Can't display dataset in windows form datagrid

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hi all, i have a window application which make use of a timer class, whereby
every 5 seconds i have to refresh a datagrid,below is the codes

Public Sub TimerFired(ByVal sender As Object, _
ByVal e As System.Timers.ElapsedEventArgs)




'Label1.Text = "Server Time = " & e.SignalTime.ToString
tape()
end sub
Private Function tape()

Dim i As Integer
Dim ds3 As New DataSet
Dim ds4 As New DataSet
ds4 = a.RetrievePatient1()
Dim foodtable As DataTable
Dim idcolumn As DataColumn
Dim namecolumn As DataColumn
Dim foodemandcolumn As DataColumn

Dim row As DataRow
'make a table
foodtable = New DataTable("Food")

'make a column
idcolumn = New DataColumn("PatientID")
idcolumn.DefaultValue = "<PatientID>"
'idcolumn.DataType = Type.GetType("System.string")
foodtable.Columns.Add(idcolumn)

namecolumn = New DataColumn("Name")
idcolumn.DefaultValue = "<Name>"
'idcolumn.DataType = Type.GetType("System.string")
foodtable.Columns.Add(namecolumn)

foodemandcolumn = New DataColumn("DemandFood")
foodemandcolumn.DefaultValue = "<DemandFood>"
'idcolumn.DataType = Type.GetType("System.string")
foodtable.Columns.Add(foodemandcolumn)

'a.RetrievePatient(patID)
'add row of data
For i = 0 To ds4.Tables(0).Rows.Count() - 1
'If TextBox1.Text = ds3.Tables(0).Rows(i)(0) Then
row = foodtable.NewRow
row("PatientID") = ds4.Tables(0).Rows(i)("PatientID")
row("Name") = ds4.Tables(0).Rows(i)("Name")
row("DemandFood") = ds4.Tables(0).Rows(i)("DemandFood")
foodtable.Rows.Add(row)





'DataGrid2.SetDataBindinga(ds2,"DemanfFood)

'End If
Next
ds4.Tables.Add(foodtable)

DataGrid2.SetDataBinding(ds4, "Food")
End Function
With the above coding data could not be retrieve to the datagrid
*datagrid couls br filled if the above codes are placed in a Form_Load or
button_Onclick

vitz...
 
It looks like every time your timer fires and calls tape() you are adding
another table with the name "food" to your dataset. That should throw a
DuplicateNameException. Remove your old table (or repopulate it instead of
creating a new one) before you try and retrieve new data.
 
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