Could you please inform me about how did you bind the DataTable (as the data source of WebGrid) in code behind? Currently I suspect that the data binding process might be located in Page_Load event instead of the InitializeDataSource event of WebGrid.

Look forward to hearing back from you so that we can assist you further.

Thank you for the reply.

I was doing the data binding process in de Page_Load event. I change this to the InitializeDataSource event and the error screen change. Now is the attachment file.

 Protected Sub WebGrid2_InitializeDataSource(sender As Object, e As ISNet.WebUI.WebGrid.DataSourceEventArgs) Handles WebGrid2.InitializeDataSource
        Dim Consultas As New Consultas
        Dim Acceso As New AccesoDatos
        Dim Funciones As New Funciones
        Dim tabla As New DataTable
        'tabla = Consultas.ConsultaCategorias()
        'Dim Total As Int32 = Funciones.SumarGrid(tabla, "Clientes")
        'Funciones.AddColPromedio(tabla, 1, 2, Total)
        'Funciones.AddColCodigo(tabla)
        'WebGrid1.DataSource = tabla
        'WebGrid1.DataBind()
        Dim tabla2 As New DataTable
        tabla2 = Consultas.ConsultaDuraciones()
        Dim Total As Int32 = Funciones.SumarGrid(tabla2, "Clientes")
        Funciones.AddColPromedio(tabla2, 1, 2, Total)
        WebGrid2.DataSource = tabla2
        WebGrid2.DataBind()
    End Sub

 This is the code behind.

All codes related to the assignment of data source to the WebGrid component should be place in InitializeDataSource server side event of WebGrid. Avoid assigning the DataSource property to the Grid object such as WebGrid2.DataSource = tabla2, since in the InitializeDataSource event, developers could obtain an object of DataSourceEventArgs here using e.

Please replace WebGrid2.DataSource = tabla2 with e.DataSource = tabla2. The code listing should looks like below.

Protected Sub Samplegrid_InitializeDataSource(ByVal sender As Object, ByVal e As ISNet.WebUI.WebGrid.DataSourceEventArgs) Handles WebGrid1.InitializeDataSource
    ...
    Funciones.AddColPromedio(tabla2, 1, 2, Total)
    e.DataSource = tabla2
    WebGrid2.DataBind()
End Sub

This should helps. Please let us know if the problem still persists.

It Works!!!

Thank You very much.