asp.net update with datareader don't work - asp.net

Question

i want to change textbox information but when i try to do that it's don't work
this is my asp.net vb code
Imports System.Data.SqlClient
Imports System.Data
Imports System.Data.SqlClient.SqlDataReader
Partial Class _Default
Inherits System.Web.UI.Page
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim connectionString As String = "Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\napster\Documents\ZE.mdf;Integrated Security=True;Connect Timeout=30"
Dim queryString As String = "Update TEST Set chaine1= '" & TextBox1.Text & "' "
Dim connection As New SqlConnection(connectionString)
Dim command As New SqlCommand(queryString, connection)
connection.Open()
command.ExecuteNonQuery()
connection.Close()
End Sub
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
Dim connectionString As String = "Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\napster\Documents\ZE.mdf;Integrated Security=True;Connect Timeout=30"
Dim queryString As String = "SELECT * from TEST "
Dim connection As New SqlConnection(connectionString)
Dim command As New SqlCommand(queryString, connection)
connection.Open()
Dim dataReader As SqlDataReader = command.ExecuteReader()
While dataReader.Read()
TextBox1.Text = dataReader.GetSqlString(3)
End While
TextBox1.
End Sub
End Class

Answer 1

You should always consider how the ASP.NET model works.
In ASP.NET, when you click a button that executes a server side code (the event) you get always a call to the Page.Load event before the call to your event handler code.
In your Page.Load you execute again the code to load the TextBox from the database, but this code destroys the content of the textbox that has been typed by you. The textbox is set to the original value extracted by the database, so, when the code in the button event handler is executed it writes the same value to the database.
To resolve this situation you need to add this to the Page_Load event
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
if Not IsPostBack Then
Dim connectionString As String = "......"
Dim queryString As String = "SELECT * from TEST "
Dim connection As New SqlConnection(connectionString)
Dim command As New SqlCommand(queryString, connection)
connection.Open()
Dim dataReader As SqlDataReader = command.ExecuteReader()
While dataReader.Read()
TextBox1.Text = dataReader.GetSqlString(3)
End While
End If
End Sub
Said that, please take notice, your code in the button click event is very dangerous because you concatenate whatever is typed by the user to a string that is then passed as a sql command to the database. This is the pattern used by the Sql Injection attacks that could destroy your database or stole valuable information from you tables