DataSet and CurrencyManager problem

[al]

Greetings,

I have this probelm synchronising dataset with the currencymanager.
I basically have MDI app with a form for data entry and search. In
the search part of it,there are two options for the user, either get
all records or filtered ones based on entrer employeeID. The problem
i'm facing is that when I search for second time,be the first time
getting all records or filtereing, the currencymanager gets
out-of-synch and doesn't udpate form. I do clear binding the second
time and currencymanager shows zero counts of elements. Here is the
code: if I clear bindings, can I user sam currencymanager again, if
yes, how????

Imports System.Data
Imports System.Data.SqlClient

Public Class Form1

Inherits System.Windows.Forms.Form

Dim frmemp As New Employees
Dim frmcus As New customers
Dim ds As New DataSet
Dim str As String = ("data source=pc1;initial
catalog=northwind;integrated security=sspi")
Dim sql As String = "select * from employees"
Dim sql2 As String = "select * from employees where employeeid="&
empid.text
Dim mydatabinding As BindingManagerBase
Dim mycm As CurrencyManager
Dim mybc As BindingContext
Dim activeChild As Form = Me.ActiveMDIChild
Dim da1 As SqlDataAdapter
Dim da2 As SqlDataAdapter = New SqlDataAdapter(sql2, str)




Private Sub Search_ButtonClick(ByVal sender As System.Object, ByVal e
As System.Windows.Forms.ToolBarButtonClickEventArgs) Handles
ToolBar1.ButtonClick
Try

Select Case ToolBar1.Buttons.IndexOf(e.Button)
Case 0
Case 1
If (ds.Tables("employees") Is Nothing) Then
If frmemp.txtID.Text.Length > 0 Then
da1 = New SqlDataAdapter(sql2, str)
da1.Fill(ds, "Employees")
dobinding()
ds_changexposition()
Else
da1 = New SqlDataAdapter(sql, str)
da1.Fill(ds, "Employees")
mycm = CType(Me.BindingContext(ds,
"Employees"), CurrencyManager)
dobinding()
ds_changexposition()
End If
ElseIf Not (ds.Tables("employees") Is Nothing)
Then
ds.Tables("employees").Clear()
clearbinding()
da1.Fill(ds, "Employees")
dobinding()
ds_changexposition()
End If
Case 2
Case 3
clearbinding()
End Select
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub



Sub clearbinding()
Dim ctl As Control
Dim txt As Control
Dim i As Short = 2

ds.Tables("employees").Reset()
For Each ctl In frmemp.Controls
If TypeOf ctl Is GroupBox Then
For Each txt In ctl.Controls
If TypeOf txt Is TextBox Then
txt.Text = ""
txt.DataBindings.Clear()
End If
Next
End If
Next
ds_changexposition()
End Sub



Sub dobinding()
frmemp.txtID.DataBindings.Add("text", ds,
"employees.employeeid")
frmemp.txtlastname.DataBindings.Add("text", ds,
"employees.lastname")
frmemp.txtfirstname.DataBindings.Add("text", ds,
"employees.firstname")
frmemp.txttitle.DataBindings.Add("text", ds,
"employees.title")
End Sub



Sub ds_changexposition()

Me.StatusBar1.Panels(1).Text = ((mycm.Position + 1).ToString)
+ "of" + (mycm.Count.ToString)
End Sub



Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
frmemp.MdiParent = Me
frmcus.MdiParent = Me
Me.StatusBar1.Panels(0).Text = Now.ToShortTimeString

End Sub



Private Sub customers_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles customers.Click
frmcus.Show()
End Sub




Private Sub Employees_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Employees.Click
frmemp.Show()
End Sub




Private Sub ToolBar2_ButtonClick(ByVal sender As System.Object,
ByVal e As System.Windows.Forms.ToolBarButtonClickEventArgs) Handles
ToolBar2.ButtonClick
Select Case ToolBar2.Buttons.IndexOf(e.Button)
Case 0
mycm.Position = 0
ds_changexposition()
Case 1
mycm.Position += 1
ds_changexposition()
Case 2
mycm.Position -= 1
ds_changexposition()
Case 3
mycm.Position = mycm.Count - 1
ds_changexposition()
End Select
End Sub

End Class

 

[Miha Markic]

Hi,

Greetings,

I have this probelm synchronising dataset with the currencymanager.
I basically have MDI app with a form for data entry and search. In
the search part of it,there are two options for the user, either get
all records or filtered ones based on entrer employeeID. The problem
i'm facing is that when I search for second time,be the first time
getting all records or filtereing, the currencymanager gets
out-of-synch and doesn't udpate form. I do clear binding the second
time and currencymanager shows zero counts of elements. Here is the
code: if I clear bindings, can I user sam currencymanager again, if
yes, how????

Why are you removning/adding bindings in first place?
The Reset methods is the culprit of your problem (I think that there is no
need to invoke it - just leave it out).

 

[al]

Hi,



Why are you removning/adding bindings in first place?
The Reset methods is the culprit of your problem (I think that there is no
need to invoke it - just leave it out).

The reasone for the removing/adding is this. when a user enters and
employeeID to search for, he/she also wants to use the same form to
get all records from same table and to same ds and dt. So it makes
sence to clear dt for the new reocrds and with that also clear the
bindings.