VB.NET SQL Database locked - vb.net

Question

My data table is loaded in 2 places, a DataGridView and a ComboBox
The ComboBox is to select a record to edit (a TextBox to enter a new value)
And the DataGridView is to see the changes (I gave up (for now) updating directly from the DataGridView)
Private Sub EditLoc_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Try
con.Open()
Dim sql = Nothing
sql = "SELECT Location FROM Location"
Dim cmdDataGrid As SQLiteCommand = New SQLiteCommand(sql, con)
Dim da As New SQLiteDataAdapter
da.SelectCommand = cmdDataGrid
Dim dt As New DataTable
da.Fill(dt)
DataGridView1.DataSource = dt
Dim readerDataGrid As SQLiteDataReader = cmdDataGrid.ExecuteReader()
con.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try
Try ' TRY CATCH for combobox
con.Open()
cmd.Connection = con
cmd.CommandText = "SELECT Location FROM Location"
dr = cmd.ExecuteReader()
' Fill a combo box with the datareader
Do While dr.Read = True
ComboBox1.Items.Add(dr.GetString(0))
Loop
If ComboBox1.Items.Count > 0 Then
ComboBox1.SelectedIndex = 0 ' The first item has index 0 '
End If
con.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
This works perfectly
Picture
The problem is when I click Save, the app hangs a while, and then I get the "Database is locked" error picture
Here is the code for the Save button:
Private Sub Savebtn_Click(sender As Object, e As EventArgs) Handles Savebtn.Click
Try
con.Open()
cmd = con.CreateCommand
cmd.CommandText = "UPDATE Location set Location = '" & TextBox1.Text & "' WHERE Location = '" & ComboBox1.Text & "'"
cmd.ExecuteNonQuery()
cmd.Dispose()
con.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Thanks for the help

Answer 1

I fixed this problem by removing all "cmd.Dispose()", "da.Dispose()" and "con.Close()" from the code, leaving them ONLY in
Private Sub Closebtn_Click(sender As Object, e As EventArgs) Handles Closebtn.Click
da.Dispose()
cmd.Dispose()
con.Close()
Dim fems As New EMS
fems.Show()
Me.Close()
End Sub
On Form Load I have
Private Sub EditLoc_Load(sender As Object, e As EventArgs) Handles MyBase.Load
con.Open()
Call pull()
End Sub
And the Pull sub has all the rest...
Private Sub pull()
Try
Dim sql = Nothing
sql = "SELECT Location FROM Location"
Dim cmdDataGrid As SQLiteCommand = New SQLiteCommand(sql, con)
da.SelectCommand = cmdDataGrid
Dim dt As New DataTable
da.Fill(dt)
DataGridView1.DataSource = dt
Dim readerDataGrid As SQLiteDataReader = cmdDataGrid.ExecuteReader()
Catch ex As Exception
MsgBox(ex.Message)
End Try
Try ' TRY CATCH for combobox
cmd.Connection = con
cmd.CommandText = "SELECT Location FROM Location"
dr = cmd.ExecuteReader()
' Fill a combo box with the datareader
Do While dr.Read = True
ComboBox1.Items.Add(dr.GetString(0))
Loop
If ComboBox1.Items.Count > 0 Then
ComboBox1.SelectedIndex = 0 ' The first item has index 0 '
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
And here is my Save button
Private Sub Savebtn_Click(sender As Object, e As EventArgs) Handles Savebtn.Click
If Not TextBox1.Text = Nothing Then
Try
cmd = con.CreateCommand
cmd.CommandText = "UPDATE Location set Location = '" & TextBox1.Text & "' WHERE Location = '" & ComboBox1.Text & "'"
cmd.ExecuteNonQuery()
Catch ex As Exception
MsgBox(ex.Message)
End Try
Call pull()
TextBox1.Text = Nothing
End If
End Sub
Now everything is working, no errors!
Calling pull() after saving will update the DataGridView
Thanks for the help