Override SharePoint:SaveButton in custom form template

First let me clear the air and post articles which already explain how to override the SaveButton:

• How to override or customize the Sharepoint SaveButton?
• How to override functionality of the Ribbon Save button
• Override SharePoint Save Button to Provide Custom Functionality

I have read those and understood them, I just don't know how to fully implement it in my particular case:

I have a custom rendering template "CustomRender" which includes the "real form". The code for the real form looks something around these lines:

<%@ Register TagPrefix="wssuc" TagName="ToolBar"
             src="~/_controltemplates/ToolBar.ascx" %>
<%@ Control Language="C#" AutoEventWireup="true"
    CodeBehind=&开发者_运维技巧quot;RealForm.ascx.cs" Inherits="CustomNameSpace.CustomForm" %>
<p>Test</p>
<wssuc:ToolBar runat="server" id="toolbar">
    <TemplateButtons>
        <SharePoint:SaveButton runat="server" />
    </TemplateButtons>
</wssuc:ToolBar>

Now I want to override this save button. The sites above state that I just have to write another control which overrides the button. E.g.:

public class NewSaveButton: SaveButton

{
    protected override bool SaveItem()

    {
        bool success = base.SaveItem();

        RedirectUrl = String.Concat(List.ParentWeb.ServerRelativeUrl, "/",
                      List.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url, @"?ID=", 
                      ListItem.ID, @"&Source=", ListItem.ParentList.DefaultViewUrl);
        return success;

    }
}

Now I just don't know how to register this template inside my other template. Could I not just override the SaveButton in the Code behind of my template - how would I do that and reference it later on?

• Option one: Code-Behind of the form (RealForm.ascx.cs) - can I just put the override method in there? How can I reference the button then in the form (how do I get <NewSaveButton>)?
• Option two: Another template just for the button, e.g. SaveButton.ascx" - how do I reference that via <%@ Register... %>, i.e. how do I know PublicKeyToken etc. when deployed via a Feature. And same thing here: My goal is to get some kind of "<NewSaveButton>" control for the form.

---

You're creating a new server control when you do this, so you'll need to register the new control on the page (or in this case, in the template .ascx file).

<%@ Register TagPrefix="MyPrefix" Namespace="ControlNamespace" Assembly="MyFullyQualifiedAssembly" %>

In your code file you can to add the ToolboxDataAttribute to the class (this is only necessary if you are dragging&dropping the control from the toolbox in visual studio)

[ToolboxData("<{0}:NewSaveButton runat=\"server\"></{0}:NewSaveButton>")]
public class NewSaveButton : SaveButton {}

Now, you should be able to replace the save button on the form with the following:

<MyPrefix:NewSaveButton runat="server"></MyPrefix:NewSaveButton>

You're basically creating a new server control following the rules of asp.net (no sharepoint specific stuff is happening here).

For more information, take a look at this page: http://msdn.microsoft.com/en-us/library/yhzc935f(v=VS.85).aspx

---

On your page with SaveButton you could do the following trick (in my case save button is added in DataFormWebPart's XSL markup):

// On your page with SaveButton you could do the following trick 
// (in my case save button is added in DataFormWebPart's XSL markup):

SPContext itemContext;
DataFormWebPart dataForm; // from designer's code behind

void Page_Init(object sender, EventArgs e)
{
    // NOTE: by some reason ItemContexts of controls in DFWP are differ,
    // so only SaveButton's OnSaveHandler is invoked
    itemContext = dataForm.Controls.FindControlRecursive<SaveButton>().ItemContext;
}

void Page_Load(object sender, EventArgs e)
{
    if (itemContext.FormContext.FormMode == SPControlMode.New ||
        itemContext.FormContext.FormMode == SPControlMode.Edit)
    {
        itemContext.FormContext.OnSaveHandler += OnSaveHandler;
    }
}

void OnSaveHandler(object sender, EventArgs eventArgs)
{
    // TODO: Add your code before saving the item
    SaveButton.SaveItem(saveButton.ItemContext, false, string.Empty);
    // TODO: Add your code after saving the item
}

The FindControlRecursive() extension implementation is

public static class ControlExtensions
{
    public static TControl FindControlRecursive<TControl>
    (
        this ControlCollection controls
    ) where TControl : Control
    {
        if (controls != null)
        {
            foreach (Control control in controls)
            {
                var foundControl = control as TControl 
                    ?? control.Controls.FindControlRecursive();
                if (foundControl != null)
                {
                    return foundControl;
                }
            }
        }
        return null;
    }
}