มีปัญหาเรื่องการ Update ข้อมูลในตารางในหน้าแก้ไขข้อมูลส่วนตัวครับ

cus.UserName = "David"

cus.UserName = Me.txtUser.Text.ToString()

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
     
        Dim CurrentUserName As String = ""
        CurrentUserName = Session("UserAuthentication")

        Dim cus = From p In db.Users
                  Where (p.UserUsername.Trim() = CurrentUserName)
        Select p

        For Each m In cus
            txtName.Text = m.UserName
            txtAddress.Text = m.UserAddress
            txtProvince.Text = m.UserProvince
            txtPhone.Text = m.UserPhone
            txtEmail.Text = m.UserEmail
            txtDate.Text = m.UserDate

        Next
        
    End Sub

    Sub Page_Load(sender As Object, e As EventArgs)
		strConnString = "Server=localhost;Uid=sa;PASSWORD=;database=mydatabase;Max Pool Size=400;Connect Timeout=600;"
		objConn.ConnectionString = strConnString
		objConn.Open()

		IF Not Page.IsPostBack() Then
			'*** DataTable ***'
			Dim dtAdapter As SqlDataAdapter 
			Dim dt As New DataTable
			strSQL = "SELECT * FROM customer WHERE CustomerID = '"& Request.QueryString("CustomerID") &"' "	
			dtAdapter = New SqlDataAdapter(strSQL, objConn)
			dtAdapter.Fill(dt)
			
			If dt.Rows.Count > 0 Then
				Me.txtCustomerID.Text = dt.Rows(0)("CustomerID")
				Me.txtName.Text = dt.Rows(0)("Name")
				Me.txtEmail.Text = dt.Rows(0)("Email")
				Me.txtCountryCode.Text = dt.Rows(0)("CountryCode")
				Me.txtBudget.Text = dt.Rows(0)("Budget")
				Me.txtUsed.Text = dt.Rows(0)("Used")
			End IF
		End IF	
    End Sub