Hi All,
I have been trying to handle concurrency violations for my app to no avail. The app is going on a network so these may be a regular exception to be dealt with.
Load Datagridview:
Here I make changes by different users to cause a concurrency violation deliberately. Then I attempt to update the database as follows.
No matter what I have tried, I either get the database and datagridview having same data as the left after the first user change (second user change causing the violation), when I am wanting to overwrite the first users change, or I get another concurrency violation. I have been referring some MS documentation but it is from about 2005.
I am confident there is no other user interactions with database other than mentioned above and I have also tried changing all to dataset from datatable with same result.
Could anybody see where I am going wrong, I am thinking the merge is not working how I have coded it but am stumped after a long day of trying!
Many Thanks.
I have been trying to handle concurrency violations for my app to no avail. The app is going on a network so these may be a regular exception to be dealt with.
Load Datagridview:
Code:
Try
con = New MySqlConnection(cs)
If Not con.State = ConnectionState.Open Then
con.Open()
End If
cmd = New MySqlCommand("SELECT * FROM `" & name & "`", con)
da2 = New MySqlDataAdapter(cmd)
dt2 = New DataTable
da2.Fill(dt2)
cb2 = New MySqlCommandBuilder(da2)
With dtgRecipes
.DataSource = ds2.Tables(0)
End With
Catch ex As ExceptionCode:
UpdateDatabase()
Private Sub UpdateDatabase()
Try
da2.Update(dt2)
dt2.AcceptChanges()
Catch dbcx As DBConcurrencyException
createTempDataTable()
Dim response As DialogResult = MessageBox.Show("Overwrite?", "Concurrency Exception", MessageBoxButtons.YesNo)
ProcessDialogResult(response)
Catch ex As Exception
MessageBox.Show("An error was thrown while attempting to update the database.")
End Try
End Sub
Private tempDataTable As New DataTable()
Private Sub createTempDataTable()
Dim name As String = cmbRecipeNames.Text
Try
con = New MySqlConnection(cs)
If Not con.State = ConnectionState.Open Then
con.Open()
End If
cmd = New MySqlCommand("SELECT * FROM `" & name & "`", con)
da = New MySqlDataAdapter(cmd)
da.Fill(tempDataTable)
Catch ex As Exception
Private Sub ProcessDialogResult(ByVal response As DialogResult)
Select Case response
Case DialogResult.Yes
dt2.Merge(tempDataTable, True)
da2.Update(dt2)
dt2.AcceptChanges()
Case DialogResult.No
ds2.Merge(tempDataTable)
MessageBox.Show("Update cancelled")
End Select
End SubNo matter what I have tried, I either get the database and datagridview having same data as the left after the first user change (second user change causing the violation), when I am wanting to overwrite the first users change, or I get another concurrency violation. I have been referring some MS documentation but it is from about 2005.
I am confident there is no other user interactions with database other than mentioned above and I have also tried changing all to dataset from datatable with same result.
Could anybody see where I am going wrong, I am thinking the merge is not working how I have coded it but am stumped after a long day of trying!
Many Thanks.