public event ASPxClientLayoutHandler ClientLayout

Public Event ClientLayout As ASPxClientLayoutHandler

protected void ASPxGridView1_ClientLayout(object sender, 
DevExpress.Web.ASPxClientLayoutArgs e) {
    if (e.LayoutMode == DevExpress.Web.ClientLayoutMode.Saving) {
        SaveUserLayoutToDatabase(userID, "AccountGrid", e.LayoutData);
    }
    else {
        if (System.IO.File.Exists(fileName))
            e.LayoutData = RestoreUserLayoutFromDatabase(userID, "AccountGrid");
    }
}

Protected Sub ASPxGridView1_ClientLayout(sender As Object,_
e As DevExpress.Web.ASPxClientLayoutArgs)
   If e.LayoutMode = DevExpress.Web.ClientLayoutMode.Saving Then
      SaveUserLayoutToDatabase(userID, "AccountGrid", e.LayoutData)
   Else
      If File.Exists(fileName) Then
         e.LayoutData = RestoreUserLayoutFromDatabase(userID, "AccountGrid")
      End If
   End If
End Sub

<dx:ASPxGridView ID="MasterGrid" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1"
    KeyFieldName="CategoryID" OnDetailRowExpandedChanged="MasterGrid_DetailRowExpandedChanged">
    <Columns>
        <dx:GridViewCommandColumn ShowClearFilterButton="True"/>
        <dx:GridViewDataTextColumn FieldName="CategoryID" ReadOnly="True" >
            <EditFormSettings Visible="False" />
        </dx:GridViewDataTextColumn>
        <dx:GridViewDataTextColumn FieldName="CategoryName" />
        <dx:GridViewDataTextColumn FieldName="Description" />
    </Columns>
    <Settings ShowFilterRow="True" ShowGroupPanel="True" />
    <SettingsDetail ShowDetailRow="True" />
    <Templates>
        <DetailRow>
            <dx:ASPxGridView ID="DetailGrid" runat="server" AutoGenerateColumns="False" 
                DataSourceID="SqlDataSource2" KeyFieldName="ProductID" 
                OnBeforePerformDataSelect="DetailGrid_BeforePerformDataSelect"
                OnClientLayout="DetailGrid_ClientLayout">
                <Columns>
                    <dx:GridViewDataTextColumn FieldName="ProductID" ReadOnly="True" >
                        <EditFormSettings Visible="False" />
                    </dx:GridViewDataTextColumn>
                    <dx:GridViewDataTextColumn FieldName="ProductName" />
                    <dx:GridViewDataTextColumn FieldName="CategoryID" />
                    <dx:GridViewDataTextColumn FieldName="UnitPrice" />
                </Columns>
            </dx:ASPxGridView>
        </DetailRow>
    </Templates>
</dx:ASPxGridView>

protected void Page_Init(object sender, EventArgs e) {
    if (!IsPostBack)
        Session.Clear();
}
protected void DetailGrid_BeforePerformDataSelect(object sender, EventArgs e) {
    Session["CategoryID"] = ((ASPxGridView)sender).GetMasterRowKeyValue();
}
protected void DetailGrid_ClientLayout(object sender, DevExpress.Web.ASPxClientLayoutArgs e) {
    ASPxGridView grid = sender as ASPxGridView;
    string key = grid.GetMasterRowKeyValue().ToString();
    if (e.LayoutMode == DevExpress.Web.ClientLayoutMode.Loading && Session["DetailGrid"+key] != null ) {
        e.LayoutData = (string)Session["DetailGrid"+key];
    }
    else {
        Session["DetailGrid"+key] = e.LayoutData;
    }

}
protected void MasterGrid_DetailRowExpandedChanged(object sender, ASPxGridViewDetailRowEventArgs e) {
    if (e.Expanded == false) {
        string key = MasterGrid.GetRowValues(e.VisibleIndex, MasterGrid.KeyFieldName).ToString();
        Session["DetailGrid" + key] = null;  
    }
}

Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
    If (Not IsPostBack) Then
    Session.Clear()
    End If
End Sub

Protected Sub DetailGrid_BeforePerformDataSelect(ByVal sender As Object, ByVal e As EventArgs)
  Session("CategoryID") = (CType(sender, ASPxGridView)).GetMasterRowKeyValue()
End Sub

Protected Sub DetailGrid_ClientLayout(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxClientLayoutArgs)
  Dim grid As ASPxGridView = TryCast(sender, ASPxGridView)
  Dim key As String = grid.GetMasterRowKeyValue().ToString()
  If e.LayoutMode = DevExpress.Web.ClientLayoutMode.Loading AndAlso Session("DetailGrid" & key) IsNot Nothing Then
    e.LayoutData = CStr(Session("DetailGrid" & key))
  Else
    Session("DetailGrid" & key) = e.LayoutData
  End If
End Sub

Protected Sub MasterGrid_DetailRowExpandedChanged(ByVal sender As Object, ByVal e As ASPxGridViewDetailRowEventArgs)
  If e.Expanded = False Then
    Dim key As String = MasterGrid.GetRowValues(e.VisibleIndex, MasterGrid.KeyFieldName).ToString()
    Session("DetailGrid" & key) = Nothing
  End If
End Sub