Clone reference type properties with CustomButtonCallback - asp.net

Question

I'm trying to follow the DevExpress documentation example on cloning rows. The basics are easy to get right, but things get tricky when you try to clone properties other than value types.
First attempt / setting up a repro:
I've narrowed my real scenario to a small(ish) repro of the problem. The following is all part of a freshly created ASP.NET 2.0 webforms application. First, suppose these domain objects (that'll double as DTO's here too):
public class Qualification
{
public long Id { get; set; }
public string Title { get; set; }
}
public class Person
{
public long Id { get; set; }
public string Name { get; set; }
public Qualification Qualification { get; set; }
}
Then there are two quick 'n dirty data source classes like so:
public class QualificationOds
{
public static List<Qualification> Qualificiations = new List<Qualification>
{
new Qualification { Id = 1, Title = "Doctore" }
};
public List<Qualification> GetRecords()
{
return Qualificiations;
}
}
public class PeopleOds
{
public List<Person> GetRecords()
{
return new List<Person>
{
new Person
{
Id = 1,
Name = "John Doe",
Qualification = QualificationOds.Qualificiations[0]
}
};
}
}
The default.aspx page will first register dx to DevExpress namespaces:
<%# Register Assembly="DevExpress.Web.ASPxGridView.v11.1, Version=11.1.11.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web.ASPxGridView" TagPrefix="dx" %>
<%# Register Assembly="DevExpress.Web.ASPxEditors.v11.1, Version=11.1.11.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web.ASPxEditors" TagPrefix="dx" %>
And have a single form with this code in it:
<asp:ObjectDataSource runat="server" ID="peopleDataSource" TypeName="DevxTest.PeopleOds" SelectMethod="GetRecords" />
<asp:ObjectDataSource runat="server" ID="qualificationsDataSource" TypeName="DevxTest.QualificationOds" SelectMethod="GetRecords" />
<dx:ASPxGridView
runat="server"
id="grvPeople"
KeyFieldName="Id"
DataSourceID="peopleDataSource"
OnCustomButtonCallback="grid_CustomButtonCallback"
OnInitNewRow="grid_InitNewRow">
<Columns>
<dx:GridViewCommandColumn>
<EditButton Visible="true" />
<CustomButtons>
<dx:GridViewCommandColumnCustomButton ID="Clone" Text="Clone" />
</CustomButtons>
</dx:GridViewCommandColumn>
<dx:GridViewDataTextColumn FieldName="Name" />
<dx:GridViewDataComboBoxColumn FieldName="Qualification.Id" >
<PropertiesComboBox
DataSourceID="qualificationsDataSource"
TextField="Title"
ValueField="Id"
ValueType="System.Int64" />
</dx:GridViewDataComboBoxColumn>
</Columns>
</dx:ASPxGridView>
The code behind contains the code to clone a row into a fresh edit form, based on aforementioned DevExpress example, like so:
private string[] fieldsToCopy = { "Name", "Id" };
private Hashtable valuesToClone;
protected void grid_CustomButtonCallback(object sender, ASPxGridViewCustomButtonCallbackEventArgs e)
{
if (e.ButtonID != "Clone") return;
valuesToClone = new Hashtable();
foreach (var fieldName in fieldsToCopy)
{
valuesToClone[fieldName] = grvPeople.GetRowValues(e.VisibleIndex, fieldName);
}
grvPeople.AddNewRow();
}
protected void grid_InitNewRow(object sender, DevExpress.Web.Data.ASPxDataInitNewRowEventArgs e)
{
if (valuesToClone == null) return;
foreach (string fieldName in fieldsToCopy)
{
e.NewValues[fieldName] = valuesToClone[fieldName];
}
}
This works for the Name property, but not so much for the Qualification property. It shows like this on the page:
I've also tried "Qualification.Id" and "Qualification" as field names to copy, but no dice. At any rate, I'm pretty sure it should be "Id" as in my example though, because the debugger shows the correct GetRowValues return value only for that case.
Second attempt / custom code to handle the dropdown:
So I'm thinking I need to have some custom code to set the NewValue for a dropdown. First I create an EditItemTemplate for the Qualification column like so:
<EditItemTemplate>
<dx:ASPxComboBox
runat="server"
ID="qualificationCombo"
DataSourceID="qualificationsDataSource"
TextField="Title"
ValueField="Id"
ValueType="System.Int64" />
</EditItemTemplate>
And then I add this code to grid_InitNewRow:
// Attempt to set the combo box to a value:
var column = grvPeople.Columns["Qualification"] as GridViewDataColumn;
var comboBox = grvPeople.FindEditRowCellTemplateControl(column, "qualificationCombo") as ASPxComboBox;
var item = comboBox.Items.FindByValue(valuesToClone["Id"]);
item.Selected = true;
And it works! However, now the Name is no longer cloned. It looks like this:
I have no clue why, but the added code has a side-effect causing the NewValues setter approach to fail.
Bottom Line:
The bottom line is rather simple: how do I change the DevExpress example into one that can also clone reference type properties?
PS. I've also cross-posted my question on the DevExpress support forum.

Answer 1

You mention that "Qualification.Id" doesn't work, but you most likely tried that while the EditItemTemplate was there. If there is no such template then that code actually works.
To be complete, change the fieldsToCopy line of code to:
private string[] fieldsToCopy = { "Name", "Qualification.Id" };
And make sure there's no EditItemTemplate, then it'll work.
Alternatively, if you are stuck with a EditItemTemplate for some reason, there's one "solution" to make sure the ComboBox in that template gets bound to the cloned value. Make sure you hook into OnDataBound on the ComboBox with the following code:
protected void qualificationCombo_DataBound(object sender, EventArgs e)
{
var column = grvPeople.Columns["Qualification"] as GridViewDataColumn;
var comboBox = grvPeople.FindEditRowCellTemplateControl(column, "qualificationCombo") as ASPxComboBox;
var item = comboBox.Items.FindByValue(valuesToClone["Id"]);
item.Selected = true;
}
This will properly set the ComboBox to the cloned value, while also leaving the e.NewValues approach for plain fields intact.