![]() |
| ||
| Error message when passing property changes between forms I am working on a login password. I want my front page to load and then the password form to appear. The user then types in userid and password - if correct the login form closes. I want the front page to remain visible behind the login form BUT - I dont want the user to be able to use any buttons on the Front Page until after login is complete. I have the Front Page Enabled = False at Load. I want it to go to Enable = True after Login is complete. I want to pass the change in Enable from my login form to my front page form. (can it be done?) I am getting an error (I have tried using .focus and get the same error ) An unhandled exception of type 'System.NullReferenceException' occurred in WindowsApplication1.exe Additional information: Object reference not set to an instance of an object. (*** = where error is occuring) login form Public Class frmMgtLogin Inherits System.Windows.Forms.Form Dim UP As New OleDb.OleDbCommand Dim Con As New OleDb.OleDbConnection Dim Read As OleDb.OleDbDataReader Dim Plus As Integer Public CurrentForm As System.Windows.Forms.Form Private Sub btnSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubmit.Click If txtUserName.Text.Trim = "" Then MessageBox.Show("Please fill your User Name !", _ "Password", MessageBoxButtons.OK, _ MessageBoxIcon.Exclamation) txtUserName.Focus() Exit Sub End If 'if textbox2 is blank then ... If txtPassword.Text.Trim = "" Then MessageBox.Show("Please fill your Password !", _ "Password", MessageBoxButtons.OK, _ MessageBoxIcon.Exclamation) txtPassword.Focus() Exit Sub End If 'Admin UP.Parameters.Add("user", Data.OleDb.OleDbType.Variant) UP.Parameters.Add("password", Data.OleDb.OleDbType.Variant) UP.Parameters("user").Value = txtUserName.Text UP.Parameters("password").Value = txtPassword.Text 'Open database connection Con.Open() ' Read information from database Read = UP.ExecuteReader ar() ' Close database connection Con.Close() End Sub Private Sub ar() With Read If .Read Then Me.Close() Dim CurrentForm As FrontPage *** CurrentForm.Enabled = True CurrentForm.Show() Else Plus += 1 If Plus >= 3 Then MessageBox.Show("Sorry, too many error !", _ "Password", MessageBoxButtons.OK, _ MessageBoxIcon.Exclamation) 'Close application End Else txtUserName.Clear() txtPassword.Clear() MessageBox.Show("Invalid User Name or Password !", _ "Password", MessageBoxButtons.OK, _ MessageBoxIcon.Error) End If End If txtUserName.Focus() End With End Sub Private Sub frmMgtLogin_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 'Connection string 'Con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Replace(Application.StartupPath, "bin", "") & "Pas.mdb;Mode=ReadWrite;Persist Security Info=False" Con.ConnectionString = "Jet OLEDB:Global Partial Bulk Ops=2;Jet OLEDB:Registry Path=;Jet OLEDB:Database L" & _ "ocking Mode=1;Data Source=""C:\Documents and Settings\Owner\My Documents\Visual S" & _ "tudio Projects\WindowsApplication1\ConsignmentShop.mdb"";Mode=Share Deny None;Jet" & _ " OLEDB:Engine Type=5;Provider=""Microsoft.Jet.OLEDB.4.0"";Jet OLEDB:System databas" & _ "e=;Jet OLEDB:SFP=False;persist security info=False;Extended Properties=;Jet OLED" & _ "B:Compact Without Replica Repair=False;Jet OLEDB:Encrypt Database=False;Jet OLED" & _ "B:Create System Database=False;Jet OLEDB:Don't Copy Locale on Compact=False;User" & _ " ID=Admin;Jet OLEDB:Global Bulk Transactions=1" UP.Connection = Con UP.CommandType = CommandType.Text UP.CommandText = "Select * From UserLogin Where UserID =? and PassID =?" End Sub End Class |
| All times are GMT -4. The time now is 4:49 pm. |
Forum system based on vBulletin Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
©2003 - 2009 DaniWeb® LLC