How do I disable a textbox the second time?
here is my code, In form load the textbox is disabled, unless the user will input an idnumber that is in the database. But what if the user will input an idnumber that is in the database then, input again another that is not,
That is where this code comes in, but it has problems, it doesnt disable the textbox in the event of a mouse click, what would be the proper way of doing this?
Private Sub Button12_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Button12.MouseClick
Dim NoAcc As String
Dim NoAccmod2 As String
Dim NoPas As String
Dim sqlcon As New MySqlConnection("Server=localhost; Database=school;Uid=root;Pwd=nitoryolai123$%^;")
Dim sqlcom As MySqlCommand = New MySqlCommand("Select * from student where IDNO= '" & TextBox14.Text & "' ", sqlcon)
sqlcon.Open()
Dim rdr As MySqlDataReader
rdr = sqlcom.ExecuteReader
If rdr.HasRows Then
rdr.Read()
NoAcc = rdr("IDNO")
If (TextBox14.Text <> NoAcc) Then
MsgBox("ID Number is not yet registered!, please register first in the general information before trying to register parents information", MsgBoxStyle.Information)
TextBox7.Enabled = False
TextBox8.Enabled = False
TextBox9.Enabled = False
TextBox10.Enabled = False
TextBox11.Enabled = False
TextBox12.Enabled = False
TextBox13.Enabled = False
End If
End If
At the top of the routine ALWAYS disable the textboxes, then ENABLE them if ID NUMBER matches...
Depending upon what you're actually trying to achieve here, also in the mouse-click you may want to clear the textbox of interest if the ID matches or set it to FOCUS if it does not (to allow them to see what they entered and make changes ... maybe they just mistyped?)
Related
I have a multi-level access login form made in VB.NET that uses an Access database in the back end.
If the user tries to log in when there is nothing entered in either of the text boxes (presses the log in button with nothing entered into either of the text boxes) and then tries to log in after entering their correct details, it allows it.
However, when the user enters either the username or password wrong, it will not allow them to log in after they have entered the correct details.
I am also having a problem where there is no case sensitivity (as long as the password has the correct characters in the correct order it doesn't matter if it is in upper case or lower case).
Imports System.Data.OleDb
Public Class frmLogin
Private DBCon As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;" &
"Data Source=|DataDirectory|\NewHotel.mdb;")
Private Sub btnLogIn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogIn.Click
If txtUsername.Text = "" Or txtPass.Text = "" Then
lblErrorEmpty.Visible = True
Else
Try
DBCon.Open()
Using cmd As New OleDbCommand("SELECT * FROM tblEmployees WHERE [Username] = #Usernname AND [Pass] = #Pass", DBCon)
cmd.Parameters.AddWithValue("Username", OleDbType.VarChar).Value = txtUsername.Text.Trim
cmd.Parameters.AddWithValue("Pass", OleDbType.VarChar).Value = txtPass.Text.Trim
Dim DBDA As New OleDbDataAdapter(cmd)
Dim DT As New DataTable
DBDA.Fill(DT)
If DT.Rows(0)("Type") = "Manager" Then
frmHomeManager.Show()
ElseIf DT.Rows(0)("Type") = "Receptionist" Then
frmHomeReceptionist.Show()
End If
End Using
Catch ex As Exception
lblErrorMatch.Visible = True
End Try
End If
End Sub
Thank you for your time :)
Don't declare connections outside of the method where they are used. Connections need to be closed and disposed. Using...End Using blocks handle this even when there is an error.
I have separated the user interface code from the database code. This makes the code easier to maintain
For OleDb the .Add method for parameters will help. Don't open the connection until directly before the .Execute. You are only retrieving a single piece of data so .ExecuteScalar should do the trick.
Private ConStr As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\NewHotel.mdb;"
Private Sub btnLogIn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogIn.Click
If txtUsername.Text = "" OrElse txtPass.Text = "" Then
MessageBox.Show("Please fill in both User Name and Password")
Exit Sub
End If
Dim UserType As Object
Try
UserType = GetUserType(txtUsername.Text.Trim, txtPass.Text.Trim)
Catch ex As Exception
MessageBox.Show(ex.Message)
Exit Sub
End Try
If UserType Is Nothing Then
MessageBox.Show("No record found")
ElseIf UserType.ToString = "Manager" Then
frmHomeManager.Show()
ElseIf UserType.ToString = "Receptionist" Then
frmHomeReceptionist.Show()
Else
MessageBox.Show($"{UserType} is not listed.")
End If
End Sub
Private Function GetUserType(UserName As String, Password As String) As Object
Dim Type As Object
Using DBCon As New OleDb.OleDbConnection(ConStr),
cmd As New OleDbCommand("SELECT Type FROM tblEmployees WHERE [Username] = #Usernname AND [Pass] = #Pass", DBCon)
cmd.Parameters.Add("#Username", OleDbType.VarChar).Value = UserName
cmd.Parameters.Add("#Pass", OleDbType.VarChar).Value = Password
DBCon.Open()
Type = cmd.ExecuteScalar.ToString
End Using
Return Type
End Function
Your check for the password is case insensitive, because you are storing the password directly and the database is case insensitive.
Your major problem is that you shouldn’t be storing the password in the database, you should be storing a cryptographically secure hash of the password in the database. This will require more work, but will be much safer.
You don’t have enough details to say why you can’t make a second attempt. I will say for reading a single record, I wouldn’t use a data table.
Dim sb As New MySqlConnectionStringBuilder
sb.Server = Form1.hostname.Text
sb.UserID = Form1.rootuser.Text
sb.Password = Form1.rootpassword.Text
sb.Database = Form1.hostdb.Text
sb.Port = Form1.hostport.Text
Using connection As New MySqlConnection(sb.ConnectionString)
Try
connection.Open()
Dim adapter1 As New MySqlDataAdapter(TextBox1.Text, connection)
Dim cmdb1 = New MySqlCommandBuilder(adapter1)
Dim ds As New DataSet
Dim words As String() = TextBox1.Text.Split(New Char() {" "c})
Dim tablenamewords = (words(3))
adapter1.Update(ds, tablenamewords)
Catch ex As MySqlException
MessageBox.Show(ex.Message)
Finally
connection.Dispose()
End Try
End Using
It's giving me this error:
Update unable to find TableMapping['creature_template'] or DataTable 'creature_template'.
I want to select items then use a DataGrid to update them.
Note: tablenamewords = "creature_template"
You can solve this in alot of different methods.
I prefer to update the DB with a single query every time the the user ends editing a cell.
BUT FIRST you have to bind a source to your DataGridView!
How to bind a source:
Go to your application design an click on your DataGridView
Click on the pause/start like little button as shown:
Click on the "ComboBox" like textbox labeled as "chose data source" as shown and click on it:
It will open a "form", click on the Add data source as shown:
Follow the wizard, you can do it without any furhter explanation!
Well done, you almost completed it. Just go in your code, and look for this sub:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.your_table_nameTableAdapter.Fill(Me.your_db_nameDataSet.your_table_name)
End Sub
The line inside your Form1_Load Sub will upload the data inside your DataGridView, leave it there if you want it to load with the form or cut/paste it wherever you like.
Now you can add this the code to programmatically update the DB:
Private Sub DataGridView1_CellEndEdit(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
Try
Dim location As Point = DataGridView1.CurrentCellAddress
Dim sqlCmd As String = "UPDATE table_name SET " & _
DataGridView1.Columns(location.X).Name.Replace("DataGridViewTextBoxColumn", "") & " = #Data " & _
"WHERE " & _
DataGridView1.Columns(0).Name.Replace("DataGridViewTextBoxColumn", "") & " = #ID"
Using myConn As New SqlConnection(My.Settings.VISURE_DA_PDFConnectionString)
myConn.Open()
Using myCmd As New SqlCommand(sqlCmd, myConn)
myCmd.Parameters.Add("#Data", SqlDbType.VarChar)
myCmd.Parameters.Add("#ID", SqlDbType.Int)
myCmd.Parameters("#Data").Value = DataGridView1.Rows(location.Y).Cells(location.X).Value
myCmd.Parameters("#ID").Value = DataGridView1.Rows(0).Cells(location.X).Value
myCmd.ExecuteNonQuery()
End Using
myConn.Close()
End Using
Catch ex As Exception
Err.Clear()
End Try
End Sub
Remarks:
location.X is the col index, location.Y is the row index
DataGridView1.Columns(0).Name This is my ID (primary key) and it is always in the first column. Change it with yours.
Don't forget to add .Replace("DataGridViewTextBoxColumn", "") whan you are getting your column name
As previously said, this code will update your DB every time the user edits one cell on your DataGridView updating only the edited cell. This is not a big issue because if you want to edit two ore more cell, every time you leave an edited cell the method DataGridView1_CellEndEdit is fired!
In my vb.net project, I have 3 forms. home_mdi, Viewfrm and AddDatafrm.
Viewfrm has an UltraWinGrid on it, which is displaying some data. When I click the add data button, AddDatafrm opens. When data is saved, the form then closes.
At this point, I want the UltraWinGrid on Viewfrm to update/refresh and display the data that I added. At the moment, it doesn't display it until I close Viewfrm and then open it again.
The images show this. (Data is not there at the start, it then gets added and does not appear. The final image is the form displaying the new data, after I've re-opened it.
How do I change this?
Current code:
To open the Add form
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
Using fp = New frmAddData(Globals.m_database)
If fp.ShowDialog() = DialogResult.OK Then
ugData.DataSource = Nothing
getPeople()
End If
End Using
End Sub
To save the entered information (on the Add form)
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
Dim m_cn As New OleDbConnection
m_cn = Globals.m_database.getConnection()
If txtFirstName.Text = "" Then
MsgBox("First name cannot be blank")
ElseIf txtLastName.Text = "" Then
MsgBox("Last name cannot be blank")
ElseIf txtAge.Text = "" Then
MsgBox("Age cannot be blank")
ElseIf txtPostCode.Text = "" Then
MsgBox("Postcode cannot be blank")
Else
Dim personID As Integer = database.SaveNewPerson(txtFirstName.Text, txtLastName.Text, txtAge.Text, txtPostCode.Text, m_cn)
MsgBox("Save successful")
txtFirstName.Text = ""
txtLastName.Text = ""
txtAge.Text = ""
txtPostCode.Text = ""
Globals.savedValue = True
Me.Close()
End If
End Sub
Call to load the database on the View form:
Public Sub getPeople()
Try
Dim sql As String = "SELECT * FROM tblPerson ORDER BY [personID] ASC;"
Dim cm As New OleDbCommand(sql, Globals.m_database.getConnection())
Dim da As New OleDbDataAdapter(cm)
Dim dt As New DataTable()
da.Fill(dt)
ugData.DataSource = dt
Catch Ex As Exception
mdi1.errorLog(Ex.Message, Ex.StackTrace)
MsgBox("Failed to retrieve data, refer to error log")
End Try
End Sub
In a WinForm app, a modal dialog is closed automatically by the engine if a button is pressed and its DialogResult property is set to anything but None. Then the Winform engine sets the form DialogResult to the same property of the button, exits from the ShowDialog call and returns the DialogResult property of the button clicked.
Usually this is more than enough to handle situations like yours above. (Or, in general situations where a user choose between Yes/No or OK/Cancel scenarios)
In your code (as explained in chat) you have the DialogResult property of the Save button set to DialogResult.None. This, means that the Winforms engine doesn't close automatically your form and you need to write your own closing routine.
But, if you forget to set the Form property DialogResult to DialogResult.OK, your calling code will never be able to refresh the grid because the test for DialogResult.OK fails.
So, whatever closing code you have to close the fromAddData instance, remember to set the form DialogResult property with
Me.DialogResult = DialogResult.OK
or, if something is gone wrong, with
Me.DialogResult = DialogResult.Cancel
The title may not be the best description but i would like help with having the button be disabled depending on which user click on it.
I know I should put the connection string in the web.config and I will but I'm not getting this button to work.
The HasRows yest looks if there is a row but i might do this wrong.
I have 3 rows in the table and with only one row = 'reports' all 3 users can still click the Button?
Can anyone help me here?
Protected Sub LeftMenuBarReportsButton_Click(sender As Object, e As System.EventArgs) Handles LeftMenuBarReportsButton.Click
Dim sqlconn As New SqlConnection
Dim sqCmd As New SqlCommand
Dim sqlreader As SqlDataReader
sqlconn.ConnectionString = "server = ....;Database=......;User ID=......;Password=...." 'SQL Connection String
sqCmd.Connection = sqlconn
sqlconn.Open()
sqCmd.CommandText = "SELECT UserID,Password,Role FROM UserCredentials WHERE Role = 'Reports'"
sqlreader = sqCmd.ExecuteReader
If sqlreader.HasRows Then
Response.Redirect("Reports.aspx")
Else
Dim click As Button = sender
click.Enabled = False
LeftMenuBarReportsButton.BackColor = Drawing.Color.Red
LeftMenuBarReportsButton.Text = "Access Denied"
End If
sqlreader.Close()
sqlconn.Close()
I am facing another issue. I want to associate a timer to my function.
Actually what i am doing is that i am tryin to store certain values in a database. A function is such that it calculates 5 values and stores them in a database. While storing them in the database it displays them in a textbox on the form. Now i want to display them one by one which it does. But it does it so fast that i can only see the last value that it enters in the database inside the textbox.
Can i make it show all the values slowly one by one.
Private Sub dbInsert(ByVal strfile As String, ByVal hashoffile As String, ByVal p As Integer)
'parameter to the above function (ByVal strfile As String)
DbConnection()
cmd = "select * from hashtable"
da = New OleDb.OleDbDataAdapter(cmd, con)
da.Fill(ds, "values")
maxrows = ds.Tables("values").Rows.Count
TextBox1.Text = p + 1
TextBox2.Text = hashoffile
TextBox3.Text = strfile
Dim cb As New OleDb.OleDbCommandBuilder(da)
Dim dsnewrow As DataRow
dsnewrow = ds.Tables("values").NewRow()
dsnewrow.Item("p_id") = TextBox1.Text
dsnewrow.Item("process_name") = TextBox2.Text
dsnewrow.Item("hash_value") = TextBox3.Text
ds.Tables("values").Rows().Add(dsnewrow)
da.Fill(ds)
da.Update(ds, "values")
'MsgBox("new Item added to database")
con.Close()
'System.Threading.Thread.Sleep(1000)
End Sub
Add a Timer Control to your form
Move your code (retrieving data and displaying data) to Timer Controls tick event
Set Timer controls Interval Property as you required, to make it slow displaying values.
Call TIMERCONTROLNAME.Enabled = True to start timer.