookup_Click(object sender, EventArgs e)
{
//instantiate an instance of the grp name lookup form
frmGroupNameLookup lookupName = new frmGroupNameLookup();
//add an event handler to update THIS form when the lookup
//form is updated. (This is when LookupUpdated fires
lookupName.GroupNamesFound += new frmGroupNameLookup.LookupHandler(lookupName_GroupNamesFound);
//rc.ReconCFUpdated += new ReconCaseFileChecklist.ReconCFListHandler(ReconCFForm_ButtonClicked);
lookupName.Show();
}
void lookupName_GroupNamesFound(object sender, GroupNameLookupUpdateEventArgs e)
{
//update the list boxes here
foreach (string s in e.Parents)
{
lstFilteredGroupParents.Items.Add(s);
}
foreach (string s in e.Groups)
{
lstFilteredGroups.Items.Add(s);
//link supgroups and plan ids
GetFilteredSubgroupNos(s);
GetFilteredPlanIds(s);
}
//ensure dupes are stripped out
//filter out duplicates
var noDupeSubgroups = subgroupList.Distinct().ToList();
noDupeSubgroups.Sort();
foreach (string s in noDupeSubgroups)
{
lstFilteredSubgroups.Items.Add(s);
}
var noDupePlanIDs = planIDList.Distinct().ToList();
noDupePlanIDs.Sort();
foreach (string s in noDupePlanIDs)
{
lstFilteredPlanID.Items.Add(s);
}
}
From Form2
public partial class frmGroupNameLookup : Form
{
//add a delegate, the GroupNameLookupUpdateEventArgs class is defined at the bottom
//of this file
public delegate void LookupHandler(object sender, GroupNameLookupUpdateEventArgs e);
//add an event of the delegate type
public event LookupHandler GroupNamesFound;
//this event closes the forms and passes 2 lists back to form 1
private void btnCommit_Click(object sender, EventArgs e)
{
List<string> prnt = new List<string>();
List<string> grp = new List<string>();
//get selected rows
if (grdLookup.SelectedRows.Count > 0)
{
foreach (DataGridViewRow row in grdLookup.SelectedRows)
{
prnt.Add(row.Cells[0].Value.ToString());
grp.Add(row.Cells[1].Value.ToString());
}
//filter out duplicates
var noDupeParentGroups = prnt.Distinct().ToList();
noDupeParentGroups.Sort();
// instance the event args and pass it each value
GroupNameLookupUpdateEventArgs args =
new GroupNameLookupUpdateEventArgs(noDupeParentGroups, grp);
// raise the event with the updated arguments
this.GroupNamesFound(this, args);
this.Dispose();
}
}
}
public class GroupNameLookupUpdateEventArgs : System.EventArgs
{
// add local member variables to hold text
private List<string> mParents = new List<string>();
private List<string> mGroups = new List<string>();
// class constructor
public GroupNameLookupUpdateEventArgs(List<string> sParents, List<string> sGroups)
{
this.mParents = sParents;
this.mGroups = sGroups;
}
// Properties - Viewable by each listener
public List<string> Parents
{
get { return mParents; }
}
public List<string> Groups
{
get { return mGroups; }
}
}

Simple. Make the contact information a method public in Form2 and then just assign it after the ShowDialog() in form1.
else//number was found
{
Form2 form2 = new Form2(dt);//create object of form 2 and pass the data table.
form2.ShowDialog();//show form 2 with data table in the grid view.
getContactInfo(form2.ContactInfoFromForm2);
}

You're passing the datatable into the constructor of Form2:
Form2 form2 = new Form2(dt);
You could instead pass a reference to the entire Form1:
Form2 form2 = new Form2(this);
Then you make public methods on Form1 that Form2 can use to update data. Something like this:
//In Form1
public DataTable getDataTable(){
//return datatable
}
public void setTextBoxValue(string Value){
//Set the value
}
And then in Form2
private Form1 _form1;
public Form2(Form1 form1){
_form1 = form1;
dataGridViewLookUp.DataSource = _form1.getDataTable();
g_dt = dt;
}
private void dataGridViewLookUp_RowHeaderMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
{
_form1.setTextBoxValue(Convert.ToString(g_dt.Rows[e.RowIndex]["Customer"]));
//etc
}

Are you getting an error or is the data just not displaying. Maybe try a ToString() method behind each stringarray index in the getcontactinfo method. (i.e. contactInfo[0].ToString();)

How to add item to Repeater control manually

First of all:
_ddlOptions is drop down list
_selectedOptions is repeater control
and it's just provisional code of my final control.
What I want to do is to get data for _ddlOption on !IsPostBack. There is Add button that enables user to move selected drop down item to repeater control.
It the following way of updating Repeater.Items correct? I found many solution of adding/removing elements manually using DataSource, but here my DataSource is null, as I set it only on !IsPostBack.
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
_ddlOptions.DataSource = new[] { 1, 2, 3 };
_ddlOptions.DataBind();
}
}
protected void OnAdd(object sender, EventArgs e)
{
var list = new ArrayList(_selectedOptions.Items);
list.Add(_ddlOptions.SelectedItem);
_ddlOptions.Items.RemoveAt(_ddlOptions.SelectedIndex);
_selectedOptions.DataSource = list;
_selectedOptions.DataBind();
}

If you only need to fetch data once and you're going to use viewstate, get the data first time you need it, store it in VS and get it from VS for all future PostBacks.
Example:
public List<int> Data
{
get
{
if (ViewState["Data"] == null)
{
// Get your data, save it and return it.
var data = new List<int> { 1, 2, 3 };
ViewState["Data"] = data;
return data;
}
return (List<int>)ViewState["Data"];
}
set
{
ViewState["Data"] = value;
}
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindData(Data);
}
}
private void BindData(List<int> data)
{
_ddlOptions.DataSource = data;
_ddlOptions.DataBind();
}
protected void OnAdd(object sender, EventArgs e)
{
var existing = Data;
existing.Add(_ddlOptions.SelectedItem);
_ddlOptions.Items.RemoveAt(_ddlOptions.SelectedIndex);
Data = existing;
BindData(existing);
}
I didn't test this - and its only my first thought but you can build on it from here.
Patrick.

Looks good to me. You just may want to move the decalration for your list outside the onAdd method. As you have it I think it will be reinitialized every time the add button is clicked, so you'll never have more than the currently selected item in your repeater.

You can use a DataAdapter to fill a table in a DataSet.
DataSet ds = new DataSet();
using (SqlConnection conn = YourConnectionFactory.GetConnection())
{
SqlCommand objComm = DBHelper.CreateStoredProc("YourStoredProcedure",
conn);
SqlDataAdapter adapt = new SqlDataAdapter(objComm);
adapt.Fill(ds, TableName);
conn.Close();
}
DataTable dt = ds.Tables[0];
for (int a=dt.Rows.Count-1; a>= 0; a--)
{
// check and insert as necessary
}
YourControl.DataSource = ds;
YourControl.DataBind();
You can also do something like this then,
like rebind Taken from: http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.repeater.aspx:
Dim values As New ArrayList()
values.Add(New PositionData("Microsoft", "Msft"))
values.Add(New PositionData("Intel", "Intc"))
values.Add(New PositionData("Dell", "Dell"))
Repeater1.DataSource = values Repeater1.DataBind()
Repeater2.DataSource = values Repeater2.DataBind()

Winforms ComboBox autocomplete search multiple parts of string [duplicate]

I am trying to add an autocomplete feature to a textbox, the results are coming from a database. They come in the format of
[001] Last, First Middle
Currently you must type [001]... to get the entries to show. So the problem is that I want it to complete even if I type the firstname first. So if an entry was
[001] Smith, John D
if I started typing John then this entry should show up in the results for the auto complete.
Currently the code looks something like
AutoCompleteStringCollection acsc = new AutoCompleteStringCollection();
txtBox1.AutoCompleteCustomSource = acsc;
txtBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
txtBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
....
if (results.Rows.Count > 0)
for (int i = 0; i < results.Rows.Count && i < 10; i++)
{
row = results.Rows[i];
acsc.Add(row["Details"].ToString());
}
}
results is a dataset containing the query results
The query is a simple search query using the like statement. The correct results are returned if we do not use the autocomplete and just toss the results into an array.
Any advice?
EDIT:
Here is the query that returns the results
SELECT Name from view_customers where Details LIKE '{0}'
With {0} being the placeholder for the searched string.

The existing AutoComplete functionality only supports searching by prefix. There doesn't seem to be any decent way to override the behavior.
Some people have implemented their own autocomplete functions by overriding the OnTextChanged event. That's probably your best bet.
For example, you can add a ListBox just below the TextBox and set its default visibility to false. Then you can use the OnTextChanged event of the TextBox and the SelectedIndexChanged event of the ListBox to display and select items.
This seems to work pretty well as a rudimentary example:
public Form1()
{
InitializeComponent();
acsc = new AutoCompleteStringCollection();
textBox1.AutoCompleteCustomSource = acsc;
textBox1.AutoCompleteMode = AutoCompleteMode.None;
textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
}
private void button1_Click(object sender, EventArgs e)
{
acsc.Add("[001] some kind of item");
acsc.Add("[002] some other item");
acsc.Add("[003] an orange");
acsc.Add("[004] i like pickles");
}
void textBox1_TextChanged(object sender, System.EventArgs e)
{
listBox1.Items.Clear();
if (textBox1.Text.Length == 0)
{
hideResults();
return;
}
foreach (String s in textBox1.AutoCompleteCustomSource)
{
if (s.Contains(textBox1.Text))
{
Console.WriteLine("Found text in: " + s);
listBox1.Items.Add(s);
listBox1.Visible = true;
}
}
}
void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{
textBox1.Text = listBox1.Items[listBox1.SelectedIndex].ToString();
hideResults();
}
void listBox1_LostFocus(object sender, System.EventArgs e)
{
hideResults();
}
void hideResults()
{
listBox1.Visible = false;
}
There's a lot more you could do without too much effort: append text to the text box, capture additional keyboard commands, and so forth.

If you decide to use a query that is based on user input make sure you use SqlParameters to avoid SQL Injection attacks
SqlCommand sqlCommand = new SqlCommand();
sqlCommand.CommandText = "SELECT Name from view_customers where Details LIKE '%" + #SearchParam + "%'";
sqlCommand.Parameters.AddWithValue("#SearchParam", searchParam);

Here's an implementation that inherits the ComboBox control class, rather than replacing the whole combo-box with a new control. It displays its own drop-down when you type in the text box, but clicking to show the drop-list is handled as before (i.e. not with this code). As such you get that proper native control and look.
Please use it, modify it and edit the answer if you would like to improve it!
class ComboListMatcher : ComboBox, IMessageFilter
{
private Control ComboParentForm; // Or use type "Form"
private ListBox listBoxChild;
private int IgnoreTextChange;
private bool MsgFilterActive = false;
public ComboListMatcher()
{
// Set up all the events we need to handle
TextChanged += ComboListMatcher_TextChanged;
SelectionChangeCommitted += ComboListMatcher_SelectionChangeCommitted;
LostFocus += ComboListMatcher_LostFocus;
MouseDown += ComboListMatcher_MouseDown;
HandleDestroyed += ComboListMatcher_HandleDestroyed;
}
void ComboListMatcher_HandleDestroyed(object sender, EventArgs e)
{
if (MsgFilterActive)
Application.RemoveMessageFilter(this);
}
~ComboListMatcher()
{
}
private void ComboListMatcher_MouseDown(object sender, MouseEventArgs e)
{
HideTheList();
}
void ComboListMatcher_LostFocus(object sender, EventArgs e)
{
if (listBoxChild != null && !listBoxChild.Focused)
HideTheList();
}
void ComboListMatcher_SelectionChangeCommitted(object sender, EventArgs e)
{
IgnoreTextChange++;
}
void InitListControl()
{
if (listBoxChild == null)
{
// Find parent - or keep going up until you find the parent form
ComboParentForm = this.Parent;
if (ComboParentForm != null)
{
// Setup a messaage filter so we can listen to the keyboard
if (!MsgFilterActive)
{
Application.AddMessageFilter(this);
MsgFilterActive = true;
}
listBoxChild = listBoxChild = new ListBox();
listBoxChild.Visible = false;
listBoxChild.Click += listBox1_Click;
ComboParentForm.Controls.Add(listBoxChild);
ComboParentForm.Controls.SetChildIndex(listBoxChild, 0); // Put it at the front
}
}
}
void ComboListMatcher_TextChanged(object sender, EventArgs e)
{
if (IgnoreTextChange > 0)
{
IgnoreTextChange = 0;
return;
}
InitListControl();
if (listBoxChild == null)
return;
string SearchText = this.Text;
listBoxChild.Items.Clear();
// Don't show the list when nothing has been typed
if (!string.IsNullOrEmpty(SearchText))
{
foreach (string Item in this.Items)
{
if (Item != null && Item.Contains(SearchText, StringComparison.CurrentCultureIgnoreCase))
listBoxChild.Items.Add(Item);
}
}
if (listBoxChild.Items.Count > 0)
{
Point PutItHere = new Point(this.Left, this.Bottom);
Control TheControlToMove = this;
PutItHere = this.Parent.PointToScreen(PutItHere);
TheControlToMove = listBoxChild;
PutItHere = ComboParentForm.PointToClient(PutItHere);
TheControlToMove.Show();
TheControlToMove.Left = PutItHere.X;
TheControlToMove.Top = PutItHere.Y;
TheControlToMove.Width = this.Width;
int TotalItemHeight = listBoxChild.ItemHeight * (listBoxChild.Items.Count + 1);
TheControlToMove.Height = Math.Min(ComboParentForm.ClientSize.Height - TheControlToMove.Top, TotalItemHeight);
}
else
HideTheList();
}
/// <summary>
/// Copy the selection from the list-box into the combo box
/// </summary>
private void CopySelection()
{
if (listBoxChild.SelectedItem != null)
{
this.SelectedItem = listBoxChild.SelectedItem;
HideTheList();
this.SelectAll();
}
}
private void listBox1_Click(object sender, EventArgs e)
{
var ThisList = sender as ListBox;
if (ThisList != null)
{
// Copy selection to the combo box
CopySelection();
}
}
private void HideTheList()
{
if (listBoxChild != null)
listBoxChild.Hide();
}
public bool PreFilterMessage(ref Message m)
{
if (m.Msg == 0x201) // Mouse click: WM_LBUTTONDOWN
{
var Pos = new Point((int)(m.LParam.ToInt32() & 0xFFFF), (int)(m.LParam.ToInt32() >> 16));
var Ctrl = Control.FromHandle(m.HWnd);
if (Ctrl != null)
{
// Convert the point into our parent control's coordinates ...
Pos = ComboParentForm.PointToClient(Ctrl.PointToScreen(Pos));
// ... because we need to hide the list if user clicks on something other than the list-box
if (ComboParentForm != null)
{
if (listBoxChild != null &&
(Pos.X < listBoxChild.Left || Pos.X > listBoxChild.Right || Pos.Y < listBoxChild.Top || Pos.Y > listBoxChild.Bottom))
{
this.HideTheList();
}
}
}
}
else if (m.Msg == 0x100) // WM_KEYDOWN
{
if (listBoxChild != null && listBoxChild.Visible)
{
switch (m.WParam.ToInt32())
{
case 0x1B: // Escape key
this.HideTheList();
return true;
case 0x26: // up key
case 0x28: // right key
// Change selection
int NewIx = listBoxChild.SelectedIndex + ((m.WParam.ToInt32() == 0x26) ? -1 : 1);
// Keep the index valid!
if (NewIx >= 0 && NewIx < listBoxChild.Items.Count)
listBoxChild.SelectedIndex = NewIx;
return true;
case 0x0D: // return (use the currently selected item)
CopySelection();
return true;
}
}
}
return false;
}
}

THIS WILL GIVE YOU THE AUTOCOMPLETE BEHAVIOR YOU ARE LOOKING FOR.
The attached example is a complete working form, Just needs your data source, and bound column names.
using System;
using System.Data;
using System.Windows.Forms;
public partial class frmTestAutocomplete : Form
{
private DataTable maoCompleteList; //the data table from your data source
private string msDisplayCol = "name"; //displayed text
private string msIDcol = "id"; //ID or primary key
public frmTestAutocomplete(DataTable aoCompleteList, string sDisplayCol, string sIDcol)
{
InitializeComponent();
maoCompleteList = aoCompleteList
maoCompleteList.CaseSensitive = false; //turn off case sensitivity for searching
msDisplayCol = sDisplayCol;
msIDcol = sIDcol;
}
private void frmTestAutocomplete_Load(object sender, EventArgs e)
{
testCombo.DisplayMember = msDisplayCol;
testCombo.ValueMember = msIDcol;
testCombo.DataSource = maoCompleteList;
testCombo.SelectedIndexChanged += testCombo_SelectedIndexChanged;
testCombo.KeyUp += testCombo_KeyUp;
}
private void testCombo_KeyUp(object sender, KeyEventArgs e)
{
//use keyUp event, as text changed traps too many other evengts.
ComboBox oBox = (ComboBox)sender;
string sBoxText = oBox.Text;
DataRow[] oFilteredRows = maoCompleteList.Select(MC_DISPLAY_COL + " Like '%" + sBoxText + "%'");
DataTable oFilteredDT = oFilteredRows.Length > 0
? oFilteredRows.CopyToDataTable()
: maoCompleteList;
//NOW THAT WE HAVE OUR FILTERED LIST, WE NEED TO RE-BIND IT WIHOUT CHANGING THE TEXT IN THE ComboBox.
//1).UNREGISTER THE SELECTED EVENT BEFORE RE-BINDING, b/c IT TRIGGERS ON BIND.
testCombo.SelectedIndexChanged -= testCombo_SelectedIndexChanged; //don't select on typing.
oBox.DataSource = oFilteredDT; //2).rebind to filtered list.
testCombo.SelectedIndexChanged += testCombo_SelectedIndexChanged;
//3).show the user the new filtered list.
oBox.DroppedDown = true; //do this before repainting the text, as it changes the dropdown text.
//4).binding data source erases text, so now we need to put the user's text back,
oBox.Text = sBoxText;
oBox.SelectionStart = sBoxText.Length; //5). need to put the user's cursor back where it was.
}
private void testCombo_SelectedIndexChanged(object sender, EventArgs e)
{
ComboBox oBox = (ComboBox)sender;
if (oBox.SelectedValue != null)
{
MessageBox.Show(string.Format(#"Item #{0} was selected.", oBox.SelectedValue));
}
}
}
//=====================================================================================================
// code from frmTestAutocomplete.Designer.cs
//=====================================================================================================
partial class frmTestAutocomplete
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.testCombo = new System.Windows.Forms.ComboBox();
this.SuspendLayout();
//
// testCombo
//
this.testCombo.FormattingEnabled = true;
this.testCombo.Location = new System.Drawing.Point(27, 51);
this.testCombo.Name = "testCombo";
this.testCombo.Size = new System.Drawing.Size(224, 21);
this.testCombo.TabIndex = 0;
//
// frmTestAutocomplete
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(292, 273);
this.Controls.Add(this.testCombo);
this.Name = "frmTestAutocomplete";
this.Text = "frmTestAutocomplete";
this.Load += new System.EventHandler(this.frmTestAutocomplete_Load);
this.ResumeLayout(false);
}
#endregion
private System.Windows.Forms.ComboBox testCombo;
}

If you're running that query (with {0} being replaced by the string entered), you might need:
SELECT Name from view_customers where Details LIKE '%{0}%'
LIKE still needs the % character... And yes, you should use parameters rather than trusting the user's input :)
Also, you seem to be returning the Name column, but querying on the Details column. So if someone types in "John Smith", if that's not in the Details column you won't get what you want back.

Two methods were successful in the autoComplete textBox control with SQL:
but you should do the following:
a- create new project
b- add Component class to project and delete component1.designer "according to the name you give to component class"
c- download "Download sample - 144.82 KB"
and open it and open AutoCompleteTextbox class from AutoCompleteTextbox.cs
d- select all as illustrated in the image and copy it to current component class
http://i.stack.imgur.com/oSqCa.png
e- Final - run project and stop to view new AutoCompleteTextbox in toolBox.
Now you can add the following two method that you can use SQL with them
1- in Form_Load
private void Form1_Load(object sender, EventArgs e)
{
SqlConnection cn = new SqlConnection(#"server=.;database=My_dataBase;integrated security=true");
SqlDataAdapter da = new SqlDataAdapter(#"SELECT [MyColumn] FROM [my_table]", cn);
DataTable dt = new DataTable();
da.Fill(dt);
List<string> myList = new List<string>();
foreach (DataRow row in dt.Rows)
{
myList.Add((string)row[0]);
}
autoCompleteTextbox1.AutoCompleteList = myList;
}
2- in TextChanged Event
private void autoCompleteTextbox_TextChanged(object sender, EventArgs e)
{
SqlConnection cn = new SqlConnection(#"server=.;database=My_dataBase;integrated security=true");
SqlDataAdapter da = new SqlDataAdapter(#"SELECT [MyColumn] FROM [my_table]", cn);
DataTable dt = new DataTable();
da.Fill(dt);
List<string> myList = new List<string>();
foreach (DataRow row in dt.Rows)
{
myList.Add((string)row[0]);
}
autoCompleteTextbox2.AutoCompleteList = myList;
}