public bool IsSetData { get; }

Public ReadOnly Property IsSetData As Boolean

e.Value = _Cache.GetValue(e.Row);
if (e.IsSetData)
    _Cache.SetValue(e.Row, e.Value);

private void GridView1_CustomUnboundColumnData(object sender, DevExpress.XtraGrid.Views.Base.CustomColumnDataEventArgs e) {
    if (e.IsSetData)
        return;

e.Value = e.ListSourceRowIndex == SelectedDataSourceRowIndex;
if (e.IsSetData)
    if (e.Value.Equals(true))

e.Value = unboundData[e.ListSourceRowIndex];
else if (e.IsSetData)
    unboundData[e.ListSourceRowIndex] = (bool)e.Value;

If e.IsGetData Then e.Value = _Cache.GetValue(e.Row)
    If e.IsSetData Then _Cache.SetValue(e.Row, e.Value)
End Sub

Private Sub GridView1_CustomUnboundColumnData(ByVal sender As Object, ByVal e As Views.Base.CustomColumnDataEventArgs)
    If e.IsSetData Then Return
    Dim view As GridView = TryCast(sender, GridView)

End If
If e.IsSetData Then
    If e.Value.Equals(True) Then

e.Value = unboundData(e.ListSourceRowIndex)
ElseIf e.IsSetData Then
    unboundData(e.ListSourceRowIndex) = CBool(e.Value)