Imports System.Data
Imports System.Data.SqlClient
Imports System.Threading
Imports System.Text.RegularExpressions
Imports System.Text

Public Class Form1

    Dim da As SqlDataAdapter
    Dim conn As SqlConnection
    'Dim conn1 As SqlConnection
    Dim ds As DataSet
    Dim sql As String
    Dim MaxRows As Integer


    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Dim myCommand As New SqlCommand(sql, conn)

        Dim connectionString As String = "Data Source=itcu-23\sqlexpress;Initial Catalog=compare;" & "Integrated Security=SSPI;"
        conn = New SqlConnection(connectionString)

        sql = "SELECT * FROM  CustDetail"


        da = New SqlDataAdapter(sql, conn)
        ds = New DataSet()
        Dim commandBuilder As SqlCommandBuilder = New SqlCommandBuilder(da)

        da.FillSchema(ds, SchemaType.Mapped)
        da.Fill(ds, "CustDetail")


        MaxRows = ds.Tables("CustDetail").Rows.Count
        MaxRows = MaxRows - 1


       'Dim Number As New List(Of String)
        Dim Words() As String = New String() _
      { ds.Tables("CustDetail").Columns(3)}
        Number.AddRange(Words)
        Number.Sort()
        ComboBox1.Items.AddRange(Number.ToArray)
        ComboBox1.DropDownStyle = ComboBoxStyle.DropDownList
        ComboBox1.AutoCompleteSource = AutoCompleteSource.ListItems
        ComboBox1.SelectedIndex = 0

    End Sub
End Class

//Set the auto complete mode to enable auto complete.
this.textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
//The data source is filled programmatically.
this.textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
//Create the custom source.
this.textBox1.AutoCompleteCustomSource = new AutoCompleteStringCollection();
//Get the DataTable.
DataTable dt = GetData();
//The column we want to help the input.
const int suggestColumnIndex = 0;
//Traverse the rows and and the suggest values.
foreach (DataRow row in dt.Rows)
{
    this.textBox1.AutoCompleteCustomSource.Add(row[suggestColumnIndex].ToString());
}

        '//Set the auto complete mode to enable auto complete.
        Me.TextBox1.AutoCompleteMode = AutoCompleteMode.Suggest
        '//The data source is filled programmatically.
        Me.TextBox1.AutoCompleteSource = AutoCompleteSource.CustomSource
        '//Create the custom source.
        Me.TextBox1.AutoCompleteCustomSource = New AutoCompleteStringCollection()

        MaxRows = ds.Tables("CustDetail").Rows.Count
        MaxRows = MaxRows - 1
        Dim numbers() As Integer
        Dim EndAt As Integer
        inc = 0
        MsgBox(MaxRows)
        EndAt = MaxRows
        ReDim numbers(EndAt)

        For i = inc To EndAt

            Me.TextBox1.AutoCompleteCustomSource.Add(ds.Tables("CustDetail").Columns(3).ToString())


        Next i

                    Dim nameCommand As SqlCommand = conn.CreateCommand()
                    nameCommand.CommandText = _
                   "DELETE FROM CustDetail WHERE RmuNum = '" & txtSearch.Text & "'"

                    nameCommand.ExecuteNonQuery()

                    da.Update(ds, "CustDetail")

                    Me.txtSearch.AutoCompleteCustomSource.Clear()

                    Me.txtSearch.AutoCompleteMode = AutoCompleteMode.Suggest
                    'The data source is filled programmatically. 
                    Me.txtSearch.AutoCompleteSource = AutoCompleteSource.CustomSource
                    'Create the custom source. 
                    Me.txtSearch.AutoCompleteCustomSource = New AutoCompleteStringCollection()
                    'Get the DataTable. 
                    dt = ds.Tables("CustDetail")
                    'The column we want to help the input. 
                    Const suggestColumnIndex As Integer = 3
                    'Traverse the rows and and the suggest values. 
                    For Each row As DataRow In dt.Rows
                        Me.txtSearch.AutoCompleteCustomSource.Add(row(suggestColumnIndex).ToString())
                    Next