我如何从vb.net添加到Access数据库

Question

Am still learning VB and database but I have a little problem. My codes works but when I try to look into the database I don't find all what are been saved, how do I rectify it? and also the edit and delete. thanks

Here is my code:

Public Class Form1


Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    'TODO: This line of code loads data into the 'ItemsDataSet.Items' table. You can move, or remove it, as needed.
    Me.ItemsTableAdapter.Fill(Me.ItemsDataSet.Items)
    'TODO: This line of code loads data into the 'ItemsDataSet.Items' table. You can move, or remove it, as needed.
    Me.ItemsTableAdapter.Fill(Me.ItemsDataSet.Items)
    'TODO: This line of code loads data into the 'ItemsDataSet.Items' table. You can move, or remove it, as needed.
    Me.ItemsTableAdapter.Fill(Me.ItemsDataSet.Items)

End Sub

Private Sub ItemsDataSetBindingSource_CurrentChanged(sender As Object, e As EventArgs)

End Sub

Private Sub btnedit_Click(sender As Object, e As EventArgs) Handles btnedit.Click

    ItemsBindingSource.EndEdit()
    ItemsTableAdapter.Update(ItemsDataSet.Items)
    MsgBox("Saved")
End Sub

Private Sub btadd_Click(sender As Object, e As EventArgs) Handles btnadd.Click
    ItemsBindingSource.AddNew()
    MsgBox("Added Successfully")



End Sub

Private Sub btndelete_Click(sender As Object, e As EventArgs) Handles btndelete.Click
    ItemsBindingSource.RemoveCurrent()
    MsgBox("Item Deleted")
End Sub



Private Sub btnexit_Click(sender As Object, e As EventArgs) Handles btnexit.Click
    Close()

End Sub

Private Sub btnprevious_Click(sender As Object, e As EventArgs) Handles btnprevious.Click
    ItemsBindingSource.MovePrevious()
End Sub

Private Sub btnnext_Click(sender As Object, e As EventArgs) Handles btnnext.Click
    ItemsBindingSource.MoveNext()
End Sub

End Class

Answer 1

You probably have your MDB (ACCDB) file included in your project files. If you check the properties associated with this project file you will find one named Copy to Output Directory. Set this to Copy Always.

Also your connection string contains the shortcut Data Source = "|DataDirectory|\\yourdb.mdb"

If this scenario is correct, then you start your application and the MDB / ACCDB file is copied from the original location to the BIN\\DEBUG directory. You insert your data there without error. When you stop the debug session to fix errors or other problems you restart your application and the fresh copy (but empty) of your db is copied again in the output directory.

To fix this, set the property to Copy Never or change your connection string to point to a fixed location.