Q: Combobox cell value data source datagridview 
Below in image i have Reason as combo box which has three options .
On selecting first value such as In house Rework, Second column Responsible party which is
also combo box should get populated with list collection and so like on selection
of another value from Reason combo box Responsible party should get populated with
another list collection.
Since i have attempted on end edit of gridview and it's happening to show value but if on next row i change my Rework combo box value the previous value of Responsible party doesn't retain its value.
So how can i achieve to prevent this case.
So any help is appreciated.

A: Are you trying to bind the other two combo boxes based off the value selected in the reason? If so I would use the CellValueChanged event in the Data Grid's events and you can programmatically build a list and databind it. If this is what you want to do I'll post an example here, if not please clarify so I can be help.
Private Sub dgVendors_CellValueChanged(sender As System.Object, e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgVendors.CellValueChanged

        If dgVendors.Columns(e.ColumnIndex).HeaderText = "Reason" Then

            CType(dgVendors.Rows(e.RowIndex).Cells(""), DataGridViewComboBoxCell).DataSource = Nothing
            CType(dgVendors.Rows(e.RowIndex).Cells(""), DataGridViewComboBoxCell).DisplayMember = ""
            CType(dgVendors.Rows(e.RowIndex).Cells(""), DataGridViewComboBoxCell).ValueMember = ""

        ElseIf dgVendors.Columns(e.ColumnIndex).HeaderText = "Responsible Party" Then

            CType(dgVendors.Rows(e.RowIndex).Cells(""), DataGridViewComboBoxCell).DataSource = Nothing
            CType(dgVendors.Rows(e.RowIndex).Cells(""), DataGridViewComboBoxCell).DisplayMember = ""
            CType(dgVendors.Rows(e.RowIndex).Cells(""), DataGridViewComboBoxCell).ValueMember = ""

        End If

End Sub


A: If you want to handle the selection change event of the dropdown, you can handle the EditingControlShowing event of the DataGridView.
There is also an MSDN page which might help you out.
Also, make sure you change the DataSource of the DataGridViewComboBoxCell on the CurrentRow, not of the DataGridViewComobBoxColumn.
