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Asked: 2026-05-30T22:15:56+00:00

I’m trying to implement conflict detection in an admin system i.e. Alice is editing

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I’m trying to implement conflict detection in an admin system i.e. Alice is editing a page; Bob edits the same page and saves before Alice. To prevent Alice overwriting Bob’s changes, I need to make her aware that a change has occurred, and the exact fields she would be overwriting and what Bob had saved them as. (This is all using SQL).

I’ve tried storing the object concerned on Page_Load, but this disappears when the page is posted back. Is there a way of persisting the object without having to write out nasty serialization code? Or indeed a better way of doing it.

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  1. Editorial Team

    If the object isn’t very complicated, just mark it as [Serializable] and shove it into ViewState or SessionState, then it will survive postbacks (Although if you put it into ViewState, you need to put it back into viewstate after a postback, before the page is rendered again).

    Another option, if the object is a bit complicated, or you don’t really want to save that data there is ensure the table in question has fields along the lines of LastUpdated and LastUpdatedBy, and ensure those are written to whenever it is updated. Then what you can do, is when rendering Alice’s page, write out the LastUpdated date into a hidden field (or viewstate).

    Then upon an attempted save, compare the record in the database’s LastUpdated to the one that was attached when the page was rendered. If they are the same, go ahead and perform your update. If they’re different, you have the values Alice wanted to enter, by way of you having them from postback, and you have Bob’s changes, from doing the date check. You can then display whatever UI you want from that.

    EDIT: Some other options if you want to show the original values Alice had when loading the page.

    The first, lowest tech one would be to have a HiddenField corresponding to each editable field. You load those at the same time as you’re populating the controls, and then use that to show the original values.

    Another option, if you’re using ObjectDataSource would be to use it’s ConflictDetection feature:
    http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.objectdatasource.conflictdetection.aspx

    Between this and the OldValuesParameterFormatString property, the control will then pass the original values to the Update function, as well as the updated values.

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