Question

I am trying to update a datagridview and a chart.
I have a class and in that class I have a function that returns a datatable from database.
I need the bindingSource because this is how I update chart (bar)
Unfortunately when the chart is Pie I need to use a datatable for updating
So when I load the form I have:

gbsGraph.DataSource = graphFunctions.prepareData() 'gbsGraph is a BindingSource
gdtGraphData = graphFunctions.prepareData() 'gdtGraphData  isDataTable
gdv.DataSource = gbsGraph 'gdv is my datagridview
AddHandler gdtGraphData.RowChanged, AddressOf gdtGraphData_RowChanged 'add event for update piechart
fillChart()'code to fill the chart

When the user press the refresh button:

Private Sub tsmiRefresh_Click(sender As System.Object, e As System.EventArgs) Handles tsmiRefresh.Click
  gbsGraph.DataSource = graphFunctions.prepareData()' this works and dgv and my bar charts are updated
  gdtGraphData = graphFunctions.prepareData()  'this is should trigger the event gdtGraphData.RowChanged but it doesn't   
End Sub

My custom event for DataRowChange:

Private Sub gdtGraphData_RowChanged(ByVal sender As Object, ByVal e As DataRowChangeEventArgs)
    'Here is code to refill the Pie chart
    'but the event isn't fired
End Sub

So my question is how I can update my datatable and fire the gdtGraphData_RowChanged event?

Thanks
T

Answer 1

The row changed event is raised when a value inside a row inside a datatable is changed, not when you put a new instance of a datatable into a variable …

An example:

' This will raise the rowchanged event
gdtGraphData.Rows(0)("someField") = 123

' This will not!
gdtGraphData = graphFunctions.prepareData()

You will have to put the code to refill the Pie chart inside the tsmiRefresh_Click …