Refreshing DataTable

27 Jun 2005 2:35 PM

Simon

Hi All,

I have a DataGrid bound to a DataTable. Every once in a while I need
to refresh the data in the table so that the updated data is displayed
in the DataGrid. Here's how I am attempting this:

     'clear datatable
        datatbl.Rows.Clear()

        If PLCCount() <> 0 Then
            'add rows to datatable containing PLC info
            For p = 0 To PLCCount() - 1
                Dim rowinfo As DataRow
                rowinfo = datatbl.NewRow()
                rowinfo("ID") = plcID(p)
                rowinfo("Road") = PLCRoadName(p)
                rowinfo("Start Time") = MyDate(plcStartTime(p))
                rowinfo("End Time") = MyDate(plcEndTime(p))
                rowinfo("Location") = plcLocationDescription(p)
                rowinfo("Cause") = plcCause(p)
                'add info to datatable
                Try
                  'out-of-bounds error here
                  datatbl.Rows.Add(rowinfo)
                Catch ex As Exception
                    MessageBox.Show(ex.Message)
                End Try
            Next p
            'bind to datatable to datagrid
            grdClosures.DataSource = datatbl
        End If

I clear the rows in the DataTable and re-populate. However, when I try
and add the new rows i get an out-of-bounds exception in the Add
function.

This has something to do with the fact that I clear the rows and then
create new ones but I don't know nor understand why this is a problem.

Can anyone help?

Many thanks

Simon

27 Jun 2005 6:08 PM

Cor Ligthert

Simon,

I made this sample now. I don't set it on our site it is to simple for my
opinion. Can you have a look for yourself what that means accoording your
code.

At least there is no reason to set that datasource again in your code as you
do now.

\\\
Private Sub Form1_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
        Dim dt As DataTable = CreateTables()
        dt.DefaultView.Sort = "State"
        DataGrid1.DataSource = dt
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, _
       ByVal e As System.EventArgs) Handles Button1.Click
        Dim dt As DataTable = DirectCast(DataGrid1.DataSource, DataTable)
        'The row above is to set the datatable not global not something
accoording your problem
        dt.LoadDataRow(New Object() {"Michael Coles", "New Jersey"}, True)
    End Sub
    'To have a table to use is one created below
    Private Function CreateTables() As DataTable
        Dim dt As New DataTable("Persons")
        dt.Columns.Add("Name", GetType(System.String))
        dt.Columns.Add("State", GetType(System.String))
        dt.LoadDataRow(New Object() {"Ken Tucker", "Florida"}, True)
        dt.LoadDataRow(New Object() {"Cor Ligthert", "Holland"}, True)
        Return dt
    End Function
///
I hope this helps,

Cor