Invalid postback or callback argument. Event validation is enabled using in configuration

I wrote web part that uses Repeater control to create some repeating blocks of output. Each of these blocks has Button control in it. When I ran web part under SharePoint I got the following error: Invalid postback or callback argument. Event validation is enabled using in configuration or in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. Here is the solution.

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SPListItemCollection.GetDataTable() – be careful

Seems like I am stuck in ADODB days a little bit and I still expect that query with no results returns at least some meta data. Or at least my code gets no bombed by null references.SPListItemCollection has GetDataTable() method that returns items collection as ADO.NETDataTable objects. Be careful when using this method – if your items collection is empty then this method returns null.

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SharePoint: temporary solution for GetCustomProperty and SetCustomProperty errors

Another day, another kinky problem with SharePoint. This time I struggled with custom properties of my custom field. I tried out different code samples to make GetCustomProperty and SetCustomProperty to work but no luck at all – nothing worked for me. There was no errors when adding field to list or changing field properties but custom properties were never saved.

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Querying SharePoint lists

The best way to get data from SharePoint lists is to query them. Using queries you guarantee that only list items you really need are retrieved from database and constructed to objects by SharePoint. Most of the time you don’t need the full collection of list items, so it is not point to ask all the items and then use only few of these. Let’s see how we can query SharePoint lists.

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