I am very sorry, however the bug status is still active. Curently, I have no fixed date on when the fix will be available.

Do you mind providing a sample of your scenario? Testing the issue in a simple scenario to show UXDialogBox object using DialogBoxServiceProvider, I could not procude any error. Here is the snippet:

    Private Sub UXPage_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
        DialogBoxServiceProvider.Show(New UXDialogBox1(), Nothing)
    End Sub

Based on my research, the error could occur if the changes parameter row structure and the WebGridDataProvider table row structure does not match. You could also provide a more detailed code, the select operation and the WebGrid setting you are using, so I could analyse the issue further.

My test show that the issue occurs on both AllowNodeEditing set to Yes or No. This issue seems to be caused by a bug. A bug report has been submitted.

Some client binding sample with web service is already provided in the WebGrid sample which you could view and analyse. These samples are:

- ClientBinding_BatchUpdate.aspx
- ClientBinding_Paging.aspx
- ClientBinding_VirtualGroupPaging.aspx
- ClientBinding_WebService.aspx

Regarding the select parameter, you could use the Tag property in the SelectDataSourceArguments object. You will need to set the property during the selecting client side method and parse the Tag property during the select server side event. Here is the snippet:

Selecting client side event:

<script type="text/javascript" language="javascript">
    function GetCustomers_Selecting(control, selectArguments) {
        selectArguments.Tag = "CategoryID=1;";
    } 
</script>

Client binding settings:

<ClientBindingSettings DataSourceType="WebService" ServiceUrl="WebService.asmx">
    <ServiceEvents Selecting="GetCustomers_Selecting" />
    <ServiceMethods SelectMethod="GetProducts" />
</ClientBindingSettings>

Select method definition:

[WebMethod]
public object GetProducts(DataSourceSelectArguments selectArguments)
{
    string selectParam = selectArguments.Tag;

    //Process selection
}