retrieving data from SQL in VB (part 2)

后端 未结 3 858
难免孤独
难免孤独 2021-01-14 13:24

I am trying to populate a listbox by retrieving data from a database through sql. I have asked this question earlier but i was using a different configuration and the one i\

3条回答
  •  傲寒
    傲寒 (楼主)
    2021-01-14 13:35

    You missed the connectionString
    If you want to populate list from DB there are many ways

    With DataReader

    Imports System.Data.Sql
    Imports System.Data.SqlClient
    
    
    Public Class Form1
    
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim connectionString As String = "Data Sourec=localhost;........."
        Dim conn As New SqlConnection(connectionString)
        conn.Open()
        Dim comm As New SqlCommand("SELECT name FROM Table_1", conn)
        Dim reader As SqlDataReader = comm.ExecuteReader
        /* As it is not working i commented this
        listBox1.ItemsSource = dt; // use this instead of  ListBox1.Items.Add(dt)
        //because Add event add only one item in the list. 
         */
        Dim i As Integer
        i=0
        while reader.read() 
        listbox1.Items.Add(dr(i).ToString);
        i++
        End While
    
     End Sub
    End Class
    

    With DataTable

    Imports System.Data.Sql
    Imports System.Data.SqlClient
    
    
    Public Class Form1
    
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim connectionString As String = "Data Sourec=localhost;........."
        Dim conn As New SqlConnection(connectionString)
        conn.Open()
        // Create new DataAdapter
        SqlDataAdapter a = new SqlDataAdapter("SELECT * FROM EmployeeIDs", c)
        // Use DataAdapter to fill DataTable
        DataTable dt = new DataTable();
        a.Fill(dt);
        ListBox1.DataSource = dt;
        ListBox1.DataTextField = "name";
    
    
    
     End Sub
    End Class
    


    EDIT:
    Other parameters of connection string depends on your security and all that. You must see this link Connection strings for SQL Server 2008

提交回复
热议问题